KR102464905B1 - Method of Ground Reinforcement using silica sol - Google Patents

Abstract

The present invention relates to a ground reinforcement method for improving ground such as soft ground using silica sol. Specifically, the ground reinforcement method comprises: a ground drilling step (S100) of performing drilling on the ground with a drilling device; a ground reinforcing material injection step (S200) of preparing a first liquid containing silica sol and a second liquid containing cement, an expanding agent, and water and simultaneously injecting the liquids into the drilled hole; and a ground hardening step (S300) of hardening the ground by mixing and solidifying the injected ground reinforcing material in the drilled hole.

Description

{Method of Ground Reinforcement using silica sol}

The present invention relates to a ground reinforcement method for improving the ground such as soft ground using silica sol.

Patent Invention 001 to Patent Invention 004 suggest prior inventions in the related art to which the present invention is reached.

Patent Document 001 discloses that the upper injection part and the lower injection part of the triple pipe rod or the quadruple pipe rod of the grout material injection device are installed at a predetermined interval, and ultra-high pressure water is sprayed from the top injection part to cut the composition area and at the same time cut the cut soil. By discharging to the ground, and at the time when the lower spraying part is raised to the depth started by the upper spraying part, the grout material and hardener are sprayed and stirred in the lower spraying part to improve the cut composition area and at the same time to rapidly solidify the grout material with a hardener, Make sure that no solidification material is mixed with the soil discharged from the upper spraying part, and the discharged slime is separated into water and soil with a separator to reuse the separated water, and the slime reduces the amount of slime by removing moisture, An object of the present invention is to provide a high-pressure spraying ground improvement system and method using a hardener manufacturing device and a slime reprocessing device that enables general residual soil treatment that does not require waste treatment.

Patent Document 002 discloses that, during ground improvement and reinforcement work in offshore areas, a hardening agent such as cement paste (Portland cement) or mortar (Portland cement + sand + water) is pumped through the injection hole of the tip device at ultra-high pressure to transport the hardener to the target ground. Blast furnace, which is an industrial by-product that is hydrated by the alkaline component of seawater, using seawater that can be easily obtained from the sea without using or using only a portion of Portland cement, which is harmful to the sea First dilute slag, mix sand and lime, a natural material, with blast furnace slag to increase the strength of marine tidal flats and secure economic feasibility. After rotating the ultra-high pressure water and compressed air from the ultra-high pressure water nozzle, the compressed air nozzle and the hardener nozzle installed in the tip device to loosen the target ground, the hardener is pumped through the hardener nozzle into the loose ground to remove the local soil. An object of the present invention is to provide a hardening agent for improving soft ground, an ultra-high pressure water spraying device thereof, and a ground improvement method using the same, in which the hardener injected while pushing is filled to form a soft ground structure by solidification of the hardener.

Patent Document 003 discloses that the grouting composition includes a sodium silicate compound composed of (a) 16 to 26.5% by weight of SiO2, (b) 3 to 7% by weight of Na2O, and (c) 66.5 to 81% by weight of water. In addition, the grouting method of the present invention comprises (a) a first slurry composed of cement for quick setting and water, and a sodium silicate compound composed of 16 to 26.5% by weight of SiO2, 3 to 7% by weight of Na2O, and 66.5 to 81% by weight of water. The first injection step of injecting the quick-setting grouting material mixed with the 2 slurry into the ground, and (b) the third slurry composed of cement and water for completion in the injected quick-setting grouting material, and 16 to 26.5 wt% of SiO2, 3 to It consists of a secondary injection step of injecting a grouting material for completion in which a fourth slurry composed of a sodium silicate compound consisting of 7% by weight of Na2O and 66.5 to 81% by weight of water is mixed.

Patent Document 004 relates to a grout for waterproofing and reinforcing the ground for soft ground, and more specifically, a high-functional injection material in which inorganic alumina powder, a vegetable foaming agent, and an acrylic polymer are mixed, and a grout material including the high-functional injection material And, by proposing a mixed production of the grout material and an injection device for injecting it into the ground, a grout material including the high-functional injection material, and a grout method using the injection device, the grouting construction performance and durability are improved and environmental pollution It is very eco-friendly by minimizing the amount of existing materials that cause Because it is mixed and injected in the field, it has excellent usability in the field, and it has excellent speed-diameter performance regardless of seasonal temperature changes, so that uniform construction performance can be obtained. it has an effect.

US 10-0886220 B1 (registration date February 23, 2009) US 10-0884285 B1 (registration date February 11, 2009) US 10-1078044 B1 (registration date October 24, 2011) US 10-1619218 B1 (registration date May 02, 2016)

The present invention relates to a ground reinforcement method for improving the ground such as soft ground using silica sol.

The present invention is an invention for a ground reinforcement method, and specifically, in the ground reinforcement method, a ground drilling step (S100) of performing a hole in the ground with a drilling device; and a ground reinforcement material injection step (S200) of preparing a first liquid containing silica sol and a second liquid containing cement, an expanding agent, and water, respectively, and injecting them into the drilling hole at the same time; and a ground hardening step (S300) of hardening the ground as the injected ground reinforcing material is mixed and solidified in the drilling hole.

The present invention relates to a ground reinforcement method, and in the invention presented above, in the ground reinforcement material injection step, a first mixing step (S210) of mixing an expanding agent and water with the cement, which is the second liquid, on the ground; and the first and a second mixing step (S220) in which the liquid and the second liquid are simultaneously injected into the ground and mixed in the ground.

The present invention relates to a ground reinforcement method, and in the invention presented above, the second liquid is 35 to 65 parts by weight of cement and 35 to 65 parts by weight of an expanding agent with respect to 100 parts by weight of the first liquid in the ground reinforcement injection step. and 85 to 115 parts by weight of water.

The present invention relates to a ground reinforcement method, and in the invention presented above, in the ground reinforcement material injection step, a first liquid injection pump for injecting a first liquid; and a second liquid injection pump for injecting a second liquid; and a first injection pipe extending from the first and second liquid injection pumps into the perforated hole, respectively; and a second injection pipe.

The present invention is an invention for a ground reinforcement method, and in the invention presented above, a hole cap is formed at the inlet of the drilling hole.

The present invention is an invention for a ground reinforcement method, and in the invention presented above, the outlet of the first injection pipe and the second injection pipe has a discharge part having a diameter smaller than the inner diameter of the first injection pipe and the second injection pipe; including those formed.

The present invention is an invention for a ground reinforcement method, and in the invention presented above, the step of drilling a hole in the ground by a forward rotation of the drilling device in the ground drilling step (S110); and discharging soil (S120); and removing the drilling device from the ground by reverse rotation (S130).

The present invention relates to a ground reinforcement method for improving the ground, such as soft ground, using silica sol. When silica sol is used as an injection material, the injection effect continues semi-permanently. In addition, it has the advantage of reducing environmental pollution such as groundwater contamination due to material leaching.

1 and 2 are a flow chart of the ground reinforcement method of the present invention.
Figure 3 is a cross-sectional view showing the ground drilling step of the present invention.
4 and 5 are cross-sectional views showing the step of injecting the ground reinforcement into the perforation hole of the present invention.
6 is a cross-sectional view showing a state in which the ground reinforcement is hardened in the perforated hole of the present invention.

Hereinafter, the most preferred embodiment of the present invention will be described in detail in order to be described in detail enough to be easily practiced by those of ordinary skill in the art to which the present invention pertains.

The numbers cited in the examples below are not limited only to the objects of reference, and may be applied to all examples. An object that exhibits the same purpose and effect as the configuration presented in the embodiment corresponds to an equivalent replacement object. The higher-level concept presented in the examples includes sub-concept objects that are not described.

[Example 1-1] The present invention is an invention for a ground reinforcement method, and specifically, in the ground reinforcement method, a ground drilling step (S100) of performing a hole in the ground (G) with a drilling device (D); and a ground reinforcement material injection step (S200) of preparing a first liquid 100 containing silica sol, a second liquid containing cement, an expanding agent, and water, respectively, and injecting them into the drilling hole at the same time (S200); and a ground hardening step (S300) of hardening the ground as the injected ground reinforcing material is mixed and solidified in the drilling hole.

The present invention (Example 1-1) aims to improve the ground such as soft ground using silica sol.

The existing water glass-based chemical liquid injection method, which was constructed as an improved method for stabilizing the conventional soft ground, was mainly carried out by mixing the injection material in the field. However, in the case of incorrect on-site mixing, leaching of alkali components from the injection fixing agent proceeds by free water and adsorbed water over time after injection, and eventually most of the injection material is lost/disappeared, resulting in poor durability and poor durability. As a result, there is a possibility of contaminating groundwater, raising questions about the reliability of safety and environmental pollution.

Therefore, as an alternative to this, it has been required to develop a new reinforcing material with excellent durability and less possibility of environmental pollution and its injection method. There is a drug injection method.

Silica sol is a silicate-based material such as sodium silicate or calcium silicate reacts with a specific inorganic acid or organic acid to neutralize the alkali component contained in the component. / Refers to the removed acidic to neutral colloidal silica solution. This silica sol solution is completely gelled/condensed in a neutral region (pH: 6 to 8) by an alkaline curing agent to produce a neutral solid that is neither acidic nor alkaline, and the original silica sol solution already has a certain molecular weight. Because of this increased polymer state, the structure of the condensed material becomes a stronger polymeric linkage structure when it is subsequently condensed by a curing agent, unlike the case of curing of a general water glass solution. Therefore, there is almost no leaching of alkali, and it can be a non-polluting solid that is not diluted or lost even in a large amount of running water during curing or after consolidation.

Therefore, when silica sol is used as an injection material, the injection effect is maintained semi-permanently, showing high reliability compared to other methods, and has the advantage of reducing environmental pollution such as groundwater contamination by leaching of alkali components.

In the present invention, there are technical characteristics in the stage of the ground reinforcement method using silica sol, and it is intended to secure the reliability of the improved ground performance by forming bulbs with an effective ground drilling method and an injection method of a ground reinforcement material compared to the prior art.

In order to implement this, a ground drilling step of drilling the ground to be improved with a drilling device; and preparing a first liquid containing silica sol and a second liquid containing cement inside the drilled hole, respectively, into the drilling hole Simultaneous injection of ground reinforcement material; and a ground hardening step in which the injected ground reinforcing material is mixed and condensed (quickly set) in the drilling hole to harden the ground.

[Example 2-1] The present invention is an invention for a ground reinforcement method, and in Example 1-1, in the ground reinforcement material injection step, a first mixing step of mixing an expanding agent and water with the cement, which is the second liquid, on the ground (S210); and a second mixing step (S220) in which the first liquid 100 and the second liquid are simultaneously injected into the ground (G) and mixed in the ground (S220).

[Example 2-2] The present invention is an invention for a ground reinforcement method, and in Example 2-1, in the ground reinforcement material injection step, the second liquid is 35 to 65 weight of cement with respect to 100 parts by weight of the first liquid It consists of 35 to 65 parts by weight of part and swelling agent and 85 to 115 parts by weight of water.

[Example 2-3] The present invention is an invention for a ground reinforcement method, and in Example 2-2, the expanding agent is bentonite; and fly ash; Including one or more selected from.

[Example 2-4] The present invention is an invention for a ground reinforcement method, and in Example 2-3, anhydrite is further added to the expanding agent.

[Example 2-5] The present invention relates to a ground reinforcement method, and in Example 2-1, a curing retardant is further added to the second liquid.

[Example 2-6] The present invention is an invention for a ground reinforcement method, and in Example 2-1, a curing accelerator is further added to the second liquid.

[Example 2-7] The present invention is an invention for a ground reinforcement method, and in Example 2-2, graphene oxide is further added to the second liquid.

The present invention (Examples 2-1 to 2-7) specifies the characteristics of the ground reinforcement material injection step and the injected material. The ground reinforcing material injection step is a process for preparing a first liquid containing silica sol and a second liquid containing cement, and a first mixing step of mixing cement, an expanding agent, and water on the ground to prepare the second liquid can be configured. This is mixed to inject cement as a grouting material into the perforation hole, and may basically include cement, an expanding agent, and water. Thereafter, a second mixing step of injecting the second liquid formed in the first mixing step into the perforation hole at the same time as the first liquid to be mixed with each other in the ground is configured. The second liquid is a cement mixture and is applied to form bulbs having strength inside the drilling hole. Before mixing with the first liquid, silica sol, inside the drilling hole, an additive is added from the outside according to the field conditions. can increase

For this purpose, cement can be used as a grout material, usually portland cement or a mixture of ordinary portland cement and blast furnace slag cement. In the case of cement, the volume of the bulb may decrease in the perforated hole due to the property of shrinking during the hydration process to express strength. The expanding agent may use bentonite, fly ash, anhydrite, etc., and in the case of fly ash, coal-fired fly ash having a silicon dioxide (SiO 2 ) content of 30 wt % or more is preferable. 35 to 65 parts by weight of the bentonite and the fly ash are preferably mixed with respect to 35 to 65 parts by weight of the cement, and bentonite-fly ash can also be used as a mixture. When the ratio of the expanding agent is less than the above range relative to the weight of cement, the expandability is lowered, and the shrinkage phenomenon is large when the ground reinforcement injected into the drilling hole is solidified, so the effect as a solidifying material for grouting for the ground may be reduced, and long-term expansion when mixed with There is a possibility that hardness may become low.

In addition, anhydrite is a by-product generated during the manufacture of phosphoric acid, and when the anhydrite is used in cement, shrinkage of the hardened cement can be prevented and the strength of the cement mixture can be increased. The anhydrite is a fast-hardening expanding agent, and it is preferable to use it for additional mixing in the composition of bentonite and fly ash expanders according to field conditions such as ground type.

The curing retardant is selectively applied to delay the setting time by applying to the site affected by temperature conditions such as hot weather in summer. Citric anhydride and sodium borate can be used. The curing time can be delayed.

The hardening accelerator is selectively applied to reduce the leaching phenomenon of the ground reinforcing material injected during the improvement of sandy soil such as sand, and specifically aluminum sulfate may be used. When a small amount of aluminum sulfate is added, coagulation and other properties are not affected, but curing is accelerated by accelerating the hydration reaction and strength is increased.

In addition, in the present invention, graphene oxide may be added into the mixture of the two liquids in order to improve the performance of the second liquid. The graphene oxide is used to improve durability by enhancing the strength after curing of the mortar by bonding with other components mixed in the mortar composition. The graphene oxide is preferably used in an amount of 0.2 to 6 parts by weight, preferably 0.4 to 2.4 parts by weight, based on the total weight of the second liquid for strengthening the watertightness and durability of the mortar composition. When graphene oxide is incorporated in an amount of 0.4 parts by weight or more, the micropores of the ground reinforcing material become tight, and it is effective in reducing the occurrence of cracks in the formed bulbs. In addition, the compressive strength and flexural strength are also increased, thereby increasing durability, thereby increasing wear resistance. When the graphene oxide is incorporated in excess of 6 parts by weight, the fluidity is reduced and it is difficult to secure the reliability of the mixing of the first and second liquids in the ground when the second liquid is injected.

[Embodiment 3-1] The present invention relates to a ground reinforcement method, and in Example 1-1, a first liquid injection pump 110 for injecting a first liquid 100 in the ground reinforcement material injection step; and a second liquid injection pump 210 for injecting a second liquid; and a first injection pipe 120 extending from the first and second liquid injection pumps into the perforated hole, respectively; and a second injection pipe 220 .

[Embodiment 3-2] The present invention is an invention for a ground reinforcement method, and in Embodiment 3-1, a hole cap 300 is formed at the inlet of the drilling hole.

[Embodiment 3-3] The present invention is an invention for a ground reinforcement method, and in Example 3-1, the hole cap 300 is an insertion part 310 inserted into the drilling hole; and enlarged formation at the top of the drilling hole and a pressing unit 320 for pressing the hole inlet.

The present invention (Examples 3-1 to 3-3) specifies technical features for improving the injection effect of the ground reinforcement material in the ground reinforcement material injection step. Specifically, a first liquid injection pump and a second liquid injection pump for injecting the first and second liquids are respectively provided outside the ground and near the drilling hole, and extend from the first and second liquid injection pumps into the drilling hole. It may include first and second injection pipes for injecting the first and second liquids. The first and second injection pipes can be used as flexible high-pressure pipes in a certain section or all sections in order to facilitate entry and withdrawal into and out of the perforated hole, and to facilitate removal of residual material in the pipe after construction.

In an embodiment, a hole cap may be formed at the inlet of the perforation hole into which the first and second liquids are injected. The hole cap is positioned at the entrance of the perforated ground, and by seating the hole cap, it minimizes the penetration of foreign substances into the perforated hole after excavating the perforated hole and before injecting the ground reinforcing material, and injecting and mixing the first and second liquids. This is to minimize contamination of the surrounding ground when dissolution of

The hole cap may be formed of an insertion unit inserted into the perforation hole; and a pressing unit formed enlarged at the upper portion of the perforation hole to press the entrance of the perforation hole. This is to prevent separation of the hole cap by placing an insertion part inserted at a certain depth from the entrance of the drilling hole in the hole cap, and at the same time press the ground around the hole with the pressurizing part. And it is possible to reduce the phenomenon that the second liquid is leached before mixing. To this end, the pressing part may be manufactured as a heavy object by using an iron plate, etc., and the hole cap may be managed in a state in which the insertion part and the pressing part are separated for ease of management such as transportation, and may be integrated through assembly in the field.

[Example 4-1] The present invention is an invention for a ground reinforcement method, and in Example 3-1, at the outlets of the first injection pipe 120 and the second injection pipe 220, the first injection pipe and The discharge portion 400 having a smaller diameter than the inner diameter of the second injection pipe; includes a formed one.

[Example 4-2] The present invention is an invention for a ground reinforcement method, and in Example 4-1, a blade of a spiral that crosses the inner diameter of the discharge unit is formed in the discharge unit 400 .

[Example 4-3] The present invention relates to a ground reinforcement method, and in Example 4-1, a spiral trajectory is formed on the inner wall surface of the discharge unit 400 .

The present invention (Examples 4-1 to 4-3) specifies technical features to improve the discharge performance of the first and second injection pipes. The first and second injection pipes are for injecting the first liquid and the second liquid into the perforation hole, respectively, and the injection speed is affected by the first and second pressure pumps and the characteristics of the material when injected. To this end, a discharge portion may be separately formed at the outlets of the first and second injection pipes. The discharge part may be formed to be smaller than the inner diameter of the first and second injection pipes to improve the ejection speed of the first and second liquids ejected according to the pressure of the first and second pressure pumps. In addition, a spiral blade crossing the inner diameter of the discharge unit may be attached to the discharge unit, or a spiral trajectory may be formed on the inner wall surface of the discharge port in the axial direction of the pipe. This is to cause the first and second liquids to be ejected to be ejected by causing a tornado along the spiral structure. This is to ensure that the ejected second liquid is mixed as much as possible in a short time within the perforation hole.

[Example 5-1] The present invention is an invention for a ground reinforcement method, and in Example 1-1, in the ground drilling step, drilling a hole in the ground by forward rotation of the drilling device (D) (S110) ; and discharging soil (S120); and removing the drilling device from the ground by reverse rotation (S130).

[Example 5-2] The present invention is an invention for a ground reinforcement method, and in Example 5-1, in the step of removing from the ground by rotating the drilling device (D) in reverse, forming a scratch on the wall surface of the hole Step (S131); includes.

[Example 5-3] The present invention is an invention for a ground reinforcement method, and in Example 5-2, in the step of forming a scratch on the wall surface of the drilling hole, the blade of the drilling device when the drilling device (D) rotates in reverse. The formed ratchet; includes a protruding one.

[Example 5-4] The present invention is an invention for a ground reinforcement method, and in Example 5-3, the ratchet is hinged to the blade; including combined.

The present invention (Examples 5-1 to 5-4) specifies technical features for improving the effect that the ground reinforcement is injected into the ground in the ground drilling step. In one embodiment, the drilling device includes a step of drilling a hole in the ground through a forward rotation for excavation and discharging soil at the same time. It may include the step of easily removing from the ground by rotating the drilling device in reverse. In case of reverse rotation to remove the drilling device, scratches may be additionally formed on the wall of the drilling hole, which is a physical method to form scratches on the wall of the drilling hole pressurized according to the excavation, thereby dispersing the high-density soil into the drilling hole in the future. The ground hardener mixed in the surface can penetrate into the scratch wall to form more expanded bulbs, thereby increasing the ground reinforcing effect. To this end, by forming a ratchet that protrudes only during reverse rotation on the blade of the punching device, it may be formed so that the projection also protrudes only during reverse rotation. The ratchet may be formed in a plurality of spaced apart from the outer surface of the blade, and is basically hinged to the blade to enable rotation. In addition, the ratchet is equipped with a trigger that protrudes in one direction so that the perforator can protrude only when the perforator rotates in the ground reversely, and after being drawn out of the ground, it can be coupled with an elastic material such as a spring so that it can be coupled to the blade again. can

G : Ground D : Drilling device
100: first liquid 110: first liquid injection pump
120: first liquid injection pipe
200: second liquid 210: second liquid injection pump
220: second liquid injection pipe
300: hole cap 310: insertion part
320: pressurized part
400: discharge part

Claims (7)

In the ground reinforcement method,
Ground drilling step (S100) of performing a drilling in the ground with a drilling device (D); and
A ground reinforcement material injection step (S200) of preparing each of the first liquid 100 including silica sol and the second liquid 200 including cement, expanding agent, water and graphene oxide and injecting it into the drilling hole at the same time (S200); and
A ground hardening step (S300) of hardening the ground as the injected ground reinforcing material is mixed and solidified in the perforation hole;
In the ground drilling step (S100), the step of drilling a hole in the ground by forward rotation of the drilling device (S110); and
discharging soil (S120); and
Including; removing from the ground by rotating the drilling device in reverse (S130);
In the step (S130) of rotating the drilling device (D) in reverse to remove it from the ground, forming a scratch on the wall surface of the hole (S131); includes;
In the ground reinforcement injection step, the first liquid injection pump 110 for injecting the first liquid 100; and the second liquid injection pump 210 for injecting the second liquid 200; and
a first injection pipe 120 extending from the first and second liquid injection pumps 110 and 120 to the inside of the perforation hole, respectively; and a second injection pipe 220;
A discharge portion 400 having a smaller diameter than the inner diameter of the first injection pipe 120 and the second injection pipe 220 is formed at the outlet of the first injection pipe 120 and the second injection pipe 220; ,
The discharge unit 400 has a blade of a spiral that crosses the discharge unit inner diameter; is formed,
A spiral trajectory is formed on the inner wall surface of the discharge unit 400,
In the step (S131) of forming a scratch on the wall surface of the drilling hole, the ratchet formed on the blade of the drilling device when the drilling device (D) rotates in reverse; includes protruding,
The ratchet comprises a hinge-coupled to the blade,
In the ground reinforcement injection step (S200), a first mixing step (S210) of mixing an expanding agent, water, and graphene oxide with the cement as the second liquid on the ground (S210); and
A second mixing step (S220) in which the first liquid and the second liquid are simultaneously injected into the ground and mixed in the ground (S220);
In the ground reinforcing material injection step (S200), the second solution is 35 to 65 parts by weight of cement, 35 to 65 parts by weight of an expanding agent, 85 to 115 parts by weight of water, and 0.2 to 6 parts by weight of graphene oxide with respect to 100 parts by weight of the first solution. includes wealth,
Including that a hole cap 300 is formed at the inlet of the perforation hole,
The hole cap 300 has an insertion part 310 inserted into the perforated hole; and
A ground reinforcement method comprising a; a pressing part 320 that is enlarged and formed in the upper part of the drilling hole to press the inlet of the drilling hole.
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