JP4689555B2 - Ground strengthening method - Google Patents

Description

The present invention is a method in which a plastic gel injection material containing a slag as a main component and containing as an active ingredient a powdery hardening material consisting of one kind selected from the group of cement, fly ash, lime, or gypsum is pressed into the ground. With the passage of time, or by pressing and dehydrating, the soil particles are pushed to the periphery while forming a lump of plastic gel in the ground, and a lump of plastic gel injection material itself is formed in the ground. The present invention relates to a plastic gel injection material to be strengthened, a ground strengthening method, a ground press-fitting management method, and a ground press-fitting management device.

Furthermore, the present invention is to form a bulk body by injection material itself plasticity gel consisting of self-curing powder body plus productive material slag statically pressed into the soft ground in the ground, It is a ground strengthening method that increases the density by compressing the surrounding earth and sand.

  Conventionally, a non-flowable low slump or almost slump-free injection material (mortar) has been used as a method of strengthening the ground by increasing the density by statically injecting the caking material into the ground and pushing the earth and sand around it. ) Is press-fitted into the ground to form a consolidated body in the ground, and a method of consolidation strengthening the ground is known. (Patent Document 1: Japanese Patent Laid-Open No. 6-108449)

  However, the former of the above-mentioned known construction methods requires a large device, and it was impossible to reinforce the construction conditions in which the liquefaction prevention work or the like was built or the foundation directly under the building.

  In addition, mortar mainly composed of flowable cement and plastic material such as water glass and aluminum salt are respectively transferred by a pump and mixed and mixed near the injection port to form a low flow plastic grout having a slump of 5 cm or less. There is also a cavity filling method that forms and injects, but if it is injected under pressure in soft ground, it will lose fluidity rapidly due to dehydration in the ground, and it will be difficult to form a massive gel that expands, or it will be impossible to inject It is difficult to improve the ground because it splits out of the middle range and deviates like a pulse.

  As a result of promoting the research and development of the fluidity of plastic grout in order to expand the bulk gel by press-fitting the plastic grout into the ground, the present applicant has developed a slag-based gel to expand in the ground. A clear condition was found.

  The present inventors achieve the above object by applying a flow characteristic that varies with time after blending a plastic gel injection material containing slag and its cured material as an active ingredient, using a simple method called an injection method. The present inventors completed the present invention by confirming that an expanding massive solid body can be formed under certain conditions.

  When suspension grout or instantaneous grouting is injected into the ground, it is difficult to form a hardened lump in a predetermined region because the ground is split and injected into a vein shape. The inventor of the present invention forms a lump of a plastic gel in the ground by press-fitting a plastic gel injection material formed by adding a curing agent to the slag in the ground or further adding a water retaining material. It is possible to increase the density of the surrounding ground by expanding the mass of plastic gel formed with dehydration in the ground while it has fluidity during the injection process. It is a thing. In this process, these plastic gel injection materials are controlled by the injection method and injection management system that have been upgraded in recent years, so that a predetermined amount of massive gel can be placed in the unit volume of the injection hole without causing splitting in the ground. They found a method to form a hardened body and succeeded in increasing the density of soft ground.

  Conventionally, a mortar injection solution containing cement as a main material has a slurry-like fluidity and solidifies by a hydration reaction. When such a fluid mortar is injected into the ground, it is injected by splitting the ground and easily deviates, and large breathing occurs. The material separates and settles in the ground and solidifies in a pulse shape.

  On the other hand, in order to reduce the breathing, it is sufficient to increase the cement content. However, if this is done, the hardening of the cement will be accelerated and it will not be possible to fill a wide area, or the ground will split and escape. There is. A method of using aluminum or water glass as a plastic material for fluid mortar mainly composed of cement has been proposed, but such plastic grout is suitable for filling the cavity, but this was pressed into the ground. In this case, the viscosity is so high that it hardens rapidly in the ground and cannot be injected, or splits easily.

  Also, cement suspension and plastic material are pumped separately, and a slump formed by joining before the injection pipe is pressed into a ground with a plastic grout of less than 5 cm, compressing the surrounding soil particles. A ground strengthening method has also been proposed.

  However, if the slump is less than 5 cm, it is about 8 cm in the flow by the cylinder, and it is somewhat different depending on the material constituting the grout, but it is about 10 cm in the table flow. In this case, the gelled product hardly moves even when vibration due to dropping is applied. When such a low slump plastic grout is poured into the ground, moisture and powder are separated in the ground, and the fluidity is further lost due to dehydration, resulting in rapid hardening and the plastic holding time cannot be obtained. As a result, the injection pressure increases and the injection becomes impossible or the ground is split like a vein and escapes in an unspecified direction, so that the ground reinforcement effect cannot be obtained.

  Therefore, as a result of various studies, the present inventor noticed that the fluidity of plastic grout changes not only with time but also with dehydration. Even after being pressed into the ground, it loses its fluidity over time or by pressure dehydration to form a plastic gel, which pushes the soil particles to the periphery while maintaining a long flow holding time while it becomes a lump. This is a ground strengthening method that makes it possible to form a large lump in the ground and to strengthen the ground.

JP-A-6-108449 JP 2002-294686A

  For the above-mentioned purpose, the ground injecting material for ground reinforcement and the ground strengthening method require liquid flowability in a hose as long as several tens of meters. On the other hand, when pressed into the ground, it does not penetrate between soil particles, and Even in the ground, while maintaining fluidity, a lump is formed at a predetermined position without deviating due to splitting outside the specified improved coverage, and it grows into a lump as large as possible by the injection solution itself, and solidifies. It is required to simultaneously satisfy the conflicting characteristics of pushing the surrounding soil particles and increasing the density of the surrounding soil by that amount.

  Therefore, the present invention uses slag, which is an industrial by-product, as an active ingredient, and is blended so that a predetermined flow characteristic can be obtained, and a small amount of cement, lime, gypsum, fly ash, and the like and water at a predetermined ratio. Addition of bentonite, clay, silt, polymer agent, water absorption to reduce the dehydration by mixing, improving water retention or improving fluidity and expanding the mass before solidifying in the ground Adds Senyi, white carbon, etc., or adds gelation accelerator, gelation retarder, thickener, peptizer, foaming agent and press fits into the ground under the specified conditions. We have succeeded in strengthening the ground by clarifying the fluidity and consolidation characteristics that make it possible to build a mass or solidified body with a plastic gel, and solve the above-mentioned problems in the known technology Ground injection material and ground strengthening method, And to provide a infusion management method each time. Of course, this ground injecting material can be used not only for the press-fitting method but also for filling the gap such as general backfilling injection, anti-sucking injection for revetment.

The present invention pays attention to the fact that the construction technique that satisfies the following requirements is different from the mere filling of the plastic gel gap for ground strengthening, and these problems are considered as the injection material, the injection method, and its It has been solved by developing a management method.
1) Conditions for an injection material that is formed in a lump shape in a predetermined receiving area and that the lump body expands while maintaining a lump shape without the injection material penetrating between soil particles and without departing from the injection range.
2) A method of compressing the surrounding earth and sand by expanding in the lateral direction.
3) A method of improving the soil density by a simple method of pouring under ground conditions that are high enough to be press-fit with the plastic gel itself but too low for the ground.
4) A technique for minimizing the transfer of the consolidated body in the vertical direction.
5) A technique that can reliably increase the strength by minimizing ground departure and ground uplift in areas close to the ground surface.
6) A technique that makes use of the construction method of the injection method and enables long-distance liquid delivery.
7) Development of an injection management system that enables the above.

  The inventor found that the fluidity until the injection solution was injected into the ground, the fluidity in the ground, the formation of a massive solid body and the growth to a large diameter without infiltration or split injection between soil particles. In order to solve this problem, attention was paid to the fact that a mixture of slag, its hardener and water is reduced in fluidity in the process of dehydration in the ground, and forms a lump in the ground. And as an index showing the above flow characteristics of the injected liquid in the ground, (1) flow and slump value showing fluidity, (2) gelation time by plastic gel, (3) plastic retention time, (4) We focused on the solidification time to become non-plastic.

Of these, the gelation time is the time when the table flow is 20 cm after blending, and the plasticity retention time is the time when the gel does not flow even when external force is applied after gelation, that is, the penetration resistance value exceeds 0.01 MN / m ² . It was set as the time until the time point.

  We paid attention to the fact that these are greatly influenced by the change of water powder ratio due to the phenomenon of press-fitting dehydration in the ground. Furthermore, since the strength is low if the amount of the hardening developing material is small, it is found that a massive solid body is formed by the injection material itself by expanding greatly into a lump shape without being split injected while maintaining fluidity in the soil. It was. In this case, since the strength of the cured product is relatively low, high-strength piles such as cement consolidated bodies are not formed in the ground after construction. We focused on being able to keep it integrated.

  As a result of various studies to solve the above problems, the present inventor has found the following.

1) Slag, which is a silica-based powder, reacts with a small amount of Ca composition such as cement and lime, and adsorbs Ca to the surface at an early stage to cause an electrochemical reaction to become a binder. When the water powder ratio decreases with further dehydration and further dehydration occurs, a plastic gel is formed and further solidified via a non-plastic gel. Such a phenomenon can achieve the effect of the present invention as long as the lump formed by dehydration in the ground is stronger than the surrounding ground. Even without adding a hardened material, its flow characteristics are specified by flow or slump, or water content is specified by the water-powder ratio, so that it can penetrate between soil particles in the ground, or it can be pulsated. Without diffusing, the lumps are enlarged by forming lumps in the ground and continuing the press-fitting. The present invention has found that as long as the dehydrated mass in the ground maintains the same strength as the surrounding compressed ground or higher strength, it serves to strengthen the ground.

2) The flow through the table flow, slump, and cylinder shows the fluidity of the injection solution in which the hardened material is added to the slag, the table flow is in the range of 15 cm to 28 cm, the slump is in the range of 10 cm to 28 cm, and the flow through the cylinder is about 10 It is in the range of ~ 26cm, the table flow is around 20cm, the slump is around 21cm, the flow through the cylinder is around 15cm, and it becomes a plastic gel, and the flow and slump decrease with time or the water powder ratio decreases due to dehydration. . By adjusting the ratio of the powder body consisting of a powder-type hardened material containing slag and Ca, which is a silica-based powder material, and the ratio of the hardened material material in the entire powder, the plasticity of the above ground-injected material in the ground Adjusting the flow characteristics and expansion of the plastic gelled material in the ground, and further the gelation time and plastic holding time until reaching the plastic gel, an accelerator or a retarder, a fluidizing agent, The workability and the size of the plastic gel can be adjusted by using additives such as a water retaining material, a peptizer, and a foam material. If the water powder ratio is too small, or if the ratio of the cured material is too large, the expansion of the massive gel in the ground is inhibited by dehydration, so that ratio is important.

  In particular, if the ratio of hardened material is large, it will rapidly become too strong due to dehydration in the ground, not only preventing the gel from expanding, but also as if a large concrete body was created with respect to the surrounding soil, so that the entire ground could be integrated. The earthquake resistance of the improved ground deteriorates because it is prevented and breaks by generating a large local stress during an earthquake. In addition, the fluid injection solution made of silica-based powder that forms a lump by dehydration in the ground is made of not only the above-mentioned artificial powder material but also excavated earth and sand, etc., and clay and thickeners. Or water retention material is added to make the fluidized soil have a predetermined flow characteristic, that is, a flow or slump value, and is adjusted so as to exhibit a predetermined water powder ratio, and when dehydrated and the table flow becomes 20 cm or less, it is plastic. It is possible to improve the predetermined ground by making the surrounding ground denser by injecting it so that it does not penetrate between the soil particles and does not escape from the crack. Needless to say, the strength increases if a curing material is further added as the material.

3) The fluidity of the ground injection material fluctuates with time during the liquid feeding process and the press-fitting process into the ground. While it is possible to form a massive solid body in the ground by effectively utilizing the change in the flow characteristics, this makes it difficult to adjust the composition and control the injection, so not only the setting of the mixing range, The press-in management system becomes important.

4) Workability suitable for kneading and pumping of the ground injection material and press-fitting into the ground is 12 cm or more, preferably 15 cm or more and less than 30 cm, more than 5 cm slump, preferably 10 cm or more and 28 cm or less. The flow by the cylinder is larger than 8 cm, preferably not less than about 10 cm and not more than 26 cm. The determination of the water / powder ratio that governs slump and flow has a major impact on workability and the formation and expansion of lumps in the soil. It is possible to accurately determine the fluidity that changes sequentially with time, and to control the water powder ratio and the hardening material ratio by slump and flow to quickly adjust the composition and the liquid body ratio. Important for forming and expanding gels.

5) When an additive is added, the gel time for forming a plastic gel according to the amount added can be adjusted. By adding water glass or aluminum salt as a promoter, the flow can be easily reduced or the gelation time can be shortened. Also, the slump can be reduced from around 20 cm to 10 cm or less. In addition, a plastic gel is formed with dehydration in the ground, and by continuing the press-fitting for a longer time for the gel to retain its plastic shape, the bulk gel grows to form a large bulk gelled product in the ground, which is further unplasticized. It can be changed into a cured product through gel.

  In this case, a mixture of the silica-based powder and its curing agent is used as liquid A, and solution silica such as water glass or aluminum salt is combined as liquid B, so that a small flow or low slump plastic grout can be obtained. Can be injected. However, it is possible to inject plastic grout with a low flow value and low slump in the case of cavity filling, but in the case of press-fitting to the ground, fluidity is lost rapidly due to dehydration that occurs in the ground, so that the bulk gel It becomes difficult to compress the surrounding ground due to expansion. For this reason, it is necessary that the table flow of the merged liquid is 12 cm or more, the slump is larger than 5 cm, and the flow through the cylinder is larger than 8 cm at the time when it is injected into the ground from the injection tube discharge port even if the combined injection is performed.

6) On-site generated soil such as clay and earth and sand can be added as aggregate. Aggregate not only serves as an extender, but also helps to adjust consolidation strength and fluidity. Generally, the strength decreases as the ratio of aggregate in the powder increases, and the fluidity decreases as the particle size of the aggregate increases.
Clay such as bentonite, clay, silt, loam, etc., fine particles, polymer agents, thickeners, etc. are excellent as water retention and thickeners, delaying the dehydration of the press-fitted material in the ground. It acts as a binder with a pseudo-bonding property by acting as a binder for the particles, and forms a lump gel without separation and dispersion, and helps to enlarge it.

7) Slump reduction, flow when aluminum salt such as aluminum sulfate or water glass (including acidic water glass obtained by mixing water glass and acid is also regarded as water glass in the present invention) is added. Decrease in viscosity and increase in viscosity. In order to grow a massive gel by forming a plastic gel in the ground without causing the ground injection material to split into veins in the ground, the hardened material expression ratio, water body ratio, aluminum ratio, flow value, slump value The selection application method of the range, the silica concentration from the silica solution, etc. is important.

8) Cement-based suspension grout is very viscous, but if it is made plastic, the resistance of press-fitting from the injection port of the injection tube that opens into the ground and the liquid feed tube up to the injection port There is a problem that the liquid feeding resistance is extremely large and the liquid feeding pipe and the pump are easily clogged. For this reason, if a thin composition is used to facilitate liquid feeding, it becomes a vein in the ground. For this reason, in the technology of the prior application, like the backfill injection, a cement-based suspension with good fluidity and a plastic material are mixed at the time before being sent to the injection pipe, and instantly plasticized into the ground. A method of press-fitting with a slump of less than 5 cm has been proposed. However, the cementitious plastic grout plasticized in front of the injection tube immediately becomes high strength due to dehydration in the ground, so it is difficult to grow into a large lump gel, and it is impossible to inject due to the high injection pressure. Or destroy the ground and deviate.

  The present inventor has noted that the injection of ground improvement that compresses the surrounding earth and sand by press-fitting into the ground to form a large gel, compared to injection of plastic grout for backfill injection and void filling, has been noted. .

As a result of research, the present inventor has found the following necessary conditions for the press-fit material not to deviate by splitting in the ground and grow into a large lump gel, and the mechanism of formation and expansion of the lump gel.
1. The ground injection material is fluid until it is injected into the ground, but after it is injected into the ground, it should not deviate by splitting the ground.
2. The ground injection material reaches the plastic gel before being injected into the ground, or is injected into the ground and reduced in fluidity by pressure dehydration to form a lump of plastic gel. Thing.
3. The lump retains its plastic shape in the ground, and the lump is expanded by a plastic gel that is subsequently pressed into the lump, thereby expanding the lump. Results that are pushed open in the outer peripheral portion of the masses, further dehydrated to become a non-plastic-like loses fluidity, with large masses consolidating bodies form a solidified body from the outer peripheral portion with time is formed, the peripheral portion It reduces the voids in the earth and sand, spreads them, and pre-sets them statically.
4). Since the inside of the lump has a plastic shape, if there is further injection of the ground injection material, some solidification zones on the outer periphery of the lump will be broken, and the plastic gel will be pushed to the periphery to dehydrate it. As a result, it becomes non-plastic and the solidified body expands. When the solidified body becomes harder than a certain level, it becomes difficult to break through with normal pump pressure, and press fitting becomes impossible. The time becomes the size of the lump solidified product.

  As a result of research, the inventor has found that fluidity is maintained even after being injected into the ground from the tip of the injection pipe installed in the ground without causing resistance pressure in the liquid feeding pipe during pumping or clogging in the pump. And forming a plastic gel having a plastic holding time in the ground (a time when it is pressurized to be in a fluid state) by press-fitting the ground injection material that exhibits a plastic shape even when dehydrated, Furthermore, the present inventors have found that a massive body grows and completed the present invention.

  For example, as shown in Table 2, Formulation Example 1 having the same cured material ratio of 8.05% and a water powder ratio of 70% and Formulation Example 2 having a water powder ratio of 60% become a plastic gel after blending. Gelation time up to 210 minutes or 90 minutes respectively. When the water powder ratio becomes 50%, the gelation time becomes 1 minute. This means that at the time of blending, when the injected material that has not reached the plastic state before being injected into the ground is mixed, the water body ratio is 70% → 60% (dehydration rate about 15%) → 50 due to dehydration. % (Dehydration rate of about 30%), the gel time is reduced to 1 minute, forming a plastic gel and forming a lump.

  In addition, since the plastic holding time is 6 hours at the time of gelation, the bulk gel expands, the breathing is small, the viscosity increases, it is difficult to diffuse, and the solidified product has high strength. Such characteristics have not been known so far. That is, the flowable injection material does not reach gelation until the water powder ratio is dehydrated from 70% to 60% after being pressed into the ground, and becomes 50% (dehydration rate is about 30%). After a minute, a plastic gel is formed, and the plastic retention time at that time is 6 hours. As the press-fitting continues, the gel remains large and non-flowable as the dehydration or curing phenomenon progresses. It tells that it becomes a gel and solidifies.

  Therefore, even if it does not exhibit plasticity at the time of injection, it can become plastic by dehydration in the ground. In the injection of such fluid injection solution, even if the compounding solution is injected as a single solution, the powder injection solution is set as A solution, and the gelation promoting material such as aluminum and water glass is set as B solution. Alternatively, the liquid A can be applied to any plastic gel and the liquid B can be used as a gelation accelerator such as water glass regardless of the means.

  As a result of the above research by the present inventor, a reliable ground improvement method that can be designed by increasing the strength by press-fitting a plastic gel injection material to form a large lump in the ground as follows is possible. became.

1. The infusion solution itself is fluid by the pump, but the one injected into the ground will split into veins so that it will not penetrate and solidify indefinitely. This is because only when a solid aggregate is formed by gelation within the range of each injection hole, the soil particle gap in that range decreases and the density of the ground between the injection holes around the mass is increased. This is because it can be expected with certainty.

2. The material injected into the ground is prevented from penetrating between the soil particles, and the soil particles on the ground between the plurality of injection holes are pushed away by a lump. This is because if the injection solution penetrates between the soil particles, the ground between the plurality of injection holes cannot be compressed, and an increase in density due to the compression of the ground in the range of the injection holes cannot be expected with certainty. .

3. The gel press-fitted into the ground forms a consolidated body in a lump shape and grows into a large-diameter consolidated lump. To this end
(a) A mixture of silica-based powder and water as the injection material is larger than 5 cm slump and / or a table flow of 12 cm or more and / or a cylinder flow is larger than 8 cm, or further within a slump of 28 cm and / or a table flow. Is less than 30 cm and / or a fluid ground injection material with a cylinder flow of less than 28 cm, or a ground injection material mixed with a powdery hardening material containing Ca, and this is pressed into the ground. The soil particles are pushed to the periphery by enlarging the lump made of the injection material itself that is formed by dehydration to create a lump consolidated body in the ground to strengthen the ground.
(b) The ground injection material can reach a table flow of 20 cm or less by dehydration. Here, the time when the table flow becomes 20 cm is regarded as the time when the plastic gel is formed.
(c) As the dehydration proceeds, the ground injection material passes through a plastic gel and becomes non-plastic and solidifies.
(d) The ground injecting material is a curable fluidized soil or a non-hardened fluidized soil, and loses fluidity by dehydration, and the table flow reaches 20 cm or less and exhibits a strength equal to or higher than that of the surrounding ground. To do.
(e) If the ground injection material has a water powder ratio of 30% or less and becomes a plastic gel, if it continues to be pressed into the ground, it becomes a plastic gel and a massive solid body is formed.

  The conditions shown in Table 1 are preferred in order that the lump formed by the plastic gel grows greatly in the ground to become a consolidated body.

4). Near the ground surface, the ground tends to rise, and the injected solution tends to deviate to the ground surface.

5. The ability to maintain fluidity without separation in a long-distance liquid feeding pipe enables workability for applying this technology to seismic reinforcement of ground with dense buildings.

6). Make it applicable not only to sandy ground but also to viscous ground.
In the route that is injected into the ground from the blending system of the injected solution through the liquid feeding tube and the injection tube line, while maintaining fluidity (the above requirement 5), the above 1, 2, 3, 4 or 4 is satisfied.

  In order to shorten the time until the plastic gel is exhibited, it can be adjusted by adding water glass or aluminum salt. That is, they act as gelation accelerators. When acidic water glass obtained by mixing water glass and acid such as sulfuric acid to remove alkali of water glass is used, a gel is formed very quickly. In the present invention, acidic water glass is also treated as water glass. In this case, the gelation time can be adjusted by using sodium bicarbonate or sodium carbonate in combination. A gel retarder such as lignin sulfonate can also be used.

A typical example of the ground injection material of the present invention is a powder made of cement, slaked lime, gypsum, fly ash or the like to be added to the slag, which is a powdery silica-based powder that is the main material constituting the suspension. a kind of productive material Jo is less than 50 wt% in powdery material used, preferably 1 to 40 wt%, more preferably 1-20 wt%, and water particles versus 20 to 200 wt%, preferably Is 30 to 150% by weight. When adding a gelation accelerator, the aluminum ratio is 0.1 to 3.0% by weight (in terms of Al ₂ O ₃₎ with respect to the total amount of the powder contained in the injection material, that is, the main material and the curing material. 0.01 to 0.52%) By mixing, the table flow is 12 cm or more and less than 30 cm, preferably 15 to 28 cm, the gel time is within 3 minutes to several hundred minutes, the plastic holding time is several hours to 10 hours or more, and breathing The rate is within 10%, preferably within 5%, the slump is greater than 5 cm and less than or equal to 28 cm, preferably 10 to 28 cm, and the flow through the cylinder is greater than 8 cm and less than 28 cm, preferably about 10 to 26 cm.

  Due to these characteristics of the present invention, addition of silica such as water glass or acidic water glass as a gelation accelerator can greatly reduce gel time and plastic holding time, and also breathing and slumping. Furthermore, the flow becomes smaller. The ground injecting material of the present invention is pressed into the ground to become a plastic gel and pushes the soil particles to the periphery, grows into a large aggregate in the ground, and can strengthen the ground.

  As described above, the present invention uses a silica-based powder or a suspension to which less calcium-based curing agent is added, but is blended at a specific blending ratio and the type and combination of powder materials used. Therefore, the soil of the ground surrounded by the injection hole is formed by press-fitting a desired injection material exhibiting flow characteristics and consolidation characteristics according to the purpose into the ground, and creating a massive solid body in the ground. It is possible to push the particles around and strengthen the ground.

  It is a ground injection material that forms a plastic gel that can flow by pressurization, but does not penetrate between soil particles and does not split into veins. It is a ground press-fitting material showing a range of 12 cm or more and less than 30 cm, preferably 15 to 28 cm, more than 5 cm for slumps, preferably 10 to 28 cm, more than 8 cm for cylinder flow, preferably about 9 to 26 cm. Is preferred. Also, considering the formation of a plastic gel by pressure dehydration in the ground, it is a plastic gel before injection or a water-to-powder ratio is reduced within 30% and a plastic gel It is preferable to be within 20 cm).

  If the flow value or slump is below this level, it will be difficult to grow a solid aggregate of plastic gel in the ground, and if it exceeds this value, it will be split and injected into veins or cracks before it can be dehydrated, forming a mass. Hateful.

As described above, the present invention blends the powder material of the hardening developing material added to the slag that is a silica-based powder and water in a specific ratio, but as a hardening developing material containing calcium, cement, lime, gypsum, fly ash, Any of ( C material) and water (W material) are mixed.

In the above, the slag may be a general product such as a normal 4000 (cm ² / g) brane, or may be an ultrafine particle slag such as 6000 to 15000 (cm ² / g) brane.

  The ratio of the cured material is less than 50% by weight, preferably 1 to 40% by weight, more preferably 1 to 20% by weight, and even 1 to 10% by weight has a very excellent effect. When the hardening expression material is 0, it is necessary that the slump and the flow satisfy the above conditions, and the lump that is dehydrated and press-fitted into the ground has the same or higher strength than the surrounding ground.

  In this case, the composition and the water / powder ratio can be selected by filling the casting material in a mold with porous stones or filter paper on the top and bottom, pressurizing it with a cylinder at a pressure corresponding to the assumed filling pressure, and dehydrating it. Further, the strength of the test specimen can be measured and set so as to be equal to or greater than the strength corresponding to the average soil density of the surrounding soil after the injection. Of course, the composition can be similarly set when a small amount of the curing material is added. The water powder ratio is 20 to 200%, preferably 30 to 150%. Here, the cured material ratio is C / (S + C) × 100, the water powder ratio is W / (S + C) × 100, and S, C, and W are weights, respectively.

  When such a liquid mixture is mixed, it remains as it is when the water powder ratio is small, and when the water powder ratio is large, it is dehydrated in the ground and sooner or later becomes a lump. The plastic gel flows when force is applied, but stops flowing when it stops. The gel time for forming a plastic gel is when the table flow is approximately 20 cm. Even when the water powder ratio is large, the plastic gel is formed in the ground by leaving the fluid infusion material exhibiting the above water powder ratio, flow, and slump as it is or by adding the additive and dehydrating under pressure in the ground. I can do it.

  The lump formed in the ground needs to be enlarged as wide as possible to form a large lump solid body while being in a state of low fluidity. For this purpose, the flow, slump and water / powder ratio are important, and the ratio of the curing material and the additive are also important.

  If the ratio of cured material is excessive, the characteristics of the mortar grout made mainly of cement, etc. will be strong, the water will separate, the breathing will increase, and it will be difficult to become a plastic gel. It becomes a gel and solidifies in a short time to form a high strength consolidated body. For this reason, it splits and deviates or solidifies and becomes impossible to inject. Mass solidification that has a cured material ratio of less than 50%, preferably 1 to 40%, more preferably 1 to 20%, most preferably 1 to 15%, and has grown greatly through a plastic gel in the ground Things are formed. In particular, when the ratio of cured material is 1 to 20% or even 1 to 10%, the strength is low, the plastic gel retention time in the ground is long, and it is easy to expand, and the improved ground has an equal strength. It is integrated with the surrounding ground where the density is increased and has excellent earthquake resistance.

Furthermore, the present invention provides slag, any one of cement, lime, gypsum, fly ash as a hardening developing material, and a hard suspension composed of water, such as aluminum sulfate and polyaluminum chloride in order to adjust the time for developing plasticity. The aluminum salt can also be included. In this case, it is preferable that the ratio of the cured material is 2 wt% or more and less than 50 wt%, the water powder ratio is 20 to 60 wt%, and the aluminum ratio is 2.0 wt% or less, preferably 0.1 to 1.0 wt%. The blended grout is 0.01 to 0.35% by weight in terms of Al2O3. Here, the aluminum ratio is aluminum material / (S + C) × 100. Aluminum material represents weight.

  In the above, the aluminum salt or water glass as a gelation accelerator may be mixed with a silica-based powder or a hardening developing material and press-fitted into the ground with a pump, or in the injection tube or in the injection tube. It may be merged and mixed in the vicinity, or a gelation accelerator may be further merged and injected in the course of injecting a mixed solution of a silica-based powder, a curing agent and a gelation accelerator.

Furthermore, in the present invention, gypsum, or any of gypsum and cement, lime, fly ash ( G) and water (W) are mixed as a hardening developing material. A blended grout having a gypsum ratio or a mixture ratio of gypsum of less than 50% by weight, preferably 2 to 40% by weight, and a water powder ratio of 20 to 200% by weight, preferably 30 to 150% by weight. Here, the gypsum ratio and the mixture ratio of gypsum are G / (S + G) × 100 (%) , and the water powder ratio is W / (S + G) × 100 (%) . G , S, and W all represent weight.

Furthermore, the present invention adds in-situ generated soil such as incinerated ash, clay, earth and sand, silica sand, etc. to slag as the main material of the granular material, and cement, lime, gypsum, fly ash as the hardening developing material and Add to water and mix. Further, the ground injection material of the present invention can be improved in fluidity by adding a foaming agent or a foaming agent, or reduced in weight. In the above, by adding bentonite and further polymer thickeners such as polyvinyl alcohol, carboxymethylcellulose (CMC), methylcellulose, etc. as clay, water dispersibility is suppressed, precipitation is reduced, and workability is improved. It acts as an effect or as a water-retaining material and as a binder of the above-mentioned powder material that is the main material, and forms a fluid having a structure that is difficult to disperse while maintaining fluidity in a pseudo-gel form. As a result, the dehydration in the ground is reduced and the expansion of the blockiness is promoted.

  The present invention should be called a static plastic gel press-in method, and does not generate vibration or the like in a large machine like a sand compaction method, and a non-fluid mortar like a low slump mortar press-in method. Large equipment is not required unlike the press-fitting method. For this reason, the construction method of the present invention can be said to be a construction method having excellent workability with no pollution because it can be easily constructed statically and without noise and in a narrow work area using a simple apparatus used in a normal injection construction method. In addition, since it can be injected through an injection pipe that can be installed by boring in a curved shape, it can be injected obliquely under the building, horizontal injection, as well as seismic reinforcement injection directly under the building combining curved and horizontal. The construction method of the present invention will be described below.

  The above-mentioned ground injection material according to the present invention is suitable for filling the gap of the old tunnel, filling the back of the shield tunnel, filling the gap of the foundation, filling the gap of the revetment back through the injection pipe inserted into the ground. However, it is suitable for the restoration injection method of a building that has been submerged by the same principle, such as pressing into the ground, pushing soil particles to the periphery and solidifying it in a lump, pushing the surrounding soil and strengthening the ground. In injecting such plastic injection material, the initial injection pressure is lowered and the injection pressure is increased stepwise while dehydrating the preceding injection, or injection is performed while intermittently pressurizing by repeating injection and interruption, Thus, the gelled product exhibiting plasticity may be consolidated while increasing the density of the ground by spreading the soil particles to the periphery while preventing the penetration due to the penetration between the ground particles and the splitting of the ground.

  In addition, this injection is performed by simultaneous injection from a plurality of injection points, switching injection to another injection point, that is, continuous injection as shown in FIG. 2 (b), and shifting from one injection point to another injection point. An interval injection method in which the injection is performed again after returning and then repeatedly injected, or a combination of these methods is performed.

  Furthermore, the ground injection material according to the present invention can be injected from a plurality of injection points to constrain the ground between the injection points, and the ground density between the injection pipes can be increased to consolidate the ground. In order to expect such an effect, it is desirable to install a plurality of injection pipes on the ground at intervals of 0.5 m or more and 3 m or less. If it is more than this, the integrated ground improvement effect of the entire press-fitted ground due to the density rise cannot be obtained, resulting in local ground improvement. In addition, when injecting the injection material of the present invention into the ground, if the ground is a viscous soil or a ground with a viscous soil layer interposed, a drain material is installed in the ground and the plastic injected material injected into the ground. It is more effective if injection is performed while promoting dehydration or ground dehydration.

The above-described injection is performed using, for example, the following injection tubes shown in (a) and (b).
(a) An injection tube having a drilled portion or discharge port at the tip.
(b) An injection tube having a plurality of discharge ports in the axial direction.
(c) An injection tube having at least one bag packer on the outer tube.
(d) An injection pipe provided with a water suction port covered with a discharge port and a water-permeable material in the pipeline.

  If an excessive amount of plastic gel is formed in the ground at the same time in order to greatly improve the strength of soft ground, etc., the ground surface will be raised, the ground will be destroyed in the lateral direction, and the There is a tendency that the strength of the ground does not improve as set. For this reason, it is desirable to take advantage of the characteristics of the ground injecting material and to inject at a low discharge amount at the initial stage of injection, gradually increase the injection pressure, and continue to press fit within a predetermined injection pressure range to increase the injection amount. The improvement strength after injection can be grasped from the strength (N value, etc.) of the ground before injection, the injection depth (top loading pressure), the injection pressure, the injection amount, and the handling area per one. Or more accurate if the ground displacement is taken into account. In addition, fluidity is present during the injection, and when the injection is stopped, the fluidity stops and gelation or pressure dehydration occurs, and a pseudo-solid state appears. Inject at repeated intervals) to make it quasi-solidify, compacting without destroying the injected ground, disperse the excluded water among the surrounding soil particles, It is also effective to perform dehydration, increase the consolidated diameter of the gelled product, or inject these grouts with a certain time lag (time difference).

  For example, in the case of vertical injection, injection is performed by repeating the interval method, and the ground injection material is pressed into the ground injection material previously injected, and the ground is split. By repeatedly press-fitting the ground injection material, the side of the ground is consolidated and dewatered to strengthen the ground. Alternatively, a predetermined number of holes are formed in a predetermined area of the ground, and the ground injection material is not injected into the ground injection material at a single point through the predetermined time lag for each hole. In this way, the design injection amount can be divided into several parts. In this way, the plastic grout of each drilling hole is injected with each soil layer at each predetermined time lag by an interval method for each stage, and the plastic grout previously injected consolidates the surrounding ground, or by itself, Alternatively, when the injection solution is dehydrated, the ground injection material to be injected into the predetermined number of holes is added to the ground of each hole by each soil layer or each stage. Similarly, it is possible to perform consolidation dehydration on the side, increase the strength, suppress the displacement as a whole, and enhance the strength of the ground in the predetermined area.

  For example, an injection tube with a discharge port at the tip is inserted up to a predetermined depth, and the step of pulling up the injection tube is stepped up so that the discharge port is positioned within the range of the plastic gel before becoming a non-plastic gel. Enlarge and press the gel lump. Furthermore, the bag body is set in an area near the ground surface in the injection tube to be inserted into the drilling hole, the suspension type grout is press-fitted inside, the bag is inflated to the periphery, and the surrounding ground is consolidated. By improving the ground surface without deviating from the plastic injection material and press-fitting the ground injection material from below the bag body, the plastic gel does not get over the bag body cured body. Due to the restraining effect, there is no displacement of the ground uplift and the like, and the strength due to the ground dewatering action can be achieved over the entire area, and the strength can be improved over the entire region.

  In this case, it is preferable that the installation area of the bag body be within a depth close to the ground surface, for example, within a 3 m range (particularly, a 1.5 m range). This is because even in a plastic gel, this region tends to deviate to the ground surface. For the same reason, it is possible to equalize the compression of the ground surface and prevent the ground surface from being raised by installing injection holes densely in a region close to the ground surface. This is because in a region close to the ground surface, for example, within 3 m (especially within 1.5 m), if a large amount of injection is carried out from a single injection hole, the soil cover will be small and it will be easy to deviate from the ground surface and cause ground uplift. It is easy. Therefore, in this region, the vicinity of the ground surface can be uniformly strengthened by making the injection hole denser than the region having a large depth and reducing the injection amount per one.

  In addition, the ground improvement on the ground surface is likely to cause a ground uplift due to a low overlay pressure, and the ground uplift reaches a diameter of several m on the ground surface. Therefore, the injection hole to be injected is not transferred to the adjacent injection hole, but is transferred to the injection hole outside the influence range of the ground uplift, and the injection of the adjacent injection hole is performed when the ground uplift is cured. desirable. In the area close to the ground surface, the injection step is shifted from the upper part to the lower part, the ground injection material is press-fitted to compress the ground near the ground surface, and then the injection pipe is inserted to the bottom of the improved ground. By shifting the injection step upward from the base, the ground surface ridges can be reduced by the injection, or the lower restraint can be reliably improved by the upper restraint effect.

  In addition, in order to eliminate soil moisture in the injection of this ground injection material into the ground, drainage material for drainage is also provided, and intermittent drainage effect (injection is suspended) It is possible to promote the side consolidation dehydration effect of the ground by dehydrating during the operation, or to accelerate the dehydration of the plastic injection material (application of this drain material is suitable for the strengthening of the soil of the cohesive soil layer) ). Alternatively, drainage pipes are installed to remove groundwater and increase the speed of consolidation. By providing a water inlet in addition to the outlet on the side surface of the injection pipe, the drain effect can be achieved by sucking in excess water or soil water from the inlet through the inlet while injecting the inlet from the outlet.

  Furthermore, in order to measure changes in the ground uplift, etc., a sensor such as a laser measures the change in real time and grasps the amount of compression of the ground, or responds immediately when the change causes an abnormal design. The injection of plastic grout is adjusted, or the injection volume and injection depth are changed via the controller of the injection device, or the specific gravity of the injection solution, injection volume, interval time, etc. are automatically switched. It is possible to move to another stage before the predetermined displacement is exceeded, and the ground strength can be reliably improved by compaction dehydration as designed. In addition to measurement, a measuring rod with a strain gauge can be set in the ground to detect changes in the ground part in the direction of measurement, and a pore water pressure gauge is installed in the ground to determine the consolidation dehydration status. Can

  FIG. 1 shows the injection arrangement. In this invention, when the ground injection material is pressed into the soft ground from the injection pipe at a low speed, the plastic gel exhibiting fluidity expands the range of the bulk gel while the injection pressure is applied. In the advanced part, the water content of the grout is reduced by dehydration to the surrounding soil particles by the injection pressure, the fluidity is lost, and the plastic gel is changed to the non-plastic gel. In this way, the density of the soil between the injection holes is increased, the strength of the ground is increased, and the ground is strengthened. The injection hole interval is effectively 0.5 to 3.0 m depending on the quality, the target improvement degree, and the size of the soil cover.

  Next, an embodiment of the invention of this application will be described as an embodiment example with reference to FIG. In this case, as shown in FIG. 2A, the rod injection tube is used to sequentially inject from the bottom to the top or from the top to the bottom. Alternatively, a double pipe double packer injection outer pipe may be installed to inject from the inner pipe through a plurality of discharge ports. In this case, it is preferable from the viewpoint of enlarging the gelled product that the stage is moved so that the discharge port is located in a range in which the plastic gel in the ground is in a state before becoming the non-plastic gel.

  The embodiment of FIG. 2 (b) shows an aspect of the basic example of the interval system, and the drilling holes 4 are formed in a predetermined soft ground 3, and in the same manner as in the conventional mode, in a lateral direction with a predetermined pitch. Is formed at a predetermined depth, an injection pipe 9 (not shown) is inserted into the drilling hole 4, and a suspension type plastic grout is injected from an injection apparatus (not shown) on the ground by a predetermined time lag at a predetermined stage of the injection pipe 9 Further, the injection is repeated through a predetermined step-up or step-down, and the injection is repeated for each zone of the ground 3 in a chasing manner. In this case, an injection tube rod may be used as the injection tube, or injection may be performed by inserting the injection inner tube into the outer injection tube and moving the injection stage.

  In this case, the injection in each cycle is injected at a low pressure so that it does not deviate in the initial stage of injection, and it is injected while draining the ground 3 or dehydrating the injection solution, and after a predetermined timing, When the pumping is stopped, the fluidity is lost and solidified with time as described above, and the ground injecting material to be injected later pushes the plastic gel formed in advance from the inside to the side, and the upper ground direction. Injected in a laterally polymerized manner without deviating from the side, compacted dehydration of the side ground, dehydrated in the external part of the injection site, cured by a hardened plastic gel Is formed, and the plastic gelled material by the ground injection material for post-injection overlaps to increase into a large lump.

  In this case, a predetermined number of holes 4 are formed in a predetermined area of the ground 3 at predetermined intervals in the transverse direction, and injection pipes 9 are inserted into the respective holes separately. The time 5 lag is connected to the injection device via the valve 5 and the pump p, and the injection material to the drilling hole 4 is shifted via the computer by a controller 6 having a computer to shift the injection timing of the ground injection material through the computer. For the holes 4 formed in parallel in the lateral direction, the ground injection material is injected by the interval method at a predetermined time lag through the valve 5 and the controller 6 and the adjacent holes 4 side of the ground. Consolidation dehydration of the entire area can be performed, and as a result, the strength of the entire area can be improved.

  In other words, the improved ground is injected through the injection hole, and if a large amount of the ground injection material is injected into a predetermined region at once, the surrounding soil may be destroyed before the sufficient area is consolidated, or the ground may rise. However, if the total injection volume is divided and press-fitted at intervals, it will be plastic, so the flow will stop due to the interruption of the injection, it will be held in that position, the surrounding soil will be consolidated and dehydrated, and the plastic grout Given the time for dehydration, the size of the solidified body by the bulk plastic gel grows sequentially, and the composite ground with an increased density sandwiched between the columnar solidified body and the columnar solidified body.

  Of course, in this mode, by taking a predetermined interval method, it is possible to return to the initial drilling hole 4 after making a round of all the drilling holes 4 at a predetermined timing. In the injection of the board injection material, the formed mass of the plastic gel is solidified and maintains a compacted state with respect to the ground 3. In other words, the improved ground is injected through the injection hole, and if a large amount of the main ground injection material is pressed into a predetermined area at once, the surrounding soil will be destroyed before the sufficient range is consolidated. When it is divided and press-fitted at intervals, it is plastic, so the flow stops when the injection is stopped, and it is held at that position, and the surrounding soil is given a time for consolidation dehydration and a time for dehydration of the plastic gel. The size of the consolidated body by the plastic gel grows and becomes a composite ground of the columnar consolidated body and the increased density region sandwiched between the columnar consolidated body.

  For this reason, the injection pressure produces a consolidation action in the lateral direction rather than acting on the ground uplift.

  In addition, due to the function of the plastic gel injected at a predetermined time lag in the axial direction upward of the drilling hole 4, the displacement is more likely to occur in the horizontal direction than in the vertical direction, and therefore, the upward protrusion of the ground 3 can be avoided.

  Fig. 2 (c) shows the strengthening of the ground when an injection tube 9 having an injection tube having tensile strength (or a reinforcing material obtained by tying the injection tube with a tensile material) is placed on the ground and a plastic grout is press-fitted. The model is illustrated. As shown in Fig. 2 (c), the ground is compressed by forming a solid body in the surrounding ground by drilling the ground and embedding the injection pipe 9 and press-fitting the plastic injection material at a predetermined position. Thus, a large soil anchor is formed by consolidation. The injection pipe 9 having a tensile strength is fixed to the ground by the soil anchor. Even in this state alone, if the ground is displaced, the tensile body is stretched and tensile strength is imparted to the ground.

  2 (a) and 2 (b), when injecting from the outer injection tube through the inner injection tube, the outer injection tube having a plurality of discharge ports in the axial direction is covered with a rubber sleeve over the discharge port. To play a role. An injection inner tube having a single packer or a double packer is inserted into the injection outer tube, and the ground injection material is press-fitted from the lower outer tube discharge port, and then stepped up and pressed to strengthen the ground.

  In this case, the boring operation and the injecting operation for installing the outer injection tube can be performed separately. Further, the inside of the outer injection pipe can be re-bored and re-injected, and the injection can be reliably carried out at every injection depth, and the tensile force of the outer injection pipe can be applied to the ground, and the pile effect can be obtained.

  Moreover, the ground which consists of an alternating layer of sandy soil and clay soil can be improved by using together this invention injection material and solution type | mold injection material. This viscous soil was not able to infiltrate with solution type grout, so suspension type grout with high gel strength was injected into vein, but its effect was uncertain because it could not be injected within the specified range. was. However, the above-mentioned injection tube is used to perform compaction injection with a plastic grout on the impervious soil layer, and the permeation-impregnated soil layer can be improved with a solution-type grout. For example, if the ground injection material is injected after solution type grout is injected, the entire ground can be improved.

  Thus, as described above, in the invention of this application, the main ground injecting material injected into each drilling hole 4 performs a pressure dehydrating action on the side of the ground 3 to prevent upward deviation. Therefore, although it is difficult for the ground to be raised, a level detection method using a level sensor is used as shown in FIG. 3 in order to measure the amount of deformation on the ground surface and between adjacent holes. As shown in FIG. 3, a laser beam sensor 15 is provided to the laser beam generating device 11 via a laser receiving device 12 provided on the ground surface of the ground part or a position affected by the injection of the building.

  Then, through the receiving device and the computer 17, the injection control device 18 appropriately adjusts the transfer of the injection stage to the injection tube 9, the injection amount of the injection of the ground injection material, the interval time, the specific gravity and the like as shown in the figure. To control. At this time, the receiving device 12 is displaced up and down with respect to the laser beam sensor 15 in which the laser beam generated from the laser beam generating device 11 is precisely produced, and the uplift of the ground 3 is accurately detected. Then, an injection control device (not shown) is started and stopped via the computer 17, and injection is performed at the optimum timing and amount for the consolidation and dehydration of the side ground of the main ground injection material to be intermittently injected to measure the ground uplift and the like. However, the injection is optimally performed such as stopping the injection, adjusting the injection amount, and moving to another injection point.

  As shown in FIG. 3, laser beam is used for measurement detection such as lateral displacement of the compacted body of injection and ground uplift, and precise measurement in mm is required for optical detection. is there.

  Accordingly, the displacement of the drilling hole 4 and the bulge of the ground 3 can be measured accurately over a wide range, and a minute displacement such as the displacement of the ground 3 can be accurately detected and the strength of the ground 3 as designed. Improvements can be made.

  Thus, in the above-described embodiment, it is basically possible to improve the strength of the ground 3 through the consolidation dehydration action on the side ground 3, but the injection site of the ground injection material to the ground 3 is possible. In order to eliminate potential causes such as liquefaction phenomenon, the moisture in the ground 3 may escape to the other and increase the fluidity of other ground 3 parts. In order to forcibly dispose the moisture in the ground 3 that is removed along with the injection, a drain material such as a paper drain or sand drain (through drainage and soil layers with different drainage properties) is provided together with the compaction action. The dehydration action can be performed positively over both.

  FIG. 4 shows a plurality of outer holes in a borehole obtained by bending to the ground to be improved, boring with any combination of flexure and straight line, or horizontal boring from the pile to the foundation of the building. Install an outer pipe with a pipe discharge port, insert the inner pipe into this outer pipe movably, and inject this ground injection material into the ground from the inner pipe and outlet through the outer pipe discharge port As a result, the supporting ground under the existing structure, which is difficult to be injected, can be injected quickly, reliably and economically to prevent subsidence or liquefaction of the ground during an earthquake. Can be prevented.

  FIG. 4 (a) is a basic schematic diagram of the ground treatment to be improved directly under the structure. As shown in FIG. 4 (a), bent from the ground surface near the ground to be improved directly under an immovable structure such as a building, a waste disposal site, a reservoir, a reservoir, or the like, or into the ground Boring holes are formed by combining bending and straight lines. Next, a plastic injection material is press-fitted from an injection tube provided in the borehole.

  FIG. 4B is an example of ground injection below the structure, and a plurality of layers can be laminated in the depth direction below the structure.

  Next, FIG. 5 shows another embodiment in which the invention of this application is to be carried out. Fig. 5 (a) shows a case where a tubular body such as a casing is provided in the ground and a tensile material such as a reinforcing bar is inserted, the casing is pulled out while being pressed into the ground injection material, and a solid aggregate is formed in the ground. In addition to compressing and strengthening the surrounding ground, this is a mode in which composite ground reinforcement with a pile body that is also effective as a compression pile or tensile pile is intended. Fig. 5 (b) is a pile foundation by press-fitting plastic injection material. Fig. 5 (c) shows a mode of anchor formation by a plastic injection material on the earth retaining wall. 5 (b) and 5 (c) may use the method of FIG. 5 (a), or the effect of the outer tube as a tensile material by injecting from the inner tube using an outer tube having a tensile force. May be given.

  As the injection management method of the present invention, the injection status from the mixing of the ground injection material to the injection into a plurality of injection points in the ground through the injection material feeding system is displayed on the screen, and the injection management is performed by performing batch monitoring.

  FIG. 6 is a flow sheet showing a specific example of the injection management method used in the implementation of the present invention. The centralized management device X1 performs batch monitoring and management of the injection status, and the status is always in the injection monitoring panel X2. Is displayed on the screen.

  FIG. 6 will be described with reference to FIG. 7 showing an operation flowchart of the centralized management apparatus X1. First, an injection specification file is previously set in the central management system X1 according to the injection purpose and injection conditions (system specification setting registration), and then the start switch of the central management device X1 is turned on to start data recording. At this time, the injection monitoring panel X2 is also turned ON by a lamp, and injection data is displayed on the screen. The injection specification file referred to here is the amount of material blended, the specified flow rate of the grout (appropriate flow range), the specified pressure value (appropriate pressure range), the specified injection amount (appropriate integrated injection range), that is, desired The flow characteristics of the grout, injection pressure, flow rate (flow rate per unit time and / or integrated flow rate), and the like. In the above, an appropriate range of ground uplift may be added.

  In accordance with an instruction from the central control device X1, water and powder material are supplied in a fixed amount from the water tank 4 provided with the measuring device 23 and the hopper 25 storing the powder material to the mixer 27, and are mixed by stirring. In addition, when adding the gelation accelerator at this time, the gelation accelerator is added from the hopper 26 for storing the gelation accelerator via the measuring device 23.

  The grout sufficiently mixed in the mixer 27 is subjected to flow measurement by a flow characteristic measuring device 28 attached to the mixer 27 or separately provided, and the result is displayed on the injection monitoring board via the central control device X1. The The flow characteristics shown here are determined by the grout flow, slump, gel time, viscosity, shear strength (cone penetration measurement or the like is used), and the like. When the predetermined fluidity is obtained, the blending is completed, and the grout is further fed from the mixer 27 through the conduit 29 to the grout pump 30. In addition, when the predetermined fluidity is not obtained, the material (water, the granular material, or the gelation accelerator) is added again according to the instruction of the central control device X1, and this is the predetermined flow characteristic. Is repeated until is obtained.

  Here, it is also possible to take out the grout directly from the mixer 27, and it is possible to actually confirm the fluidity manually without using the flow characteristic measuring device 28 and the central control device X1.

  The grout sent to the grout pump 30 is transferred to the injection process. In response to an instruction from the central control device X1, the valve 5 is opened, and the grout pump 30 pressurizes the grout with a desired pressure. The pressurized grout is injected and press-fitted into the ground 3 through the conduit 29 ′, the injection hose 31 and the injection pipe 9.

A pressure gauge p ₀ and a flow meter f ₀ are attached to the conduit 29 ′, and the measured injection pressure and flow rate (flow rate per unit time and / or integrated flow rate) are transmitted to the flow pressure control device 32 and concentrated. Managed by the management device X1.

  Injection is interrupted if the injection pressure and flow rate are not a preset pressure regulation value (appropriate pressure range) or prescribed injection amount (appropriate integrated injection amount range), or if the ground uplift is greater than the appropriate range. Or an instruction for adjustment and control is transmitted by the centralized management apparatus. In addition, since the data is always displayed on the injection monitoring board, the injection conditions can be changed or the emergency injection can be stopped according to the injection status.

As the flow meter f ₀ , an arbitrary flow meter such as a rotary flow meter or an electromagnetic flow meter can be used, and an electric signal output as a pulse is input to the centralized management device X 1 via the flow pressure control device 32. And counted. Controlling the each shunt amount and injection pressure by adjusting the rotational speed of the grout pump 30 in accordance with an instruction from the flow meter f ₀ and / or the central control device X1 based on information from the pressure gauge p _0.

  Further, the central control device X1 controls the flow rate by adjusting the rotational speed of the pump with an inverter.

  Grout pump 30 may be a pump having an inverter or a continuously variable transmission, or a pump having a return device. The inverter and the continuously variable transmission can directly adjust the flow rate and set it to a predetermined pressure value without receiving an instruction from the central control device X1. The return device can also be adjusted directly to return the pressure in the conduit 29 'to maintain the desired pressure. The above adjustment may be performed manually.

  A compressor may be used instead of the grout pump 30. The grout from the mixer 7 is first provided with a pressurized container and filled therein, and then the grout in the pressurized container is pressurized by the operation of the compressor to form a pressurized injection grout.

  A valve 5 is attached to the injection pipe 9, and this valve 5 is automatically opened and closed by an electrical signal from the central control device X1. Using a plurality of injection pipes 9, simultaneous injection from a plurality of injection points 22 in the ground 3, continuous injection, interval injection, or a combination thereof is performed. The valve 5 can be manually closed when the injection is completed.

  After all injections are completed, turning off the start switch of the central management device X1 ends the data recording by the central management device X1.

  The data from blending to injection is sent to the central control device X1, and the injection status is monitored by displaying the screen on the injection monitoring board X2, and the flow characteristics of the grout, the injection pressure of the liquid delivery system, and the flow rate are determined in advance. Inject while maintaining the range and complete, stop, continue or reinject.

  In addition, by installing a gelation promoting material branch valve 34 that is automatically opened and closed in accordance with an instruction from the central management device X1, the mixing time of the gelation accelerator is managed. The time of addition of the gelation accelerator is registered in advance in the system specification settings, mixed in the mixer 27, added before feeding to the grout pump 30, and pumped from the grout pump 30 via the gelation accelerator pump 35. It is also possible to add a gelling accelerator to the finished grout.

  In FIG. 6, the injection method used in the present invention is provided with a flow characteristic measuring device 28, a flow pressure control device 32, a ground (or structure) displacement measuring device, or a valve 5 that can be automatically opened and closed. It is characterized in that it is connected to the management device X1 and the data is displayed on the injection monitoring board X2. The injection monitoring board X2 includes “hour data” such as injection date, injection time, “grout data” such as material blending amount, grout properties, injection block number, injection hole number, injection point, etc. “Injection data” such as “location data”, injection pressure, and flow rate (unit time flow rate and integrated flow rate) are displayed. In addition, injection liquid identification data and ground (or structure) displacement data can also be displayed.

  FIG. 8 shows, for example, liquid feeding system data (a total of 40 data of flow rate, pressure, integrated flow rate, and maximum pressure) at the time of injection having 10 liquid feeding systems on one screen on the injection monitoring panel X2. Shows the screen. The screen of FIG. 8 will be described in detail as follows.

Upper two screens:
Group 1: No. 1 to No. 5 integrated flow rate, maximum pressure digital display Group 2: No. 6 to No. 10 integrated flow rate, maximum pressure digital display The integrated flow rate is an injection amount for 20 minutes. The maximum pressure was displayed every 30 seconds, and the maximum value from 19 minutes 30 seconds to 20 minutes was displayed. If the maximum pressure continues to be higher than the set pressure, it is judged that the injection of the liquid delivery system is finished. Further, when the integrated flow rate reaches the set integrated flow rate, it is determined that the injection of the liquid feeding system is finished.

Lower half 2 screens:
Group 3: Flow and pressure trend display of No. 1 to No. 5 Group 4: Flow and pressure trend display of No. 6 to No. 10 The left side of each of the two screens is an instant corresponding to the passage of time (t) in each liquid delivery system A chart of flow rate and instantaneous pressure is shown, and the right side shows average instantaneous flow rate (l / min) and average instantaneous pressure (MPa) from 19 minutes 30 seconds to 20 minutes.

  In this way, as shown in the screen of FIG. 8, the liquid feeding states of the liquid feeding systems No. 1 to 10 are simultaneously displayed on the injection monitoring panel X2, but the screen is switched for each liquid feeding system. Can also be displayed. The set pressure, the actual pressure, the liquid supply flow rate, and the integrated liquid supply flow rate in the flow rate pressure control device 32 may be displayed on the same screen or different screens. Thereby, the relationship between the pressure and the flow rate can be grasped in real time, and the injection can be managed so as to be within a predetermined setting range. Further, in FIG. 8, pressure and flow rate may be displayed instead of the maximum pressure. Furthermore, the centralized management apparatus X1 can also create forms such as injection specification files, injection result lists, injection charts, daily tables, weekly tables, monthly tables, and analysis data.

  The injection specification file is an operation setting file of the centralized management device X1, and sets the specified pressure value and the specified injection amount for the injection completion condition of the injection liquid feeding system. Each form file is converted and created from the registered flow rate, pressure, integrated flow rate or maximum pressure data and data such as manual input or automatic input of hole numbers. Furthermore, analysis data is converted and created from each form.

  In the screen of the injection monitoring board X2 in FIG. 8, one for each liquid delivery system, for example, for each injection point in the injection hole shown in FIG. , Injection hole No. , And stage no. At the same time, pressure, flow rate, and chart can be displayed.

  Further, from these data, for example, the block No. of FIG. 1, injection hole No. If 3 is displayed, as shown in FIG. 10, the injection pressure P, the flow rate Q, and the integrated flow rate with respect to time t can be displayed for each stage. In addition, by displaying these three-dimensionally as shown in FIG. 11, the allowable injection pressure assumed from the N value and soil cover pressure at each stage, the range, and the allowable injection amount assumed from the target N value are used as a reference. Set. From the injection amount at each injection stage, the ground improvement effect corresponding to the target N value after injection can be predicted in real time from the N value data before injection, and the flow rate is controlled.

  In this way, liquid feeding is injected with a predetermined flow rate or set pressure of the pressure injection grout, or with a flow rate or pressure within a limit range. As a result, it is possible to reliably and predict the improvement effect. The set pressure and the set injection amount can be corrected in consideration of the test injection data.

  EXAMPLES Hereinafter, although this invention is described concretely based on an Example, this invention is not limited by these Examples.

Materials used
(1) Slag Blast furnace slag, 8000 brane value
(2) Cement Ordinary Portland cement: PC, hardened material
(3) Slaked lime Industrial calcium hydroxide, gelling accelerator and curing agent
(4) Gypsum Hemihydrate gypsum, hardening material
(5) Fly ash Coal ash discharged from thermal power plants, density 1.9-2.3g / cm ³ , particle size distribution 0.1mm or less is 90% or more
(6) Bentonite water retention and thickening material
(7) Sulfuric acid band Aluminum sulfate, Al ₂ O ₃ = 17.2%, gelation accelerator
(8) Water glass
JIS No. 3 water glass, SiO ₂ = 29.0%, Na ₂ O = 9.0%, molar ratio 3.3, gelation accelerator
(9) Foaming agent Pre-foaming air generating agent
(10) Aluminum powder Post foaming air generating agent

Formulation Examples 1-3
Mix slag, cement and water. The blending amount of slag and cement was similarly changed only the blending amount of water. Table 2 below shows the adjustment conditions and physical property values of the ground injection materials of Formulation Examples 1 to 3 thus obtained.

  In Table 2, the gelation time refers to the time until the plastic gel is formed after blending, and the time when the table flow becomes approximately 20 cm is defined as the gelation time. The plastic holding time refers to the time during which a gel-like state is maintained if it is stationary, but is in a state of flowing when a force is applied.

Formulation Examples 4 and 5
Mix slag, cement and water. The amount of water blended was the same as in Formulation Example 1 above, and the blending amount of slag and cement was changed. Table 3 below shows the adjustment conditions and physical property values of the ground injection materials of Formulation Examples 4 and 5 thus obtained.

  From Table 3, as the ratio of cured material increases, the breathing rate increases, the plasticity retention time becomes extremely short, the initial viscosity also increases, and the water-to-powder ratio decreases rapidly due to dehydration, so that the vein is split and injected. Cheap. Therefore, the ratio of the hardening developing material is less than 50%, and when cement is used as the hardening developing material, it is preferably 1 to 40%, more preferably 1 to 20%, and most preferably 1 to 10%. In the present invention, blast furnace cement, alumina cement, early-strength cement, slag cement, or any other cement can be used without using Portland cement.

Formulation Examples 6, 7
A sulfate band was added to Formulation Examples 1 and 2 in Table 1 to promote gelation. Here, to promote gelation means to shorten the time until the plasticity is exhibited after blending or to reduce the flow. Table 4 below shows the adjustment conditions and physical property values of the ground injection materials of Formulation Examples 6 and 7 thus obtained.

  From Table 4, it can be considered that by adding a sulfuric acid band, the gel time is shortened, but the plastic holding time is not so much reduced, and the breathing rate is also reduced, so that the workability as a plastic grout can be improved. However, since the sulfuric acid band has the property of reducing the strength expression, the addition amount is within 2.0%, preferably within 1.0% with respect to the powder.

Formulation Example 8
Mix slag, slaked lime, and water. Slaked lime was used as the hardening developing material, and the hardening developing material ratio or water powder ratio was the same as in Formulation Example 2. Table 5 below shows the adjustment conditions and physical property values of the ground injection material of Formulation Example 8 obtained as described above.

  From Table 5, when slaked lime is used as a hardening developing material, gel time and plastic holding time are shortened and strength development is remarkable as compared with blending using cement. When slaked lime is used as the hardening developing material, the hardening developing material ratio is less than 50%, preferably 1 to 40%, more preferably 1 to 20%, and most preferably 1 to 10%. Furthermore, the water powder ratio is 20 to 200%, preferably 40 to 150%.

Formulation Examples 9 and 10
Mix slag, plaster and water. Gypsum was used as the curing expression material, and the ratio of the curing expression material or the water powder ratio was the same as in Formulation Example 2. Table 6 below shows the adjustment conditions and physical property values of the ground injection materials of Formulation Examples 9 and 10 thus obtained.

  From Table 6, when gypsum is used as a hardening developing material, the reaction with slag is poorer than that of cement and slaked lime, so that the gel time and the plastic holding time are long, and the strength development is also slow. When gypsum is used as the hardening developing material, the hardening developing material ratio is less than 50%, preferably 2 to 40%, and the water powder ratio is 20 to 200%, preferably 30 to 150%. Further, a reinforcing material can be added, or cement and slaked lime excellent in strength development can be used in combination.

Formulation Examples 11 and 12
Mix slag, fly ash and water. Fly ash was used as a hardening developing material, and the hardening developing material ratio or water powder ratio was the same as in Formulation Example 2. Table 7 below shows the adjustment conditions and physical property values of the ground injection materials of Formulation Examples 11 and 12 thus obtained.

  From Table 7, when fly ash is used as a hardening developing material, since the reaction with slag is poor compared to cement and slaked lime as with gypsum, the gel time and plasticity retention time are long, and therefore the strength development is also slow. When fly ash is used as the hardening developing material, the hardening developing material ratio is less than 50%, preferably 2 to 40%, and the water powder ratio is 20 to 200%, preferably 30 to 150%. . Further, a reinforcing material can be added, or cement and slaked lime excellent in strength development can be used in combination.

Formulation Example 13
Mix slag, slaked lime, bentonite and water. Bentonite is added with reference to Formulation Example 8. Table 8 below shows the adjustment conditions and physical property values of the ground injection material of Formulation Example 13 obtained as described above.

  From Table 8, by adding bentonite, the viscosity increases and the gel time increases, but the plastic holding time increases and the strength development also decreases. In addition, bentonite exhibits not only a thickening material but also an effect as a water retaining material, so that breathing is reduced and the grout is difficult to be diluted with water. The amount of bentonite added is within 40%, preferably within 30%.

[Factors and conditions as plastic grout]
(1) Curing material ratio Content of powders contained in grout, that is, content of curing material with respect to the content of slag and curing material: Curing material weight / (Slag weight + Curing material weight) x 100 [%]
The slag reacts with calcium contained in the hardening developing material to obtain consolidated strength. However, when the compounding amount of the curing developing material is large, the characteristics as a plastic grout are deteriorated. That is, since the precipitated and increased breathing and the precipitated material hardly flows and does not easily become a plastic gel, the ratio of the cured material is less than 50%, but a preferable range is cement or slaked lime as the cured material. When used, it is 1 to 40%, preferably 1 to 20%, more preferably 1 to 10%. Moreover, when using gypsum or fly ash as a hardening expression material, 2 to 40% is preferable.

(2) Water-powder ratio Water content with respect to the powder in the grout: water weight / (slag weight + cured material weight) × 100 [%]
When this value is small, it tends to be plastic. That is, the time for forming a plastic gel after blending is shortened and the flow value is decreased. However, if the water powder ratio is too small, the workability is impaired. Therefore, the range is 20 to 200%, preferably 30 to 150%. Furthermore, when cement or slaked lime is used as a hardening developing material, 40 to 150% (weight) Ratio) is preferable, and most preferably 120% or less. However, when water glass is used as an accelerator, the water powder ratio can be increased. In addition, since the properties of the grout differ depending on the mixing conditions, environment, and materials, the measurement of the breathing rate, flow value, and strength described later is important.

(3) Amount of sulfuric acid band added Amount of sulfuric acid band added to the powder in the grout: sulfuric acid band weight / (slag weight + curing material weight) × 100 [%]
The sulfuric acid band is a gelation accelerator, and when added to the fluid state of the slag and its cured material, it promotes gelation and accelerates the time to become a plastic gel. However, since the sulfuric acid band also has an effect of reducing the consolidation strength, its addition amount is 2.0% or less, preferably 0.1 to 1.0%.

(4) Bentonite addition amount Bentonite addition amount to the powder in the grout: Bentonite weight / (slag weight + hardening material weight + bentonite weight) × 100 [%]
Bentonite is a water retention material and a thickening material, and is regarded as an active ingredient of the grout and contained in the powder in the grout. The bentonite addition amount is within 40%, preferably within 30%.

(5) Gel time Here, it does not mean chemical gelation that is solidified like that found in common water glass grouts, but it loses its fluidity due to its own weight after compounding. The physical gelation time until it becomes a gel is expressed as gel time. Unlike a grout made from a common water glass, it cannot show a clear gelation time. Therefore, when the value became 20 cm or less using the table flow, it was regarded as gelation, and this was defined as gel time.

(6) Plasticity retention time Asphalt penetration test method According to JIS K 2530-1961, static penetration resistance was measured using a penetration cone with a total mass of 230 g, tip angle of 15 degrees, and 36 mm. When exceeding .01 MN / m ² , it became a non-plastic gel and was regarded as consolidated or cured, and the time from gelation to consolidation was defined as the plastic retention time.

(7) Breathing rate After blending, mix the grout thoroughly, then place the grout in a 200 ml graduated cylinder and seal it statically. After 1 hour, measure the amount of breathing water (superior liquid). Ask. (Breathing water volume / measuring cylinder capacity) x 100 [%]
Here, the breathing rate after 1 hour is shown. When the composition has a breathing rate of 10% or more after the lapse of 1 hour, the injected solution is easily separated and easily injected in the form of veins or cracks. Thereafter, the breathing rate further increases as time elapses. Therefore, the blending rate after 10 hours is preferably 10% or less, and preferably 5% or less.

(8) Flow value Based on the flow test (JIS R 5201 table flow), the grouting was subjected to 15 drop motions in 15 seconds and the spread was measured. About 18-19 cm is said to be suitable as the plastic grout, but in the present invention, the fluidity due to its own weight disappeared when the flow value became 20 cm or less, and the gel time was used. The flowable injecting material in the present invention is used in such a composition that the water-to-powder ratio is lowered by pressure dehydration by pouring into the ground and the table flow reaches 20 cm or less.

  The flow by the cylinder is to measure the spread of the grout when a cylinder having a height of 8 cm and a diameter of 8 cm is filled with the grout and the cylinder is removed. Since it can be measured more easily than the above table flow, it is often used in the field. However, since it is simple, an artificial error may occur. FIG. 12 shows the approximate relationship between the table flow and the cylinder flow.

  In such a blend, even if the water powder ratio is large, the water powder ratio becomes 20% or less in the ground due to dehydration and solidifies from a plastic gel through a non-plastic gel.

(9) Uniaxial compressive strength After blending, a well mixed grout was put into a mold having a diameter of 5 cm and a height of 10 cm, cured for one day in a stationary state, and the uniaxial compressive strength was measured.

Formulation Example 14
Mix slag, slaked lime, bentonite and water, and add water glass. 400 ml of the above blending example 13 was blended, and water glass was further added. The preparation conditions and physical property values of the ground injection material of Formulation Example 14 thus obtained are shown in Table 9 below.

(1) Silica concentration SiO ₂ amount in grout SiO ₂ % of water glass × (water glass weight / grouting weight) [%]
According to the experiment by the present applicant, the silica concentration is set to 0.2 to 7.0% in order to plasticize and solidify the grout, although it depends on the blending ratio of other materials. However, when a low molar ratio water glass having a molar ratio of No. 3 water glass or less is used, 3.0 to 7.0% is preferable. Of course, water glass or powdery water glass having a high molar ratio can also be used. An acidic water glass obtained by mixing water glass and acid can also be used as a gelation accelerator. This case is also expressed as water glass in the present invention.

(2) Characteristics and comparison The characteristics of the formulation shown in Table 8 are that gel time can be easily prepared, and that the plasticity retention time is slightly short, but the early strength development is remarkable. Therefore, it is suitable when importance is placed on the expression of early strength. The gel time of A liquid can be shortened by using plastic grout (formulation example 13 in Table 8 above) as A liquid and water glass as B liquid. Further, by kneading the grout well after gelation, the expression of early strength is reduced, but the plastic holding time can be lengthened. Therefore, it is suitable for ground improvement in which the injection body is expanded by injecting the mixture well-mixed after gelation for the purpose of requiring long-time injection or repeated injection at the injection point once injected by interval injection.

Formulation Examples 15 and 16
As the air generating agent, a prefoaming foaming agent and a post foaming aluminum powder were mixed in a suspension of slag and cement. The blending examples 15 and 16 are shown in Table 10 and Table 11.

(1) Foaming agent addition amount When the content of the foaming agent with respect to the cement contained in the grout is the foaming agent weight / (cement weight) × 100 [%], the foaming agent addition amount is 0.5 to 1. .5% (weight ratio of cement) is preferred.

(2) Addition amount of aluminum powder Aluminum powder reacts with alkali such as cement to generate hydrogen gas (foaming). Assuming that the content of aluminum powder relative to the powder contained in the grout is aluminum ratio: aluminum powder weight / powder body weight × 100 [%], an aluminum ratio of about 0.01% is effective.

(3) Characteristics and Comparison of Formulation Examples 15 and 16 The air generating agent has the effect of improving fluidity in addition to reducing the density of the consolidated body.

  The field injection experiment of the present invention was conducted. The blending solution uses the blending examples shown in Table 12, and the target ground is sandy ground having an N value of 7, a relative density of 40%, and a fine particle content of less than 20%. As a comparative example, Comparative Example 1 of a conventional water glass suspension type instantaneous setting compound (hereinafter referred to as an instantaneous setting compound) is an instantaneous setting (gelation time 10 seconds, no plastic holding time), and Comparative Example 2 is an LW. (Gelging time 1 minute, no plastic holding time). The formulations of Comparative Example 1 and Comparative Example 2 are shown in Table 13 and Table 14, respectively. Examples using the formulation example of Example 1 are shown in Table 12. A to F are also shown for the mixing of the mixture, the formation of the plastic gel, and the press-fitting situation. The consolidation status in the excavation survey is shown in I-VI.

  As shown in Table 12, in the case of press-fitting according to Category A, when blended and mixed in a mixing apparatus and then press-fitted as plastic gel until it became impossible to press-fit, a substantially spherical solid body formed of a plastic gel was formed. The growth of the gel-like lump forms a lump having a large plastic-retaining time and a high water / powder ratio and a high ratio of the cured substance.

  In the press-fitting according to the section B, the injection is started before the plastic gel is formed in the mixing process of the composite device and reaches the plastic gel in the injection process. Although it was indefinite, a massive solid body was formed within the injection target range. This is because the liquid mixture with sufficient fluidity in the initial stage of press-fitting is pressed in a direction where the press-fitting resistance of the ground is small and weak, and the fluidity decreases with dehydration. Seems to have expanded and solidified. In this case, even if it is not a spherical body, it is compacted around a weak portion, so that the improvement effect can be sufficiently obtained even if it becomes indefinite.

  In the press-fitting according to section C, the plastic gel is not reached until the press-fitting of the stage is completed during the mixing process, but the pressure rises with the press-fitting time, and finally the injection amount becomes zero and the injection becomes impossible. In the investigation of the excavation results, the fluidity is high at the beginning of the injection, so it is partly split and injected to the outside of the handling range, but the fluidity is lost due to dehydration in the ground and the plastic gel is within the handling range. The lump gel grows greatly with the formation, and the effect of compressing and strengthening the surrounding ground is obtained.

  In the injection by section D, it is a normal water glass grout with no plastic holding time after gelation, and the pressure increases with gelation. Consolidate into a shape. For this reason, there is almost no effect of increasing the density of the target ground.

  The injection according to the section E is a compounded liquid that does not exhibit a general plastic state, and does not show an increase in pressure while maintaining the initial pressure during injection, and deviates outside the injection target range and hardly improves.

  In the press-fitting according to the section F, the fluidity is already very low at the time of injection into the ground, so dehydration occurs immediately outside the discharge port as soon as it is discharged from the injection tube discharge port, and then the inside of the discharge port It was found that the dehydration phenomenon of the injection material occurred, and as the pressure was further increased, the injection material in the injection tube dehydrated upward in the injection tube and finally the entire injection tube solidified and became unable to be injected.

  Injecting a plastic grout with low fluidity into the ground in this way resulted in the phenomenon that no matter how much the pump pressure was raised, no injection was possible and no crack injection occurred. Such a phenomenon is also a phenomenon that occurs when a plastic gel less than the slump 5 is injected by mixing the powder injection solution and the plastic material before flowing into the injection tube.

  In categories A, B, and C, the volume of the consolidated body and the injection amount were measured in the excavation survey after injection, and the dehydration amount was within about 30%. It turned out that a block gel is easy to be formed if it press-fits into the ground of the composition whose composition liquid turns into a plastic gel by 30% dehydration. In other words, it was found that if the injection material in the above flow range was pressure dehydrated until it became uninjectable and pressed into the ground, a solid gel that could not flow with a dehydration rate of approximately 30% or less was formed in the ground. From various field injection experiments including these phenomena, the compounded liquid at the time of injection reaches the plastic gel at the time of injection, or even if it does not become a plastic gel at the start of injection If the composition is set so that the plastic gel is reached before it is injected into the ground, or the plastic gel is formed during the injection by dehydration within 30% of the composition liquid It was found that a bulk gel was formed therein.

Table 12 is an example of the improvement effect in the ground where the N value is 10 or less. For example, in the case of compounding example 3, for 5 minutes after compounding, the discharge rate is 5 l / min per minute, the initial pressure is 1.0 MN / m ² , the maximum diameter pressure is 3.0 MN / m ² , and the injection speed is zero. It became impossible to press fit. As a result of excavation investigation with a total injection volume of 150 liters, it was found that a bulk gel of approximately 100 liters (dehydration rate of 30%) was formed.

  The plastic gel press-in method is a press-fit of a plastic gel whose fluidity decreases in the ground, so it is intended for loose ground that can be press-fitted with pump pressure, and usually has an N value of 15 or less, most preferably N value Is 10 or less soft ground. However, in order to prevent liquefaction and to reinforce the foundation, the ground having an N value of 15 or more or 20 or more may be further improved. For such ground conditions and purposes, the present inventor has found that the methods according to the sections B and C of Experiment 2 are extremely effective in several field injection tests.

In such a ground, when compounding example 3 is injected as in section A, the injection pressure rises after injection and it is difficult to obtain a large lump gel, or after mixing compound example 2 for 3 hours, the discharge rate is 5 l / min. When min was injected at an initial pressure of 0.1 MN / m ² , the pressure became 1.0 MN / m ² after 5 minutes, and the total pressure was 50 l at a final pressure of 3 MN / m ² . Partial cracks were observed in the leading part of the solidified solid body, and a large solidified body having a large thickness centered on the crack on the center side was formed.

  That is, when the N-value is 15 or less, the plastic gel grows and expands in the ground at the time of injection, but if the N-value of the ground is 15 or more, it is difficult to continue to press-fit with the plastic gel. It becomes. However, by injecting into the ground a compounded liquid that is not a plastic gel in the initial stage of injection, even if the ground has a N value of 15 or more, it splits and dehydrates into a plastic gel while forming a vein-like crack. It lowers and becomes a gel in the crack, and the massive gel expands around the gel and grows into a large massive gel. In this case, although it is not a spherical body, the density of the surrounding ground is increased within the range of handling, and the strength of the ground can be increased.

  Such a result is that the ground density is high in order to press-fit the plastic gel by injecting the plastic gel by switching to the press-fit of the plastic gel after injecting cracking by injecting a liquid composition with good fluidity at the initial stage of injection. It was found that this is an extremely effective means for ground improvement that requires ground improvement. Similarly, it is possible to reinforce the ground with a density that is difficult to press by alternately injecting a liquid mixture with good fluidity and a plastic gel, and expanding the bulk gel in a predetermined area while repeating the pressure of the crack injection block gel .

  In this way, the conventional cement grout and LW grout only deviate in a pulse shape. However, the injection of the injection material that reaches the plastic gel or the injection material of the plastic gel in the middle of the plastic grout can be performed. It has been found that the scope of application of the gel gel press-in method greatly expands.

As a specific method and mixed by selecting the kind and amount of fluidity-adjusting agent while injecting a plastic gel or more plastic-like gel obtained by mixing the fluidity controlling agent as an active ingredient the S material and material C It is possible to inject a combination of an injection material with good fluidity and an injection material with low fluidity, or a plastic with addition of an injection material or fluidity adjustment material with good fluidity as A liquid. Crack injection lump press-in can be combined with a method in which fluidity adjusting materials are joined and injected while injecting a gel-like gel.
Field injection experiment

Explanation of consolidation status in Table 12 Shape of consolidated bodies in excavation survey I Formation of large massive solid bodies of approximately spherical shape with a diameter of 30 to 70 cm
II The shape is not spherical but irregular, but formed into a solid aggregate with a diameter of 20-50cm
III Although some of the tips were pulsated outside the injection range, the diameter was 20 to 50 cm within the range.
Massive solid body formation
IV 1-10cm thick vein
Deviation outside the injection range V Thickness 1-5cm
Deviation out of injection range
VI Only the size of the injection hole

  As a result of the research by the test construction shown in FIG. 1 in the present invention, it was found that the ground reinforcement effect can be obtained by the injection design as follows.

In FIG. 1, the injection interval is 0.5 to 3.0 m. The improvement rate is 5 to 40%. Here it corresponds to the cross-sectional area of the conversion to consolidated mass and improved rate allocation improvement area 1 m ² per 1 injection hole, the improvement ratio 5-40% means 0.05~0.4m ^2. In addition, this improvement rate is calculated from the reduction amount of the gap in the receiving area per hole from the N value of the improvement target ground and the improvement target N value, and the reduction amount corresponds to the area to be replaced by the gelled product. Is calculated from Table 17 shows design examples effective as ground reinforcement in the present invention. This is based on the experimental example performed on the sand ground in Example 2, the injection arrangement is a square arrangement shown in FIG. 1 (b), the injection interval is 1 m, 2 m, and the improvement rate is 5%, 10%, 15% and 20%.

  It is necessary to set the injection rate (l / min) and the injection pressure per minute so that the injection amount calculated in this way falls within a predetermined depth. For this purpose, it has been found that it is desirable to perform injection while controlling injection at a discharge rate of 5 to 50 l / min per minute and an injection pressure of 0.5 to 10 MP.

  At this time, it was found that if the ground uplift is within 20 cm, preferably within 10 cm, the gel in the ground will be within about 5-10 cm due to dehydration after several days.

  In addition, it was found that when the implantation depth was GL 3.0 m or less, the ground was slightly raised, and when the GL was 1.5 m or less, it was raised to 10 cm or more. Accordingly, it has been found that it is effective to take measures corresponding to the ground uplifting at a depth of 3.0 m or less, or 1.5 m or less, that is, the measures of claims 30 to 36. Further, it has been found that the ground improvement effect is possible only when the ground is compressed by being pressed into each other by press-fitting from a plurality of holes in the range of the injection hole interval.

  The present invention is a method in which a specific plastic gel injection material is press-fitted into the ground and the soil particles are pushed to the periphery while forming a lump of plastic gel in the ground by elapse of time or by pressure dehydration, Since it is intended to strengthen the ground by forming a lump of plastic gel injection material itself in the ground, it can be used in the civil engineering and construction field.

It is a model figure of ground reinforcement by plastic grout press-fitting, (a) is a cross-sectional view of column connection showing the arrangement of consolidated bodies by plastic grout in the area to be improved, (b) and (c) are plan views and plastic injection material FIG. (B) is a square layout, and (C) is a triangular layout. (a) is a cross-sectional view of a state of pull-up injection from the bottom to the top by a rod injection tube of plastic gel drilled adjacent to the ground of a predetermined area, (b) is adjacent to the ground of the predetermined area It is a cross-sectional view showing an example in which an outer injection pipe is installed and a plastic gel is press-fitted from the injection inner pipe, and is a cross-sectional view of a press-fitting mode by an interval method while switching the valve 5 from one pump, (c) is a cross-sectional view showing the effect of reinforcing the injection tube tensile strength by a high density body of solid ground by forming a solidified body with a plastic gel at intervals between predetermined installations of the injection tube having tensile strength. It is. It is a schematic diagram of the displacement measurement aspect in the middle of construction of the ground. (a), (b) is a basic schematic view and a cross-sectional view of the seismic reinforcement injection just under the structure. (a) is a schematic diagram of press-fitting of a plastic gel by inserting a reinforcing bar into a drilled casing and pulling out the casing. Since the plastic gel does not deviate, the surrounding ground is consolidated to form a grout pile having a large strength. . (b) is a cross-sectional view of ground reinforcement of a pile foundation by plastic grout, and (c) is a cross-sectional view of anchor formation by press-fitting of plastic grout in the retaining wall. It is a flow sheet which shows one specific example of the injection | pouring management method until mixing of the material in this invention and injection | pouring of grout. It is the flowchart of the mixing | blending and injection | pouring which operation of a centralized management apparatus and the centralized management system manages. It is an example of the screen display which represented the integrated flow volume and the maximum pressure about 10 liquid feeding systems, and the flow volume and the pressure on the injection | pouring monitoring board using the centralized control apparatus. The four injection block sections No. It is an example of the screen display which expressed 1-4 on the injection | pouring monitoring board. Ground stage No. It is the graph (chart) which represented the flow volume and injection | pouring pressure in 1-3 on an injection | pouring monitoring board. It is an example of a three-dimensional display of the injection amount or the injection pressure. It is a graph showing the relationship between a table flow and the flow by a cylinder.

Explanation of symbols

3 Ground 4 Drilling hole 5 Valve 6 Controller 7 Computer 8 Casing 9 Injection pipe
10 Rebar
11 Laser beam generator
12 Laser receiver
14 Footing
15 Laser beam sensor
16 Steel pipe injection pipe
17 Computer
18 Injection controller
19 Reinforced support pile
20 Pile foundation
21 Earth retaining wall
22 Injection points
23 Weighing scale
24 water tank
25 Hopper
26 Gelling accelerator hopper
27 Mixer
28 Flow characteristics measuring device
29 conduit
29´ conduit
30 grout pump
31 Injection hose
32 Flow pressure controller
34 Gelation accelerator branch valve
35 Gelling accelerator pump
36 Level sensor X1 Central control device X2 Injection monitoring panel f ₀ Flow meter p ₀ Pressure gauge

Claims (13)

The plastic gel injection material is press-fitted through a plurality of injection holes provided in the ground, and the ground soil particles are pushed around while forming a lump in the ground to form a plurality of lump in the ground. A ground strengthening method for increasing the density of the ground around the plurality of injection holes and strengthening the ground,
The plastic gel injection material is
(1) Slag (S material)
(2) Powdery hardening material (C material) selected from the group consisting of cement, fly ash, lime and gypsum
(3) Water (W material)
Sac Chi comprises as an active ingredient (1) and (2) (3),
The plastic gel injection material has a table flow of 12 cm or more and less than 30 cm at the time of press-fitting, and / or a slump of greater than 5 cm and less than or equal to 28 cm, and / or a cylinder flow of greater than 8 cm and less than 28 cm, and press-fitting into the ground It is an injection material that reaches the plastic gel before or during press-fitting, reaches the plastic gel within 30% of the dehydration rate, loses fluidity due to dehydration in the ground, forms a lump, and is equivalent to or higher than the surrounding ground A ground strengthening method characterized by being an injection material that develops the strength of the ground. The ground strengthening method according to claim 1 , wherein a ratio of the cured material of the plastic gel injection material is 1 to 40 percent by weight.
However, hardening expression material ratio = C / (S + C) × 100 (%), and S and C both indicate weight. The ground strengthening method according to claim 1 or 2 , wherein a water powder ratio of the plastic gel injection material is 20 to 200 weight percent.
However, the water body ratio = W / (S + C) × 100 (%), and S, C, and W all indicate weight. 4. The fluidity adjustment according to claim 1, 2 or 3 , wherein the plastic gel injection material comprises a gelling accelerator, a gelation retarder, a thickener, a water retention material, a peptizer, a foaming agent, or a fluidizing material. Ground strengthening method including materials. The plastic gel according to any one of claims 1 to 4, wherein an injection tube is installed in the ground to be improved, and the plastic gel is passed through the injection tube while moving the injection tube upward or downward to move the press-fitting stage. A ground strengthening method in which an injection material is pressed in to form a massive solid body in the ground. 6. The ground strengthening method according to claim 5, wherein the step of pulling up the injection tube is stepped up so that the discharge port is positioned within the range of the block before solidification, and the block is expanded and press-fitted. 7. The ground strengthening method according to claim 5, wherein the interval between the injection holes is 0.5 m to 3 m and the ground density between the injection holes is increased to strengthen the ground. 8. The ground strengthening method according to claim 5, 6 or 7, wherein the injection amount is 5 to 50 l / min and the injection pressure is in the range of 0.5 to 10 MP by controlling the injection amount and the injection pressure. In any one of Claims 1-8, the hardening expression material added to slag is less than 50 weight% in the powdery raw material to be used, and a water powder contrast is 20 to 200 weight%, and the case where a gelling accelerator is added Is a table flow of 12 cm or more and less than 30 cm by mixing an aluminum salt with an aluminum ratio of 0.1 to 3.0% by weight with respect to the total amount of powder contained in the pouring material, gel time is within 3 minutes to several hundred minutes, The ground characterized in that the plastic holding time is from several hours to 10 hours or more, the breathing rate is within 10%, the slump is greater than 5 cm and less than 28 cm, and the flow through the cylinder is greater than 8 cm and less than 28 cm. Strengthening method. In any one of Claims 1-9, the injection | pouring material of the fluidity | liquidity of the state which is not a plastic gel in the initial stage of injection | pouring and the injection | pouring material of a plastic gel are used together, and it is a split part in the ground with the said fluidity | liquidity injection material. To improve the ground of a density that is difficult to press-fit the plastic gel by forming a solidified body by expanding the split part with the plastic gel injection material and densifying the surrounding ground A ground strengthening method characterized by In any one of 1-10, a blending control device is provided in the blending system of the injection material, a flow rate pressure control device and a flow meter and a pressure gauge are provided in the injection material feeding system, or a ground displacement meter is further provided. The data signals detected from these are sent to a central control unit equipped with an injection monitoring board, and these data are displayed on the injection monitoring board to perform batch monitoring of the conditions from injection material blending to press-fitting. Injecting while maintaining each injection pressure and / or flow rate in the liquid system within a predetermined range, and completing, stopping, continuing, moving the injection point, or reinjecting based on the information of the above data A ground strengthening method characterized. The control device that manages the composition of the injection material, the flow pressure control device that manages the liquid feeding of the injection material, the pressure gauge, and the flow meter in any one of 1 to 10 , and data detected therefrom Is transmitted to a centralized control device equipped with an injection monitoring version, and the composition of the injection material, injection hole, press-in stage, and press-in status are displayed on the screen of the injection monitoring version, and injection monitoring is performed by performing batch monitoring. How to strengthen the ground. In Claim 12 , the injection pressure and / or the flow rate and the injection amount set value, the ground displacement amount, and the allowable range thereof are set in advance in the centralized management device, and the injection management is performed so as to maintain the set range. Ground strengthening method.

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