JP2821049B2 - Ground injection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can stop water even on a ground such as a flowing ground where an injected material is unlikely to stay, can easily adjust the time from injection to water stoppage, and can reduce the environment such as soil contamination. It relates to the ground injection method with less influence.

[0002]

2. Description of the Related Art Conventionally, a cement-based material such as cement milk or a chemical solution-based material such as LW has been used as an injection material for soil improvement. These injection materials are
It is injected into the gap in the ground to reduce the water permeability of the ground or to improve the ground strength. In addition, when injecting these injection materials into the ground, the main agent and the hardener are mixed at a predetermined ratio so as to adjust the time from injection into the ground to solidification, so-called gel time, in a predetermined ratio. And a curing agent are mainly injected from a Y-tube into the ground.

[0003]

However, in the above-mentioned method of injecting an injecting material, when the injecting material is injected into a flowing ground where water flows, the injecting material flows into the water flow and flows away. In some cases, the intended purpose of the ground improvement described above is not fulfilled, for example, because the injected material is not solidified due to being diluted with water in the ground before solidification. In addition, in particular, when a chemical solution is used, there is also a problem that even if the chemical solution is sufficiently solidified, components in the chemical solution may remain in the injected ground and cause soil contamination.

[0004] The present invention has been made in view of the above problems, and an object of the present invention is to stop water even on a ground such as a flowing water ground where an infused material is unlikely to stay. It is an object of the present invention to provide a ground injection method which can be easily adjusted and has less influence on the environment such as soil contamination.

[0005]

In order to achieve the above-mentioned object, the present invention relates to a ground injection method for injecting an injection material through an injection pipe penetrating into the ground, wherein a water-swellable fiber is used as the injection material. It is characterized by using a fiber dispersion liquid dispersed in water.

Further, it is desirable to add an electrolyte to the injection material in the present invention.

[0007]

According to the above construction, the fiber dispersion of the water-swellable fiber as the injecting material is injected into the ground by a one-shot injecting method via an injecting pipe in the same manner as in the conventional injecting material, and contained. As the water-swellable fibers move through the ground due to the water flow, they swell while entangled with the surrounding gravel, gravel, etc., and cut off the flowing water channel in the ground, so that they do not flow down into the ground unlike conventional injection materials. A reliable water stopping effect can be obtained.

Further, by increasing or decreasing the amount of the electrolyte added to the fiber dispersion of the water-swellable fiber, the time until the water-swellable fiber starts to swell, ie, the gel time, can be adjusted. In this case, the gel time becomes longer as the concentration of the electrolyte increases.

Further, since the water-swellable fibers do not elute substances that cause residual pollution, they are less likely to cause environmental pollution such as soil pollution. Such fibers include, for example, synthetic fibers, semi-synthetic fibers, and regenerated fibers.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic system diagram of a test facility used to confirm the effect of the ground injection method according to the present invention. The pipe 10 has an artificial ground material 1 such as gravel and gravel in its internal space.
2 to form an artificial ground. The pipe 10 is formed of a transparent acrylic resin so that the internal water flow and the state of injection of the water-swellable fibers can be observed.

An injection pipe 10a formed so as to branch and protrude from the pipe 10 is a one-shot injection pipe for injecting a water-swellable fiber dispersion into an artificial ground formed in the internal space of the pipe 10. It is provided as
One end thereof communicates with the internal space of the pipe 10, and the injection tube 14 is inserted from the other end, and is inserted into the internal space of the pipe 10. The other end of the injection tube 14 is connected to a water swellable fiber dispersion storage tank (not shown) via a liquid supply pump 16, and the water swellable fiber dispersion stored in the storage tank is piped. 10
It can be pumped and injected into the inside. The liquid supply pump 16 is provided with a pressure gauge.
Can be checked at any time.

At one end of the pipe 10, a water injection tube 2 is provided.
2 are connected. Water with a water pressure of 2 kgf / cm ² sent from a water supply facility (not shown) through the water injection tube 22 flows into the artificial ground formed in the internal space of the pipe 10,
This will create artificial running ground.

The water flowing into the pipe 10 is
Is discharged through a drain tube 24 connected to the end of the water injection tube 22 opposite to the connection side.

The pressure gauges 18 and 20 provided on each of the water injection tube 22 and the drainage tube 24 measure and instruct the water injection pressure and the drainage pressure. It will be an indicator of the water stoppage situation. In this test, the difference between the two indicated values was 2 kgf / cm ²
When it reached, it was determined that the water was completely stopped.

A test for confirming the effect was conducted by the test facility for the ground injection method according to the present invention having the above-described configuration.

As the water-swellable fiber used for the injecting material, there is, for example, one disclosed in Japanese Patent Publication No. 58-10508. And a water-swellable fiber (trade name: Lanseal, manufactured by Toyobo Co., Ltd.) having an outer layer, which is disposed so as to surround the inner layer, and has been processed so as to swell after absorbing water. Adopted. This water-swellable fiber is a composite functional fiber having both functions as a fiber of the core acrylic fiber and a function as a highly water-absorbing polymer of the outer layer. As for environmental safety, it does not contain residual components that cause soil contamination, and is safe for living organisms.

KOH, NaOH, NaCl, Na ₂ S are used as swelling regulators for adjusting the gel time.
Although an electrolyte such as O ₄ is used, NaCl, which is the most easily available and safe in this test, was used.

Using the above test equipment and the injection material, a test for confirming the effect of the ground injection method according to the present invention was conducted.

First Embodiment: An artificial ground is formed by filling the inside of a pipe 10 with gravel having a diameter of 20 to 30 mm as an artificial ground material 12, and about 40 liters / minute of water is poured into the pipe 1.
Water was allowed to flow through the inside of the vessel to create artificial running ground. As the injecting material, a 2% by weight dispersion of water-swellable fibers obtained by mixing 8 mm long fibers and 3 mm long fibers in half was used. In addition, a 2% by weight aqueous solution of NaCl was used as a swelling regulator.

Second Embodiment: An artificial ground is formed by filling the inside of a pipe 10 with a gravel having a diameter of about 5 mm as an artificial ground material 12, and passing about 40 liters / minute of water through the pipe 10. , And artificial running ground. As the injecting material, a 1% by weight dispersion of water-swellable fibers having a length of 3 mm was used. In addition, a 1% by weight aqueous solution of NaCl was used as a swelling regulator.

Third Embodiment: An artificial ground is formed by filling the inside of a pipe 10 with gravel having a diameter of about 2.5 mm as an artificial ground material 12 and passing about 40 l / min of water through the pipe 10. Then, it was made artificial groundwater. As the injection material, a water-swellable fiber of a 3 mm long fiber was used for 0.5
A weight percent dispersion was used. Also,
0.5% by weight of NaCl
An aqueous solution was used.

Fourth embodiment: As in the first embodiment, 8 mm
Length and 3 mm length water-swellable fiber were mixed by 1/2
To a 2% by weight dispersion and swell
No electrolyte as a regulator was added at all.

Here, the gel time and the injection range volume will be described. Highly water-absorbing water-swellable fibers do not swell in the presence of an electrolyte because their water-absorbing ability is suppressed. When such a dispersion of the water-swellable fibers containing the electrolyte is injected into the flowing water ground, the electrolyte is flown by the flowing water, and the surroundings of the water-swellable fibers are replaced with water containing no electrolyte. At this point, water absorption of the water-swellable fiber starts, and the water-swellable fiber swells. The time from the injection to the start of water absorption swelling is called gel time. If this time, that is, the gel time is long, the gap between the grounds is plugged after the fiber dispersion liquid is flowed far before the fiber dispersion liquid is injected and swelled at first, so that the volume of the ground water blocking area becomes large. The first embodiment to the fourth
The test results of the examples are summarized in Table 1.

[0024]

In the first embodiment, the condition is that the gap in the artificial ground is the largest and the water permeability is also the largest. In this embodiment, 3 mm and 8 mm long water-swellable fibers are mixed, and the NaCl concentration is 2% by weight. Because of the largest gap in the artificial ground and the largest NaCl concentration and therefore the longest gel time, the injection range volume is the largest of the three examples.

In the second embodiment, the gap in the artificial ground is smaller than that in the first embodiment, and thus the water permeability is slightly smaller. In this embodiment, the concentration of the water-swellable fiber is reduced, and only the short fiber having a length of 3 mm is used. In addition, the concentration of NaCl is also 1% by weight. The injection area volume was about 20% less than in the case of the first example, and water was completely stopped.

In the third embodiment, the water swellable fiber and the concentration of NaCl are both lower than those in the second embodiment under the condition assuming a ground having further low water permeability. Since the gap in the artificial ground was small, the injection range volume was about 1/3 to 1/4 of that in the first and second embodiments, but water was completely stopped.

In the fourth embodiment, dispersion is performed in a storage tank.
Fibers are swollen by water absorption, resulting in high viscosity fibers as a whole.
It became a dispersion. This fiber dispersion is supplied to the pump 16 for feeding liquid.
Pumping cannot be performed unless the pressure of the liquid is increased, and the water area in the artificial ground
Immediately after injection into the ground, clogging of the gaps in the artificial ground began.
In other words, although water can be stopped, the injection area volume is small,
The state was not good compared with the first example.

However, in this embodiment, the required stoppage is
It is considered that it can be used depending on the water conditions.

Next, a comparative example of the first to fourth embodiments will be described.

In the first and second comparative examples described below, the same test equipment is used as in the above-described embodiment, and the diameter of each comparative example is the same as that in the first embodiment.
The artificial ground was formed by 30 mm of gravel.

First Comparative Example: Cement milk was injected from the injection tube 14, but when it reached the flowing water area in the artificial ground, the injected material was washed away and water could not be stopped at all.

Second Comparative Example: Polyester fibers, which are non-swellable fibers, were 3 mm long and 8 mm long and dispersed in water at 2% by weight in the same manner as in the above example. No liquid was obtained, and it was difficult to inject with the liquid sending pump 16. Partial pipe 10
What could be injected into the inside also clogged near the outlet of the injection tube 14 and did not stop. First comparative example-
Table 2 summarizes the test results of the second comparative example.

[0034]

Through the above-described test, in order to effectively stop water from permeable ground such as flowing ground, water-swellable fibers are injected into a wide area of the ground and then sufficiently swollen. It turned out to be necessary. In order to satisfy such conditions, the adjustment of the gel time is important, and the lubricating action of the water-swellable fiber, which is developed with the swelling of the water-swellable fiber, makes the water-swellable fiber reach a wider range. It was known that it contributed to
That is, when the water-swellable fiber swells,
When the injection material is pumped by a pump etc.
Prevents the pumping tube from clogging due to the effect of fiber
At the time of injection into the ground,
Reduce frictional resistance with constituent sand, gravel, gravel and other particles
Acts as a lubricating material, which allows
Permeability of injected material due to the inclusion of fibers as foreign matter
Can be suppressed. Concerning the swelling of the water-swellable fibers and the lubricating action associated with the swelling of the water-swellable fibers due to such dilution of the electrolyte concentration, it is necessary to appropriately control the contradictory conditions. It is considered that about 0.5 to 2% by weight is appropriate as the NaCl concentration for the conductive fiber. The water-swellable fiber is the fiber.
Reinforcing material that suppresses shrinkage of injected material due to its inherent properties
Functions as a filler and improves the durability of the injection material as a water stopping agent
You.

[0036]

As described in detail in the above embodiments, according to the ground injection method according to the present invention, the dispersion of the water-swellable fiber as the injection material is supplied to the injection pipe similarly to the conventional injection material. Water is injected into the ground through the ground, and while the water-swellable fibers contained in the ground move through the ground due to the water flow, they swell while being entangled with the surrounding gravel, gravel, etc., and cut off the flowing water channel in the ground. A reliable water stopping effect can be obtained without spilling into the flowing ground unlike materials.

By increasing or decreasing the amount of the electrolyte added to the dispersion of the water-swellable fiber, the time until the water-swellable fiber starts to swell, ie, the gel time, can be adjusted. Can be set so that is injected over a wider range.

Furthermore, the water-swellable fibers are processed products such as synthetic fibers, semi-synthetic fibers, and regenerated fibers, and do not elute substances that cause residual contamination, and may cause environmental pollution such as soil pollution. Less is.

[Brief description of the drawings]

FIG. 1 is a schematic system diagram showing test equipment for a ground injection method according to the present invention.

[Explanation of symbols]

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

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Fujio Ito 2-3-3 Kandaji-cho, Chiyoda-ku, Tokyo Obayashi Corporation Tokyo Head Office (72) Inventor Eiichi Taki 2-2-2 Dojimahama, Kita-ku, Osaka-shi, Osaka No.8 Toyobo Co., Ltd. Head Office (56) References JP-A-1-142119 (JP, A) JP-B-58-10508 (JP, B2) Fusayoshi Masuda, "Polymer New Material OnePoint4 High Absorbent Polymer" 1st Edition, Kyoritsu Shuppan, published November 15, 1987, p. 22-23 (58) Fields investigated (Int. Cl. ⁶ , DB name) E02D 3/12 E02D 19/16

Claims (2)

(57) [Claims] 1. A ground injection method in which an injection material is injected through an injection pipe penetrating into the ground, wherein a fiber dispersion liquid in which water-swellable fibers are dispersed in water is used as the injection material. Ground injection method. 2. The method according to claim 1, wherein an electrolyte is added to the injection material.