JP4036303B2 - Ground injection method - Google Patents

Description

  The present invention relates to a method for injecting ground such as soft ground, water leaking ground, ground that may be liquefied, contaminated ground, etc. Or, it is related to the ground injection method below the reservoir or reservoir (hereinafter referred to as “structure”). Specifically, the support ground below the existing structure, which is difficult to perform ground injection, can be quickly and reliably grounded economically. Injecting can prevent land subsidence and liquefaction of the ground in the event of an earthquake, and also prevent the release of harmful substances from the waste disposal site, and also prevent leakage from reservoirs and reservoirs It relates to the ground injection method.

  In a conventional liquefaction countermeasure for a building foundation, for example, as shown in FIG. 1, for example, an injection outer pipe having a plurality of discharge ports bored horizontally below the foundation of the structure 54 is installed. A method is used in which an injection inner tube is inserted into the tube, an injection solution is injected into the ground sequentially from the outer tube discharge port, and the ground is consolidated.

  In many cases, liquefaction prevention works are to improve large-capacity ground directly under existing structures. Therefore, it is necessary to improve the ground economically and reliably. For this purpose, it must be reliably injected into a predetermined region, and the injection must be performed between soil particles at a low discharge rate. In this case, in order to improve the ground, it is necessary to install a long-distance injection tube under any combination of bending and horizontal, and inject it. For this reason, injection takes a long time, and the construction period becomes long and the construction cost becomes high. In order to prevent this, it is necessary to reduce the hole diameter of the injection tube, simplify the injection operation, and increase the construction efficiency. For this purpose, it is possible to inject from a single discharge port at a low discharge rate to infiltrate between the soil particles, and overall, it is possible to inject at a high discharge rate to improve economic efficiency. Conceivable.

  In general, since the ground is composed of layers with different particle sizes and water permeability, when the injection pipe is inserted into the ground and the ground is consolidated through the injection liquid, the injection liquid is permeable to water. The entire layer cannot be consolidated uniformly.

Therefore, a construction method shown in FIGS. 10A to 10D has been developed as means for solving this problem. In detail this, first, as shown in FIG. 10 (a), the ground 1 and boring, inserts the casing 2 in this. Then inserted outer tube 3 into the casing 2 as shown in Figure 10 (b). A plurality of discharge ports 5, 5.. 5 are opened at predetermined intervals on the tube wall 4 of the outer tube 3 at different positions in the axial direction. The discharge ports 5, 5. Covered with.

Further, after injecting the sealed grout 7 to the casing 2, pulling the casing 2 as shown in Figure 10 (c). As a result, the outer tube 3 is sealed with the seal grout 7.

Next, as shown in FIG. 10 (d) , strainers 8, 8,... 8 are drilled at the tip, and the inner tube 10 in which the packers 9, 9 are arranged above and below is inserted into the outer tube 3. When the injection solution is injected through the conduit of the inner tube 10, the injection solution passes through the strainer 8 and the space 11 formed between the upper and lower packers 9 and 9 as indicated by the arrow, and passes through the rubber sleeve 6 from the discharge port of the outer tube 3. It spreads and breaks the seal grout 7 and penetrates into the ground 1 around the stage.

In the construction method shown in FIG. 10 described above, the injected liquid does not deviate in the vertical direction along the outer tube 3 due to the presence of the seal grout 7, and reliably penetrates and solidifies at every predetermined injection depth. In addition, since the different types of work in the drilling and outer pipe embedding process and the injection process can be performed separately, there is also an operational advantage that the operation can be simplified.

  However, in the construction method described above, the packers 9 and 9 of the inner tube 10 are formed of a ring-shaped hard synthetic resin. With such hard packers 9 and 9, the outer tube is deformed by earth pressure when the injection depth is deep, The inner tube 10 cannot be inserted or pulled up. If the packers 9 and 9 are made of a soft material, the packer effect cannot be obtained. For this reason, as shown in Japanese Patent No. 2772637 of the present applicant, a method of simultaneously injecting from a plurality of outer tube discharge ports using an inner tube having a plurality of packers has also been proposed. A synthetic resin is used, and the above problem has not been solved.

  For this reason, a construction method using an air packer shown in Japanese Patent No. 2814475 has been developed instead of a hard packer. However, in this construction method, since the air packer pipe must be formed in the inner pipe, the diameter of the inner pipe is reduced. growing. Therefore, not only the diameter of the outer pipe is increased, but the bore hole for inserting the outer pipe is also thickened, the economy is reduced, and the number of work processes is increased. Therefore, the work process is increased and the construction is complicated. .

  Furthermore, a rubber bag is provided at the tip of the inner tube of the double tube rod, the main material passing through the two channels of the outer tube and the inner tube and the aqueous solution of the reactant are mixed, and the resulting grout with a short gel time is obtained. The applicant has also proposed a construction method in which the grout having a long gelation time and the position of the discharge port are switched and the double tube rod is pulled up and injected. (See Japanese Patent Publication No. 63-64567.)

However, this method involves complicated switching of grouts with different gelation times, and the injection is performed while pulling up the double tube rod. Therefore, if injection at a certain injection depth is incomplete, reinjection ensures reliable injection effect. It is impossible to get. In addition, it is difficult to rationalize the operation because a boring hole drilling process and an injection process, which are different types of processes, must be successively performed for each of a large number of injection holes. Further, in JP-A-7-71028 and JP-A-8-226119, a packer consisting of a bag body or a dumbbell-shaped bag body is attached to the injection tube, and the inner tube discharge port between the packers is injected into the ground through the outer tube discharge port. A construction method has been proposed. However, in any case, the fluid that inflates the packer of the bag body is press-fitted through the flow path for the packer, and is different from the flow path of the injected liquid injected into the ground from the inner tube discharge port. Therefore, the inner pipe diameter to be inserted into the outer pipe becomes thicker because it is composed of separate packer flow path and injection liquid flow path, and therefore, the diameter of the hole for embedding the outer pipe is also increased. There is a problem in terms of sex.
Japanese Examined Patent Publication No. 63-64567 JP-A-1-52910 Japanese Patent No. 2814475 Japanese Patent Laid-Open No. 7-71028 JP-A-8-226119

Upon liquefaction prevention Engineering challenges structure downwardly to be solved, and boring and horizontal or bent, in ground grouting method for injecting an injection fluid from an injection pipe which is installed in the borehole, the pipe diameter of the injection tube By reducing the size and simplifying the structure, the drilling hole diameter (boring hole diameter) is reduced, the workability is improved, the economy is obtained, and the long section can be injected under the structure. Inside the outer tube, the inner tube easily moves to a predetermined injection stage while forming a packer. This allows multiple injections to be repeated many times, or multiple long injection stages can be injected simultaneously. An object of the present invention is to provide a ground injection method that ensures the injection effect and improves the above-mentioned drawbacks of the known technology.

  In order to solve the above-mentioned problems, according to the ground injection method of the present invention, the injection pipe is bent on the ground below the building, or installed horizontally, or any combination of bending and horizontal is installed. In the ground injection method for injecting an injection solution into the ground through the outer tube, the injection tube is loosely inserted into the outer tube and a plurality of inflatable / retractable inner tubes. A tube packer is provided with an interval so as to sandwich the outer tube discharge port, and further, an inner tube packer is provided in the inner tube packer, and an inner tube is provided between the inner tube packers provided with the interval. An injection tube having an inner tube having a discharge port, which is installed in a drilling hole drilled by a boring rod having a built-in position information transmitter at the tip, and sends the injection solution to the inner tube flow path Thus, the inflatable inner tube packer is adjusted to the liquid feeding pressure. The outer tube inner space is formed between a plurality of inner tube packers by expanding, and the injection solution is discharged from the inner tube discharge port into the outer tube inner space, and the injection solution is grounded from the outer tube inner space through the outer tube discharge port. It is characterized by being injected inside.

  In the ground injection method of the present invention, the injection pipe is installed in a boring hole drilled by a boring rod with a built-in position information transmitter at the tip, and consists of an outer pipe and an inner pipe loosely inserted in the outer pipe, This inner pipe expands the inner pipe packer with the feeding pressure of the injection liquid fed to the inner pipe flow path without providing a packer fluid pipe for expanding the inner pipe packer. The inner tube diameter can be reduced by omitting the installation of the inner tube, and the inner tube can be freely redirected into the outer tube and injected at a predetermined stage while omitting the packer operation. There is an effect of obtaining economic efficiency and workability of ground injection.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a basic view of an example of ground injection below a structure. FIG. 2 is a cross-sectional view of a specific example of the method of the present invention. FIG. 3 is a cross-sectional view of another specific example of the method of the present invention. FIG. 4 is a sectional view of still another specific example of the method of the present invention. FIG. 5 is an explanatory diagram for explaining the principle of the packer function of the method of the present invention.

  In the present invention, as shown in the basic view of FIG. 1, a plurality of holes 23 are formed in a depth direction below the structure 54 in a depth direction so as to be substantially horizontal, and an injection pipe (ground) is formed in the hole 23. The injection tube A) is inserted and installed, and the injection solution is injected into the ground 1 through the injection tube A. Specifically, the ground injection pipe A used in the method of the present invention is shown in FIG.

  In FIG. 2, the ground injection pipe A used in the method of the present invention is basically composed of an outer pipe 20 and an inner pipe 21. The outer tube 20 has a plurality of outer tube discharge ports 22 at different positions in the axial direction, is inserted into a hole 23 formed in the ground 1, and a hole 23 between the hole wall 24 and the outer tube 20. The seal grout 25 is filled in and fixed and installed in the ground 1. The outer tube discharge port 22 is covered with a rubber sleeve 26 as shown in FIG. The rubber sleeve 26 functions as a check valve.

  The inner tube 21 is loosely inserted into the outer tube 20, and a plurality of inflatable inner tube packers 27, 27... 27 are spaced apart so that the outer tube discharge port 22 is sandwiched by the fasteners 28, 28. Prepare. Further, the inner tube 21 has a packer discharge port 29 in the inner tube packer 27, and an inner tube discharge port 30 between the inner tube packers 27, 27 provided at intervals.

  The ground injection pipe A used in the construction method of the present invention configured as described above sends the injection liquid to the inner pipe flow path 31 of the inner pipe 21 so that the expandable inner pipe packer 27 supplies the injection liquid. An outer pipe inner space 32 is formed between a plurality of upper and lower inner pipe packers 27, 27 that are expanded by pressure, and an injection liquid is discharged from the inner pipe discharge port 30 into the outer pipe inner space 32. Through the outer tube discharge port 22 from the inner space 32, the rubber sleeve 26 is pushed and expanded, and the seal grout 25 is split and injected into the ground 1. Next, after the filling material is discharged from the inner tube packer 27 and contracted, the inner tube 21 is moved until the inner tube discharge port 30 coincides with the other outer tube discharge port 22, and injection is repeated in the same manner.

  3 is a cross-sectional view showing another specific example of the injection tube A used in the present invention. The outer tube 20 includes a plurality of outer tube packers 33, 33,... 33 so as to sandwich the outer tube discharge port 22. Then, the solidified material is filled into the outer tube packer 33 through the discharge port 34 in the outer tube packer by expanding the rubber sleeve 26, expanded, fixed and installed in the ground 1. Then, the infusible inner tube packer 27 is expanded by the liquid feeding pressure of the infusate by feeding the injection solution into the inner tube flow path 31 and is adjacent to the left and right inner tube packers 27 as in FIG. 27, an outer tube inner space 32 is formed. The injected liquid is further discharged from the inner tube discharge port 30 to the outer tube outer space 35 through the outer tube inner space 32 and the outer tube discharge port 22, and is injected into the ground 1 from here. Further, the inner tube 21 is moved in the same manner as in FIG. 2, and the injection is repeated. Since this outer tube space 35 becomes a columnar injection source having a large surface area, even if it is injected at a large injection rate, since the injection rate from the unit area of the injection source is low, it can be injected between soil particles at a low pressure, and it can be rapidly injected. Osmotic injection is possible.

  The outer tube packer is preferably made of a water-permeable bag and has a diameter sufficient to expand to a diameter larger than the hole diameter by press-fitting a consolidated material into the packer. In particular, the ground subject to application of the present invention that has a risk of liquefaction is a loose layer of fine sand, and its water permeability is greater in the lateral direction than in the vertical direction. For this reason, the injection solution is likely to spread widely in the horizontal direction. In order to prevent this and perform predetermined injection for each stage in the lateral direction, it is desirable to spread the outer tube packer into the soil to form a packer larger than the hole wall. In this way, the soil around the packer is crushed to the periphery, and a part of the consolidated material oozes out from the water-permeable bag body to the periphery, and the packer is larger than the packer formed by the actual bag body. Is formed in the soil. For this reason, a solidified body corresponding to a predetermined injection amount is formed for each predetermined stage without the injection liquid deviating in the lateral direction without limitation.

Furthermore, in the present invention, it is desirable to drill using a drilling liquid containing a hole wall holding material when drilling with a boring rod. A polymer material such as CMC or PVA is suitable as the hole wall holding material. Of course, bentonite can also be mixed in these. These are also lubricants, which not only facilitate the drilling operation in the horizontal boring, but also hold the hole wall even when vertical earth pressure is applied when the boring rod is pulled out. This not only facilitates drawing, but also solves the problem that the horizontal drilling wall collapses by the time it is injected, making injection difficult, and the injection hole wall is held by the adhesive force of the polymer material. Injection becomes easier.

  FIG. 4 is a cross-sectional view of still another specific example of the injection tube A used in the present invention. The inner tube 21 is provided with three or more inflatable inner tube packers 27, 27,. This is an example in which a plurality of 32 are formed. In this case, the injection solution can be simultaneously injected into the ground 1 from the plurality of outer tube discharge ports 22, 22. Thereby, a several injection | pouring stage can be inject | poured simultaneously and rapid construction of a long injection | pouring area is possible. That is, in the present invention, the packer is formed by the injection solution itself, so that a large number of packers can be formed in the inner tube, and therefore, it is possible to inject simultaneously from a large number of outer tube discharge ports.

  In the present invention, as shown in FIG. 6, a plurality of inner pipe flow paths 31 can be provided by providing a plurality of inner pipes 21. In this case, the inner tube discharge ports 30, 30... 30 are opened to different outer tube inner spaces 32. That is, since the present invention forms a packer with the injection solution itself, simultaneous injection by an inner pipe having a plurality of injection pipes is possible. As a result, not only can multiple injection stages be injected at the same time to enable rapid construction of long injection sections, but also injection materials with different permeability and strength can be injected according to the state of the soil layer, and the main material It is also possible to superimpose and inject the reactant on the injection stage in which the solution is injected, or to inject the solution type grout on the region where the suspension is injected. At this time, although not shown, if a plurality of inner pipe discharge ports are opened in the same outer pipe inner space, two types of injection liquids, for example, a main ingredient compounding liquid (A liquid) and a reactant compounding liquid (B liquid) can be obtained. The mixture is mixed in the inner space of the outer tube, and this mixed solution is injected into the ground from the outlet of the outer tube. The plurality of inner pipes may be parallel pipes or multiple pipes.

Furthermore, the inner pipe discharge port 30 is formed so as to satisfy one of the following (a) and (c).
(A) The inner pipe discharge port 30 is formed in a fine hole. This state is shown in FIG.
These pores may be directly drilled into the inner tube 21 with a predetermined hole diameter, but a wear-resistant metal tip (not shown) previously drilled with a pore with a predetermined diameter is provided in the inner tube discharge port 30. It is preferable that the screw is detachably attached. In this case, since the pores of the tip are worn by the injection pressure of the injection solution and can be replaced with a new tip when the diameter becomes large, an accurate discharge speed of the injection solution can always be maintained.
(B) The inner tube discharge port 30 is formed in a smaller pore than the inner tube packer discharge port 29. This state is shown in FIGS. 7 (a) and 7 (b).
(C) The area of the inner pipe discharge port 30 is formed smaller than the cross-sectional area of the inner pipe flow path 31. This state is shown in FIGS. 7 (a) and 7 (b).

  The inner pipe discharge port 30 is covered with a resistor such as a rubber sleeve 26 as shown in FIG. 7 (c), or a check valve 50 is attached as shown in FIG. 7 (d). The check valve 50 is configured such that a ball 51 is applied to the inner pipe discharge port 30 from the outside, and the ball 51 is pressed by a spring 52.

  Furthermore, as shown in FIG. 5, a decompression device 44 can be provided in the inner pipe flow path 31. Further, as shown in FIG. 8, the inner tube 21 may be formed by connecting with a flexible joint. 8A is an example in which one inner pipe is connected by a flexible joint, and FIG. 8B is an example in which a plurality of inner pipes are connected by a flexible joint.

  The inner pipe packer 27 is formed of a synthetic rubber bag body which is impermeable and rich in elasticity. Therefore, when the internal pressure due to the injected liquid acts on the inner tube packer 27, the inner tube packer 27 expands and comes into close contact with the inner wall of the outer tube 20 to form a packer. However, when the feeding of the injected liquid is stopped or the pressure of the injected liquid is reduced by the depressurizing device 44 provided in the inner pipe flow path 31 as shown in FIG. Move away from the inner wall of the tube 20. Therefore, it is possible to immediately move to the next injection stage after completing a predetermined amount of injection at a predetermined stage. The depressurization device 44 only needs to be downstream from the infusion pump, and may be only a valve such as a three-way cock in the figure. When the valve is opened, the injected liquid pressurized in the inner pipe is discharged to the outside, and the inner pipe packer contracts. Furthermore, if the injection liquid in the inner pipe is sucked up by the water absorption pump, it is possible to minimize the leakage of the injection liquid in the inner pipe into the outer pipe when moving the injection stage.

  When the injection depth is increased or the horizontal length of the injection pipe is increased, the outer pipe 20 is deformed by earth pressure. Therefore, it becomes difficult to insert and move the inner tube 21. However, by providing a synthetic rubber hose-like flexible joint 53 at a predetermined position of the inner tube 21 as shown in FIGS. 8A and 8B, the inner tube 21 can cope with the deformation of the outer tube 20. Then, the inside of the outer tube 20 can be turned. Further, the inner tube packer 27 is a rubber packer and contracts upon completion of injection at a predetermined stage. For this reason, the inner tube 21 can be easily transferred within the outer tube 21. Furthermore, since the conventional air packer is unnecessary, the diameter of the inner tube 21 can be reduced, and from this point, the outer tube can be adapted to deformation. In the present invention, the inner pipe may be formed of a hard pipe, but by forming the inner pipe with a hose on the near side from the range where the inner pipe discharge port exists, it is free with a lifting device with a scraper. It is possible to move in the outer tube.

  The inner tube packer 27 of the present invention is an impermeable bag body having elasticity, and synthetic rubber is usually used. When the internal pressure of the inner tube 21 does not act, this is formed into a cylindrical shape, preferably a cylindrical shape, and both ends are tightly connected to the inner tube 21 so that the discharge outlet 29 in the packer is located inside, and watertightness is maintained. Is done. For this reason, the inner tube 21 can be smoothly transferred into the outer tube 20. The inner tube packer 27 in FIGS. 2 to 10 shows a state in which the bag body is inflated by the inner tube inner pressure of the injected liquid and is in close contact with the inner wall of the outer tube 20.

  When the injection material used in the present invention is gelled in the inner tube packer 27, the packer will not function. Therefore, a material that has a long gelation time and is difficult to clog is desirable. Accordingly, it is preferable that the gelation time in the air is longer than the gelation time in the soil. Such an injection material does not cause gelation in the inner pipe flow path or the inner pipe packer even after the injection solution injected into the soil has gelled. The packer function can be continued by repeatedly contracting and expanding the packer until it is transferred to the injection stage and injected. As this type of injection material, the main material is non-alkaline water glass grout obtained by removing the alkali of water glass with an acid, or active silica obtained by dealkalizing water glass with an ion exchange resin or ion exchange membrane. Grout. These grouts have a gel time of 10 hours or more in the air, but retain a gel time of several hours in the soil. Therefore, these injection solutions enable a wide range of injections for a long time. Of course, when the injection time is short, an alkaline water glass grout having a gel time of 1 hour or longer can also be used.

  Of the above-mentioned injection materials, non-alkaline water glass grout and activated silica grout are solution-type, so that they do not have to worry about clogging in the inner tube packer 27. 27 hardly produces a silica gel. In addition, the ground requiring countermeasures against liquefaction often contains calcium such as shells and exhibits weak alkalinity. Therefore, the above-mentioned grout promotes gelation by raising the pH in the ground. For this reason, the gelation time in the above-ground part from the injection tube is longer than the gelation time in the ground. Therefore, there is no fear of gelation in the inner tube packer 27 of the injection tube while injecting into the ground. For this reason, injection is performed for a long time of several hours, or more than ten hours by installing an injection tube at a long distance of several tens of meters or several hundreds of meters under the injection conditions targeted by the present invention. Under the continuing injection conditions, in particular, non-alkaline water glass grout and activated silica grout make it possible to carry out the method of the present invention and can be said to be excellent injection materials in the present invention.

  Here, the basic principle of the packer function according to the present invention will be described with reference to FIG. FIG. 5 is an explanatory view of an experimental apparatus provided with an outer tube 20 and an inner tube 21 loosely inserted therein. The discharge valve 37 is closed and the outer tube 20, the inner tube 21, the inner tube packer 27, The relationship of the pressure with respect to the minimum unit of the device of the present invention comprising the outer pipe inner space 35 and the outer pipe discharge port 22 will be described.

First, the injection solution is sent from the inner tube flow path 31 of the inner tube 21 at the pressure P ₀ and the flow rate F ₀ . The pressure P ₀ is measured by a pressure gauge 38, and the flow rate F ₀ is measured by a flow meter 39. The inner tube 21 and the expandable inner tube packer 27 communicate with each other through the inner tube packer outlet 29, and the inner tube packer 27 expands. This internal pressure is the same as the pressure P _{0 of the} injected liquid.

On the other hand, a flow pressure adjusting device 40 is provided at the outer tube discharge port 22 of the outer tube 20. If the pressure regulating valve 41 of the device 40 is opened, the pressure P _{1 in the} outer pipe inner space 32 is naturally lower than P _{0 because the} space 32 is open to the outside. The pressure and flow rate at this time are measured by the pressure gauge 42 and the flow meter 43 of the flow rate pressure adjusting device 40. Accordingly, the inner tube packer 27 is expanded and formed as a packer as long as the feeding pressure of the injected solution is applied to the inner tube 21, and the injected solution discharged from the inner discharge port 30 flows outside through the outer tube inner space 32. It is discharged outside from the tube discharge port 22.

When the pressure regulating valve 41 is gradually closed to lower its opening degree, the pressure of the pressure gauge 42 increases (P ₁₁ ). At this time, if the liquid feeding flow rate F ₀ is the same, the inner pipe pressure P ₁ becomes higher than the pressure P ₀ . In this case, the pressure P ₁₁ is equivalent to the osmotic resistance pressure of the ground. However, as long as injection is performed in the ground, the pressure P ₁ is higher than the pressure P ₁₁ , and naturally, the pressure in the inner tube packer 27 becomes the pressure P ₁ and the pressure in the outer tube inner space 32. since it is maintained higher than the P ₁₁ so that the injection continues.

  However, the inner tube packer 27 is formed until the injected liquid in the inner tube 21 comes out from the inner tube discharge port 30 and is injected into the ground through the outer tube discharge 22. Since the outer tube inner space 32 is not sufficiently formed before, the injected liquid moves in the outer tube inner space 32 in the lateral direction, so that the injected solution moves in the outer tube and enters the ground from the unspecified outer tube discharge port 22. Since it is injected, it is not preferable because it is not injected into a predetermined injection region. For this reason, it is preferable that the inner tube packer 27 has already been formed at the time of discharge from the inner tube discharge port 30 to the outer tube inner space 32. For that purpose, it is preferable to be in a pressurized state when discharging from the inner tube 21. That is, it is desirable that an initial pressure is generated.

The initial pressure refers to the pressure inside the tube that is generated when the injected liquid is discharged from the discharge port in the air. Usually, the injection per stage, that is, one injection section between the upper and lower packers, although it depends on the section length, is usually 0.5m-4m, and the injection speed is 2-50 liters / minute, depending on the material of the inner tube packer against such infusion rate, typically the initial pressure 0.1 kgf / cm ² or more, preferably, 1 kgf / cm ² or more. In that case, the inner tube packer has already expanded when the injected liquid is discharged from the inner tube discharge port. Moreover, as for the liquid feeding pressure in FIG. 5, 1-50 kgf / cm < ² > is preferable.

As an initial pressure, depending on the material of the packer, 0.1 kgf / cm ² or more, usually if Shojire a 1 kgf / cm ² or more pipe pressure, packer comes into close contact with the outer tube wall. In this case, the diameter of the discharge port depends on the discharge speed per stage, but is preferably about 0.1 to 5 mm. Actually, the initial pressure can be arbitrarily set by appropriately designing one discharge port diameter, the number of discharge ports, and the elasticity of the inflatable packer corresponding to the injection speed per stage. Therefore, according to the present invention, the initial pressure can be easily formed by performing the following method, and the inner tube packer can be easily expanded faster than the discharge from the inner tube discharge port.

(A) The inner tube discharge port is made a fine hole.
(B) The area of the inner pipe discharge port is smaller than the cross-sectional area of the inner pipe flow path.
(C) The inner tube packer discharge port is made larger than the inner tube discharge port.
(D) The inner pipe discharge port is provided with a check valve. In FIG. 7D, the injection solution is discharged into the inner space of the outer tube only after the pressure of the injection solution in the inner tube becomes larger than the force of the spring 52.
(E) The inner tube discharge port is covered with a discharge resistor. In FIG. 7 (c), if the rubber sleeve 26 is used and the discharge port is covered, the injected liquid is discharged into the inner space of the outer pipe when the pressure of the injected liquid in the inner pipe corresponding to the elasticity of the rubber sleeve 26 increases. The
In the above, it is more preferable that the fine holes are injection holes as described above.

  Based on the above basic principle, the present invention has been completed as shown in the claims. In FIG. 5, reference numeral 44 denotes a depressurizing device, which includes a liquid feed valve 45, a three-way cock 46, and a water absorption pump 47. 48 is a drain pipe and includes a three-way cock 49.

  As can be seen from FIG. 5, the injection pressure is measured by a pressure gauge 38. Therefore, in order to know the injection pressure in the ground after being discharged from the inner pipe discharge port 30, it is only necessary to calculate by subtracting the discharge pressure in the air, but in order to know the actual pressure during the injection In the outer pipe inner space 32, either an electric earth pressure gauge, a strain gauge or a pore water pressure gauge is installed to calculate the liquid pressure of the injected liquid in the outer pipe inner space 32. Optimum injection can be performed by managing the injection speed, injection pressure, and injection tube operations such as injection interruption and completion based on the information collected in the management room. Of course, at the same time, either the same electric earth pressure gauge or the strain gauge pore water pressure gauge is provided in the inner tube packer 27, and by obtaining the information, fluctuations in the inner tube pressure and the external osmotic pressure, or the pressure difference By obtaining this information, it is possible to accurately grasp the condition of the discharge port of the inner tube and the condition of external gelation and feed back to the injection management.

  These measurement sensors can usually be installed in the outlet flow path of the inner pipe discharge port 30 in FIG. 7 (d) or FIG. 5, but a strain gauge or earth pressure gauge is also attached to the outer wall between the packers of the inner pipe. You can also. Of course, it can also be embedded in the wall surface inside the outer tube. The information is sent to the ground by wire or wirelessly through the inner tube or along a groove or the like provided in the outer tube. Moreover, in this invention, when inject | pouring for every stage which pinches | interposes two adjacent inner tube | pipe packers 27 and 27, the measured value of the flowmeter 39 of FIG. 5 will show the injection | pouring speed | velocity | rate in the stage as it is. On the other hand, as shown in FIGS. 4 and 6, when a constant injection flow rate is simultaneously injected into a plurality of injection stages, it is usually intended for the ground where the soil layer is stagnant in a plane. It can be considered that the discharge amount is distributed corresponding to the hole diameter of the tube discharge port. For this reason, the multistage simultaneous injection in the present invention is extremely useful as an injection method for preventing liquefaction that is injected in the horizontal direction. However, in the case of actual measurement, a sensor for measuring the flow velocity per minute is provided at the inner tube discharge port portion of each stage in FIG. 5 or FIG. By collecting in the management room, it is possible to grasp the injection speed and the injection amount of each stage in real time, and to feed back to the above-described injection operation for optimal injection management.

The flow rate measuring sensor is a constant flow valve or an integrated flow meter, and this may be provided in the flow path between the check valve and the inner pipe discharge port in FIG. In this case, the flow rate may be provided so as to fit in the inner space of the outer tube along the inner tube. In addition, the integrated flow meter may be taken out to the ground after the injection is completed, and the injection amount of the stage may be confirmed.
Information may be collected and recorded on the ground in real time. Further, as described above, the injection pressure sensor and the injection flow rate sensor are provided at the same time, so that the injection management can be performed by grasping the injection pressure and the discharge speed of the space in the outer tube at each injection stage.

  FIGS. 9A to 9G are explanatory views of a construction example for installing the injection tube in the ground, and FIG. 9A shows the vicinity of the head portion 58 of the boring rod 55. The head portion 58 of the boring rod 55 (single tube head) has a tip formed on a tapered surface 56 and is screwed by a screw body 59.

  As shown in FIG. 9B, the head portion 58 includes a transmitter that transmits position information in the ground 1, that is, a position information transmitter 60, and is connected to the tow bar 61. Information transmitted from the position information transmitter 60 is received by a receiving locator 62 installed on the ground surface 36 as shown in FIG.

  FIG. 9C is an explanatory view showing a state in which the boring rod 55 (single tube rod 55) is being dug into the ground 1 directly below the structure 54, and a drilling machine installed on the ground surface 36. The single tube rod 55 in which the position information transmitter 60 is built in is connected to the head portion 58 to the head portion 58 and digs into the ground 1 together with the injection of a boring fluid such as water while arbitrarily combining bending and horizontal. A reception locator 62 is installed on the ground surface 36, and the reception locator 62 receives radio waves of position information from the underground position information transmitter 60. The drilling machine 57 confirms the drilling direction and position of the boring rod 55 (single pipe rod 55) based on the information, and digs the single pipe rod 55 into the ground 1 while controlling it.

  Since the tip of the head portion 58 of the boring rod 55 is formed on the tapered surface 56, if the boring rod 55 is rotated, it goes straight, and if the rotation is stopped and press-fitted, it bends according to the direction of the taper. The rod 55 is dug in an arbitrary direction. The position of the head portion 58 can be grasped by a controller (not shown) and fed back to the boring operation. Further, by providing a gyro as a position information device at the tip of the boring rod 55, the position of the head portion 58 can be grasped through the boring rod 55.

  After excavating the single tube rod 55 to a predetermined position in the ground 1, as shown in FIG. 9D, the tow bar 61 is pulled to collect the position information transmitter 60 on the ground. As a result, the boring rod 55 is hollow from the tip to the end. Next, as shown in FIG. 9 (e), the outer tube 20 with the mechanical anchor 63 attached to the tip is inserted into the cavity of the boring rod 55 while the seal grout 25 is press-fitted.

  Next, when the single tube rod 55 is pulled out while pushing the outer tube 20, as shown in FIG. 9 (f), the mechanical anchor 63 is opened and bites into the drilling wall 24, whereby the outer tube 20 is anchored. And, it is fixed in the hole 23 by the seal grout 25.

  Further, after the seal grout 25 is solidified, as shown in FIG. 9 (g), a plurality of inflatable inner tube packers 27, 27,... The inner tube 21 having 30 is loosely inserted into the outer tube 20. Next, when the injection solution is press-fitted into the inner tube 21, the injection solution enters the packer through the discharge port 29 in the packer and expands the inner tube packers 27, 27,. A space 32 is formed. Further, the injected solution penetrates and injects into the ground through the inner tube outlet 30 and the outer tube outlet 22 while breaking the seal grout 25.

  After the injection, the inner pressure of the injected liquid in the inner tube 21 is released to contract the inner tube packer 27 and move the inner tube 21 to the next injection stage. This operation is repeated to permeate and consolidate the predetermined injection region. The outer tube 20 can be fixed by using an outer tube packer 33 as shown in FIG. 3 instead of the seal grout 25. The outer tube packer 33 is an inner tube having a double packer (not shown). Cement bentonite or the like is press-fitted into the outer tube packer 33 from the discharge port 34 in the outer tube packer and expanded to form the outer tube packer 33. 20 is fixed in the drilling hole.

  In the injection method of the present invention described above, an injection solution is injected from an injection solution pressurizing unit through a plurality of injection solution supply systems to an injection point in the ground, and a flow pressure detector is provided in the plurality of injection solution supply systems. The infusion liquid flow rate and / or pressure data detected from these detectors is transmitted to a central control device equipped with an infusion monitoring panel, and the infusion status from the infusion liquid feeding system is displayed on the screen of the infusion monitoring panel. While performing collective monitoring, performing injection from a plurality of selected injection points at the same time, and grasping the state of each injection, while performing the process from the start to the end of each injection line separately, And it is possible to perform the whole injection | pouring management, Therefore, the solidified body of a predetermined shape can be rapidly formed in a predetermined place.

  In the present invention, an electric earth pressure gauge (not shown) is installed in the outer pipe inner space 32 and the inner pipe packer 27 outside the inner pipe 21, and the injection pressure at the time of injection is measured in real time. It can also be a feedback to 130. In this case, the earth pressure gauge information is always collected on the ground part by wire and wirelessly and reflected in the injection control part.

  As described above, the injection method according to the present invention is suitable for liquefaction prevention injection under the structure 54 such as a building. For example, a plurality of layers can be laminated in the depth direction below the structure 54 and simultaneously injected, or a plurality of injection tubes can be set in parallel in the horizontal direction below the structure 54 and simultaneously injected. Alternatively, a plurality of layers can be formed simultaneously in the depth direction and the horizontal direction. In the present invention, the boring for installing the injection pipe may be performed from the ground surface near the structure, and horizontally into the foundation ground of the structure with a boring rod incorporating an information transmitter from the vertical pile to the tip. You may go.

  The above-described method of the present invention simplifies the structure by reducing the pipe diameter, thereby reducing the drilling hole and improving the workability to obtain economic efficiency. Further, the oil tank foundation ground, under the runway of the airfield, It enables long section injection of building foundation ground, reservoir bottom, industrial waste bottom, etc., and ensures the injection effect.

  That is, the construction method of the present invention can reduce the injection tube diameter with a simple structure, and can insert and inject a long injection tube directly under the structure in the horizontal direction or while bending. In particular, drilling holes of arbitrary shape, that is, boring holes, are drilled in the ground to be improved, and the injection solution is simultaneously injected into the ground from the boring holes through a plurality of discharge ports to improve the ground. In addition, it enables rapid penetration and consolidation in a predetermined penetration and solidification form at a predetermined position, and the ground improvement under the existing structure that is difficult to inject ground is rapidly and reliably applied to further improve the ground. It is an industrially useful invention.

It is a basic view of an example of ground injection below the structure. It is sectional drawing of one specific example of the apparatus used for this invention construction method. It is sectional drawing of the other specific example of the ground injection apparatus concerning this invention. It is sectional drawing of the other specific example of the ground injection apparatus concerning this invention. It is explanatory drawing of the experimental apparatus for demonstrating the principle of the packer function of this invention. It is explanatory drawing of the apparatus provided with multiple inner tubes. It is explanatory drawing showing the discharge port in an inner tube packer, and an inner tube discharge port, Comprising: The relationship of a magnitude | size is represented. It is explanatory drawing showing the discharge port in an inner tube packer, and an inner tube discharge port, Comprising: The relationship of a magnitude | size is represented. It is explanatory drawing of the rubber sleeve and check valve which are covered with an inner pipe discharge port. It is explanatory drawing of the rubber sleeve and check valve which are covered with an inner pipe discharge port. It is explanatory drawing of the state which connected the inner pipe | tube with the flexible joint, Comprising: One inner pipe | tube is represented. It is explanatory drawing of the state which connected the inner pipe | tube with the flexible joint, Comprising: Two inner pipes are represented. It is a top view of the boring rod used for this invention. It is sectional drawing of the head part of the boring rod used for this invention. It is explanatory drawing showing the state which is excavating the boring rod directly under a structure. It is sectional drawing of the state which is pulling the tow bar and collect | recovering the transmission locator on the ground. It is sectional drawing of the state which has inserted the outer tube | pipe into the cavity in a boring rod. It is sectional drawing of the state which fixed the outer pipe | tube in the drilling hole. Sectional drawing of the state which inserted the inner pipe | tube in the outer pipe | tube, expanded the inner pipe | tube packer, and was fixed in the outer pipe | tube is represented. It is sectional drawing of the conventional apparatus, Comprising: Process drawing is represented. It is sectional drawing of the conventional apparatus, Comprising: Process drawing is represented. It is sectional drawing of the conventional apparatus, Comprising: Process drawing is represented. It is sectional drawing of the conventional apparatus, Comprising: Process drawing is represented.

Explanation of symbols

A Ground injection tube 1 Ground 20 Outer tube 21 Inner tube 22 Outer tube discharge port 23 Drilling hole 24 Drilling wall 25 Seal grout 26 Rubber sleeve 27 Inner tube packer 28 Fastener 29 Inner tube packer discharge port 30 Inner tube discharge port 31 Inner pipe flow path 32 Outer pipe inner space 33 Outer pipe packer 34 Outer pipe packer discharge port 35 Outer pipe outer space 54 Structure 55 Boring rod 60 Position information transmitter 130 Controller 135 Injection liquid tank 136 Pump

Claims (11)

In the ground injection method in which the injection pipe is bent in the ground or installed horizontally, or in any combination of bending and horizontal, and the injection liquid is injected into the ground through the injection pipe, the injection pipe has different axial directions. An outer tube having a plurality of outer tube outlets at a position, and a plurality of inflatable inner tube packers made of elastic and impermeable bag bodies, which are loosely inserted into the outer tube, so as to sandwich the outer tube outlets And an inner tube having a discharge port in the packer in the inner tube packer, and an inner tube having an inner tube discharge port between the inner tube packers provided at the interval. It is a pipe and is installed in a drilling hole drilled by a boring rod with a built-in position information transmitter at the tip, so that the inner pipe discharge port satisfies any of the following (a) to (c) Formed, inflatable inner tube packer expands inner tube packer Without supplying a packer fluid conduit to cause the infusible inner tube packer to expand due to the liquid feed pressure of the infusible inner tube packer. A space is formed between the outer pipe and the injection liquid is discharged from the inner pipe discharge port into the outer pipe inner space, and the injection liquid is injected from the outer pipe inner space into the ground through the outer pipe discharge port. Or the inner tube packer is contracted by reducing the pressure in the inner tube by draining a part of the infusion solution in the inner tube to make the inner tube movable within the outer tube. A ground injection method characterized by repeating injection in the same manner at the position.
(A) An inner tube discharge port is formed in a pore.
(B) The inner tube discharge port is formed in a smaller pore than the inner tube packer discharge port.
(C) The area of the inner pipe discharge port is formed smaller than the cross-sectional area of the inner pipe flow path. The ground injection construction method according to claim 1, wherein the installation of the injection pipe in the drilling hole is performed as follows (1) to (3).
(1) A single-tube boring grod with a position information transmitter at the tip and a head connected to the tow bar is used to dig into the ground while checking the drilling direction and position.
(2) After excavating the single tube boring rod to a predetermined position in the ground, pull the tow bar and collect the position information transmitter on the ground.
(3) Insert the outer tube fitted with the tip mechanical anchor into the cavity of the single tube boring rod, pull out the injection rod, and fix the outer tube in the drilling hole with the mechanical anchor.   2. The outer tube packer according to claim 1, wherein a plurality of outer tube packers are installed so that the outer tube discharge port is sandwiched between the outer tubes, and the outer tube packer is filled with a caking agent and expanded to be fixed and installed on the ground. The ground injection method described in 1.   4. The outer tube packer according to claim 3, wherein the outer tube packer is a water-permeable bag, and the outer tube packer is filled with a caking material and expanded to a diameter larger than the drilling hole diameter to form a packer in the soil. 4. The ground injection method according to claim 3, wherein the ground is fixed and installed on the ground. In Claim 1, the inner pipe is provided with three or more inflatable inner pipe packers to form a plurality of outer pipe inner spaces, whereby the injection liquid is simultaneously injected into the ground from the plurality of outer pipe discharge ports. The ground injection construction method according to claim 1.   The ground injection method according to claim 1, wherein a plurality of inner pipe flow paths are provided, and each inner pipe outlet is opened to a different inner space of the outer pipe.   2. The inflatable inner tube packer according to claim 1, which is an elastic and impermeable bag, expands until it comes into close contact with the inner wall of the outer tube by the internal pressure of the infusion solution, and stops the infusion solution delivery. The ground injection method according to claim 1, wherein the ground pipe is contracted by draining a part of the injected liquid in the inner pipe and reducing the pressure in the inner pipe, thereby making the inner pipe movable in the outer pipe. .   The elastic impermeable bag body according to claim 7, wherein the elastic impermeable bag body is a cylindrical body, and both ends thereof are tightly attached to the inner pipe so that the discharge outlet in the packer is located in the cylindrical shape. Ground injection method.   The ground injection method according to claim 1, wherein the inner pipe flow path is provided with a depressurization device.   2. The injection pressure at the time of injection according to claim 1, wherein any one of an electric earth pressure gauge, a strain gauge or a pore water pressure gauge is installed in the outer pipe inner space and / or the inner pipe packer. Ground injection method.   The ground injection method according to claim 1, wherein a flow rate measuring sensor is provided at the inner tube discharge port to measure an injection speed and an injection amount at the time of injection.

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