JP2822899B2 - Ground injection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground injection method,
In particular, a ground injection method for improving the stagnant ground by injecting the injection material into the stagnant ground through which inflow water and groundwater from rivers and the like pass, clogging the gap between the sediment particles and stopping the water. The present invention also relates to a ground injection method for injecting an injecting material into a void formed around an underground structure or a crack such as a crack or a crack in a rock to fill or stop water.

[0002]

2. Description of the Related Art In order to improve a stagnant ground through which inflow water and groundwater from rivers and the like pass, as an injection material used for clogging gaps between sediment particles constituting the ground to stop water. More generally, a cement-based solidifying material such as cement milk or a chemical-based solidifying material such as a water glass solution is used. According to this ground injection method, the injection material made of the solidified material is filled in the gaps between the sediment particles such as gravel and gravel constituting the water-impregnated ground, and is solidified after a lapse of a predetermined time to fill the gap between the sediment particles. It can block the passing water and thereby perform the function of stopping water and the function of reinforcing the ground.

On the other hand, due to scouring of seawater, river water, groundwater, or the like, or subsidence in the surrounding ground, water has been generated on the back of structures such as revetment structures and river embankments, and around troughs and various buried pipes. For voids or cracks and cracks in rock, joints and cracks in underground structures, cement-based solidified materials such as cement milk to prevent the expansion of such voids or to stop water A solidification material of a chemical solution such as a water glass solution is injected.

[0004]

However, according to the above-mentioned conventional ground injection method, when the flow rate of groundwater or inflow water is large, or when the ground to be ground-improved has a large grain size, When the gap between the sediment particles is large, the flowing water passing between the soil particles in the stagnant ground causes the injected material to be diluted or washed away and the solidified component to be reduced, so that a sufficient water stopping effect can be obtained. There was a problem that it disappeared.

[0005] As means for effectively stopping water in a stagnant ground with a large flow rate, an injection material as a fluid is used.
For example, a method has been considered in which a solid component such as a fiber is mixed, and the injected material is retained by a cross-linking structure formed in the gap between the earth and sand particles by the solid component, thereby preventing dilution and loss of the injected material. According to the above, since the solid component which is a foreign substance is mixed in the injection material as a fluid, the gap is small especially in a water-impregnated ground where the particle size of the earth and sand particles is relatively small, so that the injection is performed in a predetermined range. Before the material spreads sufficiently, the gaps between the sediment particles are clogged and closed, and there is a problem that it is difficult to uniformly stop the water in the water-retaining ground over a wide range.

[0006] On the other hand, according to the submerged ground filling method in which a gap is filled with an injection material or water is stopped in the gap, the injected injection material is invaded by seawater, river water, groundwater, or the like that intrudes from a gap in the structure. There is a problem that it is washed away or lost in the surrounding ground and it is not possible to efficiently fill or stop the water, and the injected material enters the structure from the gap of the underground structure such as the trough, There is a problem that the function of the facility such as the cable disposed inside the structure may be impaired.

Accordingly, the present invention has been made in view of such a conventional problem, and an injection material including a solidified material is sufficiently supplied to a stagnant ground in a range in which water is stopped to improve the ground. It is another object of the present invention to provide a ground injection method capable of easily obtaining a desired water stopping effect and a ground reinforcing effect by uniformly dispersing.

[0008] Further, the present invention fills or efficiently fills the gap portion by sufficiently and uniformly spreading the injectable material including the solidifying material while closing the gap between the ground and the structure around the gap portion. It is an object of the present invention to provide a ground injection method capable of stopping water.

[0009]

Means for Solving the Problems The present invention has been made to achieve the above object, and the gist of the invention is to inject an injectable material into a stagnant ground through which inflow water or groundwater from a river or the like passes, In the ground injection method for improving the water-stowed ground by clogging the gap between the sediment particles and stopping the water, the injection material may be a cement-based solidified material such as cement milk or a chemical such as a water glass solution. The ground injection method is characterized by using a ground improvement material obtained by mixing a short fiber which contains water and causes at least surface slimming to a chemical liquid solidifying material.

Another aspect of the present invention relates to a void formed around an underground structure or in an earth structure, a crack formed in a rock or an underground structure, a void such as a joint of a structure, or the like. In a ground injection method for injecting an injection material into a portion to fill or stop water in the void portion, as the injection material, a cement-based solidification material such as cement milk or a chemical-solidification material such as a water glass solution is used. In addition, there is provided a ground injection method characterized by using a ground improvement material obtained by mixing short fibers containing water and causing at least surface slimming.

Hereinafter, the present invention will be described in more detail. The soil injection method according to the present invention improves the water-impregnated ground by injecting the injected material into the water-impregnated ground through which inflow water from a river or the like and groundwater pass, clogging the gap between the sediment particles and stopping the water. In the ground injection method, a short fiber containing water and causing at least surface slimming is mixed with a cement-based solidifying material such as cement milk or a chemical liquid-based solidifying material such as a water glass solution. It is characterized by using a ground improvement material made as described above.

Further, the present invention is directed to a method for injecting material into a void formed around an underground structure or in a soil structure, a crack formed in a rock or an underground structure, or a joint such as a joint of a structure. In the ground injection method for injecting and filling or stopping water in the void portion, as the injection material, water is added to a cement-based solidification material such as cement milk or a chemical liquid-based solidification material such as a water glass solution. It is characterized by using a ground improvement material obtained by mixing short fibers that cause slime at least in the surface.

The cement-based solidifying material constituting the ground improvement material used in the present invention is, for example, cement milk,
Use of various conventionally known solidifying materials as solidifying materials for soil improvement, such as cement-based fillers such as cement mortar and cement bentonite and bentonite-clay-based fillers such as bentonite, clay, bentonite cement and clay cement. Can be.

The solidifying material of the chemical chemicals may be, for example, a water glass / inorganic reaction material, a water glass / organic reaction system, a water glass injection material such as a neutral grout system, a urethane system, an acrylamide system, a urea system, or the like. Various conventionally known solidifying materials such as lignin-based or other injecting materials can be used as a solidifying material for improving the ground.

The ground improvement material used in the present invention is:
The solidified material is constituted by mixing short fibers containing moisture and causing slime at least on the surface.

According to the ground injection method of the present invention, a ground improvement material obtained by mixing short fibers containing water and causing slime at least on the surface with a solidified material is used as the injection material. The frictional resistance is reduced by the slimming of short fibers, and during pumping, it is possible to avoid clogging of the pumping pipe and injection pipe, etc., and when the injection material passes through the gap between the soil particles constituting the ground By performing the function of the slick as a lubricating material, the solidified material containing short fibers is spread over a wide area to fill the gap between the sediment particles. In addition, the short fibers, due to the intrinsic properties of the fibers, prevent the flow of the solidified material at the filling positions of the injected material and the gaps between the structures over a wide range,
The filler material can be stagnated in the filling portion, thereby preventing the filler material from being washed away by the water stream before being gelled and solidified, or diluted with the water in the ground. Furthermore, by the solidification of the short fibers in the injection material,
Short fibers function as a reinforcing material to suppress the shrinkage of the injection material,
Improves the durability of the injection material as a waterproof material.

In the ground injection method according to the present invention, it is preferable to use water-swellable fibers as the short fibers containing water and causing at least the surface to be slimmed.

Here, the water-swellable fiber is a fibrous substance having a hydrophilic cross-linked polymer in the outer layer, and the hydrophilic cross-linked polymer swells by containing water to increase its volume. Say.

By using the water-swellable fiber, the solidified material is more firmly integrated with the solidified material in the injected material, thereby firmly holding the injected material in the gap and more effectively reinforcing the water-impregnated ground. be able to.

Further, in the ground injection method of the present invention, more preferably, as the short fibers containing water and causing slime on at least the surface thereof, an inner layer serving as a core formed of an acrylic fiber and the inner layer are surrounded. A water-swellable fiber having a double structure consisting of an outer layer formed of a superabsorbent polymer as a hydrophilic cross-linked polymer disposed as described above is used.

Here, a double structure comprising a core inner layer formed of the acrylic fiber and an outer layer formed of a superabsorbent polymer as a hydrophilic cross-linked polymer disposed so as to surround the inner layer. As the water-swellable fiber, water-swellable fiber described in, for example, Japanese Patent Publication No. 58-10508 can be used, and more specifically, for example, trade name Runace (manufactured by Toyobo Co., Ltd.) or the like can be used. Can be used.

Further, the ground injection method according to the present invention is characterized in that, as the short fibers containing moisture and causing slime at least on the surface, an inner layer made of acrylic fiber and an outer layer made of a highly water-absorbing polymer are used. When using a water-swellable fiber having a heavy structure, the length of the water-swellable fiber is 1 to
It is particularly preferable to use it as 8 mm.

That is, if the length of the water-swellable fiber having the double structure is shorter than 1 mm, the effect of suppressing the pouring material from being washed away or diluted by flowing water cannot be sufficiently exhibited. When the thickness exceeds 8 mm, there may be a case where the solidification material is closed in a gap or a gap before the solidified material is filled in a sufficient range due to entanglement of fibers.

The ground injection method according to the present invention is characterized in that, as the short fibers containing water and causing slime at least on the surface, an inner layer made of acrylic fiber and an outer layer made of a highly water-absorbing polymer are used. When water-swellable fibers having a heavy structure are used, the weight ratio of the water-swellable fibers in the ground improvement material is particularly preferably 0.05 to 0.75% by weight.

That is, if the weight ratio of the water-swellable fiber having a double structure in the injection material is less than 0.05% by weight, the water stopping effect by adding the fiber cannot be sufficiently exerted. When the content exceeds 0.75% by weight, dispersibility may be deteriorated, and workability may be significantly reduced due to entanglement of fibers.

[0026]

The present invention will now be described by way of examples which were carried out to confirm the specific effects of the ground injection method of the present invention, but the present invention is not limited to these embodiments.

FIG. 1 shows a schematic configuration of a test apparatus used for each experiment in this embodiment. That is,
According to this test apparatus, the pipe 10 has, for example, an inner diameter of 20 mm.
cm, about 1m in length, and three pieces of sand, such as gravel, sand, gravel, etc.
For filling as 2 to form artificial ground,
The pipe 10 is formed of a transparent acrylic resin so that the state of water flow through the gap between the earth and sand and the state of injection and filling of the injection material can be observed.

The injection pipe 10a of the injection material formed so as to branch and protrude from the pipe 10 has one end communicating with the internal space of the pipe 10, and an injection tube 14 inserted from the other end. It penetrates to the internal space of the pipe 10.

In this embodiment, MG Rock No. 2 (manufactured by Mitsui Toatsu Chemicals Co., Ltd.) which is a two-part mixed type liquid for ground injection containing a water glass solution is used as the injection material. The other end of the injection tube 14 is divided into two branches, and connected to a storage tank (not shown) for storing the liquid A and the liquid B via a liquid sending pump 16. Each injection material stored in the pipe 1
It is designed so that it can be pumped and injected within 0. The liquid sending pump 16 is provided with a pressure gauge so that the liquid sending pressure of the liquid sending pump 16 can be checked at any time.

A water injection tube 22 is connected to one end of the pipe 10. Water supplied from a water supply facility (not shown) at a pressure of about 2 kgf / cm ² through the water injection tube 22 is supplied to the inside of the pipe 10. It flows into the artificial ground formed in the space, thereby creating an artificial flowing ground. And the water flowing into the pipe 10 is
The water is discharged through a drain tube 24 connected to the end of the pipe 10 opposite to the connection side of the water injection tube 22.

Further, pressure gauges 18 and 20 are provided on the water injection tube 22 and the drainage tube 24, respectively, for instructing measurement of the water injection pressure and the drainage pressure. It is an index that indicates

In this example, No. 5 crushed stone (13 to 20 mm in diameter) was used as the ground material 12. Table 1 shows the standard composition of MG Rock No. 2 used as the injection material.

[0033]

[Table 1] Comparative Example 1: MG Rock No. 2 having a standard composition was used as an injecting material and injected into the flowing ground at a rate of 10 liters / minute per minute. The gel time of MG Rock 2 is 13
Seconds.

The following injection conditions were obtained.

From about 30 seconds after the start of the injection, the solidified body of the MG lock was confirmed to be white from the lower side of the pipe. The injection pressure increased from 0 kgf / cm ² to 1 kgf / cm ² , but the water supply pressure did not increase.

About three minutes after the start of the injection, the lower half of the pipe was stopped by the solidified MG lock. Water injection pressure is 1kgf /
cm ² , and the water supply pressure did not rise above 0.7 kgf / cm ² .

Even if the MG lock is injected as it is, the gel body is diluted and decomposed and flows into running water, so that the volume of the consolidated body does not increase and neither the injection pressure nor the water supply pressure rises. Reduce to 40 liters per minute.

After the water was reduced, the injection pressure did not change to 1 kgf / cm ^2, and there was no change in the solidified volume of the MG lock, the injection pressure, and the water supply pressure.

Although the volume of the consolidated body increased somewhat by reducing the amount of water supply, the injection pressure did not rise above 1 kgf / cm ² , and the flow of water could not be stopped.

Even if the running water is reduced to 5 liters / minute,
Could not stop the water.

That is, it was confirmed that the running water could not be completely stopped by the MG lock alone.

Example 1: As shown in Table 2, injection material obtained by mixing 1.0% by weight of A liquid with MG Lock No. 2, that is, 0.5% of the entire MG lock with runace Was injected into the flowing ground under the same conditions as in Comparative Example 1.

[0043]

[Table 2] The following injection conditions were obtained.

From about 20 seconds after the start of the injection, the solidified material of the injection material was confirmed to be white from above the pipe. As the injection pressure increases from 2 kgf / cm ² to 3 kgf / cm ² ,
The feed pressure increased by 0.2 kgf / cm ² .

After about 2 minutes from the start of the injection, the amount of water supplied decreased, and the injection pressure increased to 4 kgf / cm ² and the water supply pressure also increased 0.4 kgf / cm ² .

In proportion to the injection amount and the injection time, the amount of the injected solid, the water supply amount, the water supply pressure, and the injection pressure also change.
About 12 minutes after the injection, the running water was completely stopped and the injection pressure was 1
When the pressure reached 0 kgf / cm ² , the injection pump was stopped.
In addition, the filling range of the injection material is set at 1. downstream from the injection port.
0 m and 0.7 m in the upstream direction for a total of 1.7 m.

That is, it was confirmed that running water could be stopped in an appropriate injection range by using an injection material obtained by adding Runace to MG Rock No. 2 (0.5% by weight).

Example 2: For the injection material in which 1.0% or 1.5% by weight of Runace was added to Solution A, respectively, to MG Rock No. 2 having a standard composition shown in Tables 3 and 4, Table 5 shows the results of tests performed on the adaptability of pumping. In addition, SG-40 (manufactured by Shin-Meiwa Co., Ltd.) was used as the infusion pump, and the inner diameter was 19 m as the infusion hose.
m medium pressure hose was used.

[0049]

[Table 3]

[Table 4]

[Table 5] From the test results shown in Table 5, it was found that even when 1.5% of Run Ace was added to Solution A, there was no problem in the pumpability of the injected material.

Example 3: When the injection material according to this example is injected into a fine gravel soil having a particle size of about 2 to 3 mm,
Since it is considered that the injection pressure is significantly increased and injection is difficult, the relationship between the length of the injectable fiber and the diameter of the gravel was estimated from the results of various experiments as follows.

(D / L)> 1-2 Here, d: gravel diameter (mm), L: fiber length (mm) Therefore, in this experiment, a run-ace having a fiber length of 1 mm was used, and its injection into the gravel soil was performed. Verification of water resistance and water stopping performance. In the initial stage of the injection, the injection property at the time of adding the run ace is confirmed only with the liquid A (water glass solution) without using the hardening agent, and then injected together with the hardening agent. Further, the experimental model is the same as the above-mentioned Comparative Example 1 and Example 1,
The same acrylic pipe as in the case of 2 was used, and the hydraulic conductivity estimated from the pressure gradient at the time of water flow in the test apparatus was 1 ×
10 ⁰ <k <1 × 10 ⁻¹ (cm / s).

Table 6 shows the experimental results.

[0053]

[Table 6] From the results in Table 6, it was found that, in the case of fine gravel, by shortening the fiber length, the injectability was improved, and the effect of adding runace to the water stopping performance of the injected material was also recognized.

[0054]

As described in detail in the above embodiments, according to the ground injection method according to the present invention, as an injection material, a cement-based solidifying material such as cement milk or a chemical-chemical solution such as a water glass solution is used. Since the ground improvement material obtained by mixing at least the surface of the solidified material with short fibers containing moisture and causing slimming is used, the frictional resistance during the injection of the injection material containing the short fibers is reduced by the slimming of the short fibers. When the injected material passes through the gaps between the soil particles that compose the ground and the gaps between the structures, the slime functions as a lubricating material to stop the water and improve the ground or block the gaps. Injected material containing solidified material and short fiber was spread over a wide range sufficiently and uniformly to the extent that it should be, and the desired water stopping effect and ground reinforcing effect or blocking effect, or around the structure, etc. It can be easily obtained filling effect of space.

If the water-swellable fibers are used as the short fibers containing water and causing at least the surface to be slicked, the water-swellable fibers are more firmly integrated with the solidified material in the injection material, and the injection material is inserted into the gap. By firmly holding the ground, the stagnant ground and voids can be reinforced more effectively.

Further, the length of the water-swellable fiber is set to 1 to
If it is used as 8mm, by selecting an appropriate fiber length in flowing ground with large gaps such as gravel ground,
It is possible to reduce the influence of runoff or dilution of the injection material due to groundwater flow or the like, and to add the water-swellable fiber to the ground improvement material by adding the weight ratio of the water-swellable fiber to 0.05 to
When used as 0.75% by weight, it is possible to inject the sediment particles without clogging in a pump or a hose or clogging the gap between the earth and sand particles before the injection material sufficiently spreads in a predetermined range.

[Brief description of the drawings]

FIG. 1 is a side view showing a schematic configuration of a test apparatus used in an experiment performed to confirm a specific effect of the ground injection method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Pipe 12 Ground material 10a Injection pipe 16 Pump for sending liquid

Continuation of front page (56) References JP-A-5-65711 (JP, A) JP-A-5-345652 (JP, A) JP-A-5-132924 (JP, A) JP-A-5-140926 (JP) , A) JP-A-51-2211 (JP, A) JP-B-58-10508 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) E02D 3/12 101

Claims (5)

(57) [Claims] An injection material is injected into a stagnant ground through which inflow water or groundwater from a river or the like passes, and the gap between the sediment particles is clogged and water is stopped to improve the stagnant ground. In the ground pouring method, as the pouring material, a cement-based solidifying material such as cement milk or a chemical liquid-based solidifying material such as a water glass solution is mixed with short fibers containing water and causing at least the surface to become slimy. A ground injection method characterized by using a ground improvement material. 2. Injection material is injected into voids around the underground structure or in the soil structure, cracks and cracks in the rock or underground structure, and joints of the structure. In the ground injection method for filling or stopping water in the void portion, as the injection material, a cement-based solidification material such as cement milk or a chemical liquid-based solidification material such as a water glass solution contains at least a surface containing water. A ground injection method characterized by using a ground improvement material obtained by mixing short fibers that cause slime. 3. The soil injection method according to claim 1, wherein the short fibers containing water and causing at least surface slimming are water-swellable fibers. 4. The method according to claim 3, wherein the length of the short fibers mixed with the solidified material is 1 to 8 mm. 5. The ground injection method according to claim 3, wherein the weight ratio of the short fibers in the ground improvement material is 0.05 to 0.75% by weight.