JP2002038470A - Pile foundation construction method in waste disposal plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To construct a pile while preventing diffusion of pollutants to the peripheral environment. SOLUTION: In the pile foundation construction method in a waste disposal plant, piles 7 formed of a hollow pipe in which hardener delivery holes 6 are formed at the side are driven in the waste disposal plant 1 (step 101) and then, a specified filler 9 is charged from injection inlet 10 provided at the end of the ground surface side so that the upper level of the filler is lower than the level of an impervious structure 3 (step 102). Subsequently, an electric source 23 impressing direct voltage is connected to the cathode 21 installed in the pile 7 and the anode 22 installed at the outside of the pile and in the vicinity of the penetration position of the impervious structure 3 (step 103). Nextly the electric source 23 is made to work so as to energize between the cathode 21 and the anode 22 while the fluid hardner 11 having the same polarity as the cathode 21 is being filled (step 104).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of constructing a pile foundation for constructing a new structure at a site of a waste disposal site.

[0002]

2. Description of the Related Art In a waste disposal site for landfilling industrial waste and general waste, a seepage control method is used to prevent contaminated water oozing from stored waste from diffusing into the environment such as groundwater. Must be applied.

[0003] As such a water-blocking work, an impermeable layer or a poorly permeable layer which exists naturally in the ground may be used as it is, but it is difficult to secure a suitable place. In some cases, a water-blocking sheet made of a soft synthetic resin, rubber, or the like is laid to form a water-blocking structure.

[0004] On the other hand, after the landfill at such a waste disposal site is completed, it is desirable that the site is effectively used for various purposes.

[0005]

Here, when constructing a new structure for use at the site of a waste disposal site, the ground strength of the site may be insufficient.
It is necessary to adopt a pile foundation as the foundation of the structure.

[0006] However, in a situation where such a pile is driven so as to penetrate through the impermeable structure of the waste disposal site, which causes a gap between the impermeable structure and the pile, There has been a problem that the seepage water in the waste disposal site leaks to the outside and spreads to the surrounding ground to cause a concern that the environment is polluted.

[0007] For this reason, when constructing a structure on the site of a waste disposal site, the structure must be limited to a structure that does not use piles.

The present invention has been made in view of the above-mentioned circumstances, and provides a method of constructing a pile foundation in a waste disposal site capable of constructing a pile while preventing a contaminant from diffusing into a surrounding environment. The purpose is to provide.

[0009]

In order to achieve the above object, a method for constructing a pile foundation in a waste disposal site according to the present invention has a solidified material discharge hole formed laterally as described in claim 1. A pile composed of a hollow tube is driven into the waste disposal site so that the pile penetrates a water-impervious structure provided on the bottom surface of the waste disposal site, and a first electrode installed in the pile and the pile Outside, and applying a DC voltage between the second electrode and the second electrode installed near the penetrating portion of the water-blocking structure, and conducting the current from the injection port provided at the ground side end of the pile. A fluid solidifying material having the same polarity as that of the first electrode is injected.

Further, in the method for constructing a pile foundation in a waste disposal site according to the present invention, after the pile is driven, a predetermined filling material is moved so that its top end is lower than the height position of the water-blocking structure. The fluid solidifying material is injected from the injection port so as to be as soon as possible.

In the method for constructing a pile foundation in a waste disposal site according to the present invention, a predetermined space occupant is kept in a non-contact state with the solidified material discharge hole before the fluidized solidified material is solidified. As described above.

In the method for constructing a pile foundation in a waste disposal site according to the present invention, a pile composed of a hollow tube having a solidified material discharge hole formed on the side is provided on the bottom surface of the waste disposal site. It is driven into a waste disposal site so as to penetrate the impermeable structure, and then a first electrode installed in the pile and a second electrode installed outside the pile and near a penetration point of the impermeable structure. DC voltage is applied between the electrodes. Then, a fluid solidifying material having the same polarity as that of the first electrode is injected from an injection port provided at an end of the pile on the ground side while performing the energizing operation continuously or intermittently.

With this configuration, the flowable solidified material injected from the injection port provided at the ground-side end of the hollow tube is attracted to the second electrode having a different polarity, that is, the electric current is generated by energization. It passes through the solidified material discharge hole due to the migration effect. And since the 2nd electrode is installed in the vicinity of the penetration part of a water impervious structure, the fluid solidification material discharged around the pile is inserted into the gap between the water impervious structure generated when driving the pile. It is filled and eventually hardens in the gap, closing it.

In particular, in the present invention, a large gap is formed around the pile, or the pile has a shallow depth and the weight of the fluid solidified material is small, so that the gap is reliably filled with the fluid solidified material. Even in the case where it is difficult to carry out, it is possible to reliably fill the gap with the flowable solidifying material by the electrophoretic action by energization.

[0015] A waste disposal site refers to a facility in which substances that may adversely affect the environment due to diffusion are separated from the surrounding ground by a water-blocking structure, and is generally referred to as an industrial waste disposal site. As well as facilities that contain contaminated soil.

The impermeable structure has a function of separating the buried space in the waste disposal site from the surrounding ground with a predetermined water tightness. Includes water-impervious sheets, etc., which have been laid in a special manner.

The shape and material of the hollow tube used as a pile are arbitrary, as long as it has a hollow space, and the tip of the pile may be open or closed. It is possible.

The inlet may be an opening at the end of the hollow tube itself, or an opening may be provided separately on the side of the hollow tube and used as the inlet.

The fluid solidifying material is any material that is not electrically neutral, that is, ionic, as long as it has fluidity and exhibits water-stopping property by solidifying. The choice is optional. Examples of anionic ones include water glass, Portland cement, suspension-type water glass-based injectables mainly composed of bentonite, water glass, sodium hydrogen carbonate, calcium chloride, and the like. A solution-type water glass-based injecting agent having a main component such as the above may be used, and an acrylate-based one may be used as the cationic one.

The solidified material discharge hole may be a circular hole of several mm to several cm, but the size, number, etc. may be appropriately determined in consideration of the required discharge amount of the fluidized solidified material, the fluidity, and the like.
Further, the solidified material discharge hole is formed at a position where the flowable solidified material discharged from the solidified material discharge hole is filled in a gap formed between the impermeable structure of the waste disposal site and the pile. It is necessary to correspond to the height position of the impermeable structure.However, for example, by referring to the measurement results of the boring survey conducted when constructing the waste disposal site, It is conceivable that the height position is grasped, and the formation position of the solidified material discharge hole and the pile driving depth are determined in consideration of the measurement result.

How to inject the flowable solidifying material as long as the flowable solidifying material discharged from the solidification material discharge hole is filled in the gap formed between the impermeable structure of the waste disposal site and the pile. However, for example, the solidifying material may be injected until it overflows from the ground side opening of the pile. The injection may be performed until it is higher than the height position. In such a case, the post-treatment of the upper space after the injection of the fluidized solidifying agent is optional, and it is conceivable that the post-treatment is left in a hollow state.

The first electrode and the second electrode are not particularly limited in the configuration and arrangement as long as the fluidized solidifying material can be discharged from the solidified material discharge hole by the electrophoretic action by energization. It is conceivable to attach them to the outer peripheral surface and the inner peripheral surface of the hollow pipe near the height position of the water shielding structure, respectively. It goes without saying that which of the first electrode and the second electrode is used as the anode or the cathode is arbitrary. When the first electrode is an anode and the second electrode is a cathode, a cationic solidifying material is used as the fluidized solidifying material. And

The first electrode and the second electrode may be installed at any point in time, and may be inserted and installed at the site after the pile is driven. May be pre-assigned. In addition,
In the case of pre-attaching, it is desirable that the second electrode is previously buried in the outer peripheral surface of the pile so as not to hinder the pile driving operation.

[0024] Here, after the pile is driven, a predetermined filler is injected from the inlet so that the top of the filler is lower than the height position of the impermeable structure. If the solidifying material is configured to be injected, the flowable solidifying material is not required by the amount of the filler, so that the injection amount of the liquidifying solidifying material can be reduced.

What kind of material is used as the filler is optional. For example, earth and sand, concrete, soil cement and the like can be used.

The method of charging the filler is optional. For example, the filling height is determined from the height position of the water-blocking structure and the driving depth of the pile, and the hollow sectional area of the pile is determined by the charging height. May be calculated in advance by multiplying by, and the filler corresponding to the input amount may be charged.

Also, if the predetermined space occupying member is arranged inside the pile so that the non-contact state with the solidified material discharge hole is maintained before the fluidized solidified material is solidified. , Only the volume excluded by the space occupant,
No fluid solidifying material is required. Therefore, for example, when the pile diameter is large, it is possible to greatly reduce the injection amount of the fluidized solidifying material while enjoying the above-described operation and effect of the filling with the fluidized solidifying material.

The space occupant may be of any type as long as it can reduce the injection amount of the flowable solidifying material when installed inside the pile, and may be hollow or solid. It does not matter. For example, it is possible to form a hollow steel pipe of a predetermined length with lids attached to the upper and lower ends so that the flowable solidifying material does not flow into the inside.

The space occupying member may be provided before the solidifying material is solidified, and may be provided before, during, or after the injection of the solidifying material.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a pile foundation construction method in a waste disposal site according to the present invention will be described below with reference to the accompanying drawings. It is to be noted that the same reference numerals are given to components and the like that are substantially the same as those in the conventional technology, and description thereof will be omitted.

FIG. 1 is a flowchart showing a method for constructing a pile foundation in a waste disposal site according to the present embodiment, and FIGS. 2 and 4 are construction procedure diagrams showing how a pile foundation is constructed according to the flowchart. In the waste disposal site 1 according to the present embodiment, as shown in FIG. 2A, the landfill space 2 is separated from the water-permeable formation 4 that is the surrounding ground by a water-impermeable structure 3 made of an impermeable formation. It becomes.

In the method for constructing a pile foundation in the waste disposal site 1 according to the present embodiment, first, as shown in FIG. 2 (a), the method comprises a hollow tube having a solidified material discharge hole 6 formed on the side. The pile 7 is driven into the waste disposal site 1 (step 101). At this time, the pile 7 penetrates the water-blocking structure 3 provided on the bottom surface of the waste disposal site 1, and a gap 8 is generated between the water-blocking structure 3 and the pile 7. If the pile 7 is not a friction pile but a support pile, the lower end of the pile 7 reaches the support base 5 as shown in FIG.

As the hollow tube used as the pile 7, a circular steel tube having an open end can be used as shown in FIG.

Solidification material discharge hole 6 to be formed on the side of pile 7
It is necessary to make the formation position correspond to the height position of the impermeable structure 3. For this, for example, a measurement result of a boring survey performed when constructing the waste disposal site 1 is referred to. By grasping the height position of the impermeable structure 3,
The formation position of the solidified material discharge hole 6 and the driving depth of the pile 7 may be determined in consideration of the measurement result.

FIGS. 3A and 3B are detailed views showing the pile 7 according to the present embodiment. FIG. 3A is a side view showing a part of the pile 7 in a sectional view, and FIG. 3B is a horizontal sectional view taken along the line AA. As shown in the figure, a cathode 21 serving as a first electrode is attached to the inner peripheral surface of the pile 7, and a second electrode is provided on the outer peripheral surface of the pile 7 near the penetration point of the water-blocking structure 3. Is attached in advance.

Here, the cathode 21 is constituted by a hollow tube having an outer diameter equal to the inner diameter of the pile 7, and the anode 22 is installed so as not to block the solidified material discharge hole 6. When the pile 7 is formed of a hollow steel pipe, an electrical insulator is appropriately interposed between the cathode 21 and the anode 22 and the pile 7.

Next, as shown in FIG. 2 (b), a predetermined filling material 9 is placed on the ground-side end of the pile 7 so that the height of the top is lower than the height position of the impermeable structure 3. Inlet 10 provided in
(Step 102).

As the filler 9, it is desirable to use, for example, earth and sand, soil cement, or the like.

[0039] When turning on the filler 9, for example, determined poured height h _a of the driving depth of the height and pile 7 of water-impervious structure 3, hollow sectional pile 7 to the put the height h _a The input amount of the filler 9 may be calculated in advance by multiplying the area, and the filler 9 corresponding to the input amount may be input.

Next, as shown in FIG. 4 (a), a DC voltage is applied to a cathode 21 installed in the pile 7 and an anode 22 installed outside the pile 7 and near the penetration of the water-blocking structure 3. Is connected (step 103).

Next, as shown in FIG. 4 (b), the power source 23 is operated to supply a current between the cathode 21 and the anode 23, and the fluid solidifying material 11 having the same polarity as the cathode 21 is injected from the injection port 10. (Step 104).

As the fluidized solidifying material 11, an anionic injecting material having fluidity and exhibiting a water stopping property by solidifying, for example, bentonite can be used.

The solidified material discharge hole 6 for discharging the fluidized solidified material 11 may be a circular hole of several mm to several cm, but the fluidized solidified material 1 discharged from the solidified material discharge hole 6 can be used.
In order to fill the gap 8 formed between the impermeable structure 3 and the pile 7, the size, the number, and the like are appropriately determined in consideration of the required discharge amount and the fluidity of the fluid solidifying material 11. Good.

When the fluidized solidifying material 11 is injected, the injection height h _{b is set} to the height of the top after injection, and
Is set as appropriate so as to be higher than the height position. After the injection of the fluid solidifying material 11, the cathode 21 and the anode 22 may be left as they are.

FIG. 5 shows a waste disposal site 1 according to this embodiment.
FIG. 5 is a view showing the operation of the pile foundation construction method in the embodiment, and as described above, the injection port 1 provided at the ground side end of the hollow tube.
The fluidized solid material 11 injected from 0 is attracted to the anodes 22 having different polarities, that is, passes through the solidified material discharge holes 6 by electrophoresis due to energization. Since the anode 22 is installed in the vicinity of the penetrating portion of the water shielding structure 3, the fluidized solid material 11 discharged around the pile 7 is discharged.
Is filled in the gap 8 between the impervious structure 3 generated when the pile 7 is driven in, and then hardens in the gap 8 and closes it.

As described above, according to the method of constructing the pile foundation in the waste disposal site 1 according to the present embodiment, the pile 7 is driven so as to penetrate through the impermeable structure 3 of the waste disposal site 1. Therefore, even if a gap 8 is formed between the solid waste material and the water shielding structure 3, the gap 8 is filled with the flowable solidifying material 11 and the water shielding function of the waste disposal site 1 is maintained. Thus, it is possible to prevent a situation in which the seepage water in the waste disposal site 1 leaks from the gap 8 to the outside and diffuses into the surrounding ground to pollute the environment.

In particular, according to the present embodiment, a large gap 8 is formed around the pile 7, and the pile 7 has a shallow depth and the self-weight of the flowable solidifying material 11 is small, so that the pile 7 has Even when it is difficult to reliably fill the solidifying material 11, it is possible to reliably fill the gap 8 with the fluidizing material 11 by the electrophoresis effect of energization.

Therefore, it is possible to newly construct a pile foundation structure at the site of the waste disposal site 1, and the application of the effective use of the site is expanded.

Further, according to the pile foundation construction method in the waste disposal site 1 according to the present embodiment, the height of the top of the predetermined filler 9 is lower than the height position of the impermeable structure 3. Since the filler 9 is charged through the injection port 10, the flowable solidification material 11 is not required by the amount of the filler 9 supplied, and
The amount of injection can be saved.

Although not particularly mentioned in the present embodiment, for example, in the case where the pile diameter is large, as shown in FIG. May be arranged inside the pile 7 so that the non-contact state with the solidified material discharge hole 6 is maintained.

With this configuration, the space occupant 4
Since the fluid solidifying material 11 is not required by the volume excluded by 1, the injection amount of the fluid solidifying material 11 can be further reduced while enjoying the above-described operation and effect by filling the fluid solidifying material 11. Becomes possible.

The space occupying member 41 may be of any type as long as it can reduce the injection amount of the flowable solidifying material 11 when installed inside the pile. It doesn't matter if it's solid. For example, as shown in FIG. 6 (a), it is possible to form a hollow steel pipe having a predetermined length with lids attached to upper and lower ends so that the fluidized solidifying material 11 does not flow into the inside.

The space occupying member may be provided before the solidifying material is solidified, and may be provided before, during, or after the injection of the solidifying material.

In the present embodiment, the present invention is applied to the water-impervious structure 3 composed of a water-impermeable stratum. The present invention may be applied to In such a case, the same operation and effect as those of the above-described embodiment can be obtained.

In the present embodiment, the filler 9 is
Is used to save the amount of the fluidized solidifying material 11, but in some cases, the filler 9 may be omitted as shown in FIG. 6 (b).

Further, in the present embodiment, the anode 22 is formed so as to protrude from the outer peripheral surface of the pile 7. It may be embedded in the surface.

In the present embodiment, the cathode 21 and the anode 22 are pre-attached before the pile is driven. However, after the pile is driven, the cathode 21 and the anode 22 may be inserted and installed on site.

In this embodiment, the first electrode is used as the cathode 2
1, the second electrode is an anode 22, and the fluid solidifying material 11 is an anionic bentonite in accordance with the first electrode. In some cases, the first electrode is an anode and the second electrode is a cathode. The fluidized solidifying material 11 may be a cationic suspension-type water glass-based injection agent or a solution-type water glass-based injection agent.

[0059]

As described above, according to the method for constructing a pile foundation in a waste disposal site according to the present invention, the pile is driven into the water impervious structure of the waste disposal site. Even if there is a gap between the impermeable structure,
Such a gap is filled with the fluidized solidifying material, and the water shielding function of the waste disposal site is maintained as it is. Thus, seepage water in the waste disposal site leaks from such a gap to the outside, and this It is possible to prevent a situation in which the environment spreads to the ground and pollutes the environment.

[0060]

[Brief description of the drawings]

FIG. 1 is a flowchart showing a pile foundation construction method in a waste disposal site according to the present embodiment.

FIG. 2 is a diagram showing an operation procedure of a pile foundation construction method in a waste disposal site according to the embodiment.

FIG. 3 is a detailed view showing a pile used in a pile foundation construction method in a waste disposal site according to the present embodiment, (a) is a side view showing a part of the pile, and (b) is a line AA. Horizontal sectional view along.

FIG. 4 is a view showing an operation procedure of a pile foundation construction method in a waste disposal site according to the embodiment.

FIG. 5 is a view showing the operation of the pile foundation construction method in the waste disposal site according to the embodiment.

FIG. 6 is a diagram showing a pile foundation construction method in a waste disposal site according to a modification of the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Waste disposal site 3 Water-blocking structure 6 Solidification material discharge hole 7 Pile 9 Filling material 10 Injection port 11 Fluidized solidification material 21 Cathode (first electrode) 22 Anode (second electrode) 41 Space occupant

 ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Haruhiko Fujii 2- 15-2 Konan, Minato-ku, Tokyo Obayashi Corporation Tokyo head office F-term (reference) 2D041 AA02 DB02 2D046 CA01 4D004 AA46 BB04

Claims (3)

[Claims] 1. A pile comprising a hollow tube having a solidified material discharge hole formed on a side thereof is inserted into the waste disposal site so that the pile penetrates a water-blocking structure provided on a bottom surface of the waste disposal site. Press,
The pile is energized by applying a DC voltage between a first electrode installed in the pile and a second electrode outside the pile and near a penetrating portion of the water-blocking structure. A method of constructing a pile foundation in a waste disposal site, comprising: injecting a fluid solidifying material having the same polarity as that of the first electrode from an inlet provided at a ground side end of the pile. 2. After the pile is driven, a predetermined filler is introduced from the inlet so that a top end of the filler is lower than a height position of the impermeable structure. The method for constructing a pile foundation in a waste disposal site according to claim 1, wherein the solidifying material is injected. 3. The disposal according to claim 2, wherein a predetermined space occupant is disposed inside the pile so that a non-contact state with the solidified material discharge hole is maintained before the fluidized solidified material is solidified. Construction method of pile foundation at waste disposal site.