JPH05256092A - Water permeable granulated composition used for backfilling - Google Patents

Abstract

PURPOSE:To make it possible to easily fill a back-filling material having excellent water-permeability through pumping pressure-feed by using a granulated composition made of sand, gravel or granulated substance as mixture of them, thickener and water for backfilling. CONSTITUTION:First of all, a segment 11 is constructed to the inside of a tunnel 10, and injection holes 12 for injecting a backfilling material later are arranged. A wire net having meshes from which sand and gravel contained in the backfilling material are not passed is placed to the end of a backfilled part of a narrow space 14 between a bedrock 13 and the segment 11. While, the backfilling material is made of admixture of aggregate for concrete as a granulated substance, thickener and water After that, the backfilling material is injected into separate narrow spaces 14 partitioned by the wire net 16 through the injection holes 12 by means of a concrete pump. The backfilling material flows smoothly in the narrow space 14, and efficient backfilling and injection can be made. After the filling-up, binder made from the thickener is corroded to flow out, and a backfilled filling layer 20 having required water permeability is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-permeable granular composition used as a water-permeable backing material for the purpose of draining a shield tunnel or the like. It can be suitably used for backfilling and can secure good water permeability.

[0002]

2. Description of the Related Art For example, when constructing a tunnel by a shield construction method, the groundwater level in the ground above the tunnel is lowered to prevent the outflow of groundwater into the tunnel. It is effective to inject a water-permeable backing material. As a conventional backfill material, there is a material prepared by mixing a cement-based filler or a resin with a granular material such as sand, gravel or a mixture thereof to prevent the separation of component materials. Alternatively, a narrow space behind the shield tunnel is filled with a placer. However, this material does not have the function of draining the spring water from the ground because it has a small permeability coefficient, such as cement or resin, as the binder and is kneaded with the granular material.

On the other hand, in the case of a backing material obtained by individually compacting sand, gravel or a granular material made of a mixture thereof without mixing a binder, a water permeability of about 10 ^-2 cm / sec. Is obtained.

[0004]

However, it is impossible to mechanically inject and fill the narrow space on the back surface of the shield tunnel with a backing material composed of only the granular material as described above using a concrete pump or the like. However, even if the backing material was made of only fine sand, it could not be pumped by itself, and there was no means for reliable backfilling other than manual filling. That is, in the conventional backing material, a binder such as cement or resin must be mixed in order to fill the sand / gravel mixture having a large water permeability by pumping, and as a result, the drainage function is lost. On the other hand, if the drainage function is emphasized, there is no choice but to fill the backing material manually, and therefore, in the case of a long-distance drainage tunnel, there is a problem that it is not economically burdened and cannot be practically implemented. ..

Therefore, the present invention has been made in order to solve such a conventional problem, and a pump is prepared by adding an aqueous solution of a thickener to a granular material which is sand, gravel or a mixture thereof. An object of the present invention is to provide a backing material that can be filled by pressure feeding and has excellent water permeability. The present invention also provides
To provide a backing material capable of ensuring excellent water permeability by decomposing the thickening agent with an enzyme to accelerate the decomposition and outflow of the thickening agent after filling, and leaving only granular material as the backing material. With the goal.

[0006]

The first invention of the present application that achieves the above-mentioned object is a water-permeable material used for back-filling which is composed of sand, gravel or a mixture thereof, a granular material, a thickener and water. It is a granular composition. The second invention of the present application is a water-permeable granular composition used for back-filling, comprising a granular material which is sand, gravel or a mixture thereof, a thickener, an enzyme for decomposing the thickener and water. is there.

The thickeners are sodium carboxymethyl cellulose (CMC), methyl cellulose (MC),
It can be at least one selected from the group consisting of sodium hydroxyethyl cellulose (HEC), polyvinyl alcohol (PVA), polyethylene oxide (PEO), polyacrylamide (PAAM), starch and gums.

[0008]

The thickener used in the present invention forms a viscous binder by its aqueous solution to prevent the separation of the particulate matter and to reduce the frictional resistance during pumping.
As a result, the granular material, which cannot be pumped by itself, can be pumped by the pump to efficiently fill the narrow space. The thickener after filling corrodes with the passage of time and flows out from the backing material layer, and only the particulate matter remains and good water permeability is obtained.

However, when an enzyme that decomposes the thickener is added, the decomposition of the thickener after filling is promoted and the water permeability is quickly secured. Hereinafter, the present invention will be described in more detail. The granular material of the present invention is sand alone, gravel alone or a mixture of sand and gravel, and may be generally used as an aggregate of cement concrete. These selections are made according to the water permeability required for the backing material layer after filling.

The thickeners of the present invention are sodium carboxymethyl cellulose (CMC), methyl cellulose (M
C), sodium hydroxyethyl cellulose (HE
C), polyvinyl alcohol (PVA), polyethylene oxide (PEO), polyacrylamide (PAA)
M), starch, gums and the like. It is a natural or synthetic organic polymer compound, and its aqueous solution has viscosity and functions as a binder such as a glue to loosely bond the particles of the above granules to prevent separation and also as a lubricant. It functions and can reduce the frictional resistance during pumping. Each of the above-mentioned group of thickeners can fulfill such a function and can be mutually substituted, and they can be used alone or in combination of two or more kinds.

The water-permeable granular composition of the present invention is intended to be used for backing to construct a water-permeable layer,
(1) Improve the pumpability of granular materials with a thickener and fill the narrow space by pumping. (2) After filling, corrode the thickener used to improve the pumpability to improve water permeability. It recovers. Therefore, the thickener has a property of corroding with the passage of time after filling, resulting in a decrease in viscosity and changing to a state where water easily permeates, that is, the thickener itself corrodes.

It is desirable that the corrosion of the above thickener proceeds as soon as possible after filling. Therefore, the present invention intends that the rate of recovery of water permeability due to corrosion of the thickener can be adjusted as necessary, and (3) a degrading enzyme can be used to promote the corrosion of the thickener. Is.
As the degrading enzyme used in the present invention, a mixture of alkaline cellulase, hemicellulase and pectinase produced by an alkalophilic bacterium can be used. Alternatively, a commercially available powder plant tissue-disintegrating enzyme mainly composed of the above-mentioned three kinds of degrading enzymes derived from Aspergillus niger can be used. Alternatively, when a heteropolysaccharide derived from sap such as gums is used as a thickener, pectetrinase (acting at pH 9.5) produced by Bacillus subnaris can be used.

The water-permeable granular composition of the present invention is prepared by kneading the above-mentioned granular material, water and a thickener, and optionally a decomposing enzyme. As shown in FIG. 1, kneading is performed by using hoppers 1 (granular material), 2 (water), and 2
3 (thickener), 4 (decomposing enzyme) can be put into the kneading container 5 at the same time, whereby particles of the granular material 6 such as sand and gravel are water, thickening agent (and decomposing enzyme). A flowable water-permeable granular composition (that is, backing material) 8 bonded through a binder 7 composed of

Alternatively, it is also possible to knead water, a thickener and a decomposing enzyme in advance to form a viscous binder, and then mix with the granular material. The degrading enzyme is added by an appropriate method, such as by injecting an aqueous solution in which the enzyme is dissolved after filling the backing material with a pump from the top of the shield, instead of performing it when manufacturing the backing material by kneading. It can also be injected.

The following is an example of blending the particulate matter, water, thickener, and degrading enzyme.

[0016]

[Table 1]

[0017]

EXAMPLES Examples of the present invention will be described below. this is,
This is the backfilling work for the purpose of draining water as a countermeasure against spring water from the natural ground. First of all, as shown in FIG.
The segment 11 is built on the inner surface of the tunnel 10 in the same manner as a normal shield tunnel. However, segment 1
1 is provided with an injection hole 12 for injecting the water-permeable granular composition later (in the figure, the granular material particles 6 are shown enlarged with respect to the injection hole 12; The holes 12 are sized so that a large number of the particulate particles 6 can easily pass therethrough). In addition, the ground 13 and the inner structure 1
A wire mesh 16 having a mesh to such an extent that sand and gravel contained in the water-permeable granular composition does not flow out is previously arranged at the end of the backfilled portion of the narrow space 14 with respect to 1 (FIG. 3). reference).

On the other hand, in the container 5 shown in FIG. 1, aggregate for concrete as granular material and CMC as thickener.
And water were kneaded to prepare a water-permeable granular composition (backing material) 8 containing no degrading enzyme (invention product sample 1). An example of the composition is shown in Table 2.

[0019]

[Table 2]

In addition, separately prepared in the same manner as above,
Further, a commercially available powdered plant tissue-disintegrating enzyme was also added as a degrading enzyme and kneaded (invention product sample 2). The backing material of the invention sample 1 and the backing material of the invention sample 2 are
A concrete pump (not shown) was used to inject into the narrow spaces 14 separated by the wire nets 16 from the injection holes 12 as shown in FIG. Each backing material 8 smoothly flowed in the narrow space 14 as indicated by the arrow X in FIG. 4, and efficient backing injection was realized.

On the other hand, the comparative sample in which only the aggregate and water were mixed had an excessive frictional resistance due to the meshing of the particles of the aggregate, and could not be pumped. In the case of the backing material 8 of the invention sample 1 and the invention sample 2, the corrosion of the binder 7 composed of the thickener (and the decomposing enzyme) progresses with the lapse of time after the filling, and the viscosity may decrease to flow out. Admitted.

After the binder 7 has flowed out, a backfill layer 20 having desired water permeability is formed as shown in FIG. In addition, the results of the water permeability test in the room using the invention sample 1 and the invention sample 2 are shown in FIG. As described above, it was confirmed that the water permeability gradually recovers without using the degrading enzyme, but the recovery rate can be remarkably improved by using the degrading enzyme.

FIG. 6 shows the results of the water permeability test when the kind of enzyme in invention sample 2 was changed. Thus, it was confirmed that the recovery rate of water permeability can be changed depending on the type of enzyme.

[0024]

As described above, according to the first aspect of the present invention, the backing material is made of a water-permeable granular composition composed of sand, gravel or a mixture thereof, a thickener and water. Since it is configured, a viscous binder is formed by the aqueous solution of the thickener to prevent the separation of the particulate matter, and it is possible to reduce the friction resistance at the time of pumping the pump.
The effect that pumping is possible and filling can be done efficiently, and that the thickener after filling corrodes with time and flows out from the backing material layer, leaving only particulate matter and obtaining good water permeability. There is.

According to the invention of claim 2, claim 1
In addition to that, because the enzyme that decomposes the thickener was added,
In addition to the same effect as above, promote the decomposition of the thickener,
The effect that a predetermined water permeability can be secured earlier is obtained.

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating preparation of a water-permeable granular composition of the present invention.

FIG. 2 is a vertical cross-sectional view of an example in which the water-permeable granular composition of the present invention is applied to the backfill for draining a shield tunnel.

FIG. 3 is a partial detailed view of the embodiment shown in FIG.

FIG. 4 is a cross-sectional view of essential parts for explaining a state when the backing material is being filled in the embodiment of FIG.

FIG. 5 is a graph showing an example of a water permeability test result of the product of the present invention.

FIG. 6 is a graph showing another example of the results of the water permeability test of the product of the present invention.

[Explanation of symbols]

 6 Particulate particles such as sand and gravel 7 Binder consisting of water and thickener (and decomposing enzyme) 8 Water-permeable granular composition (backing material)

[Procedure amendment]

[Submission date] August 3, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 3

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

The thickeners are sodium carboxymethyl cellulose (CMC), methyl cellulose (MC),
Hydroxyethyl cellulose sodium (HEC), polyvinyl alcohol (PVA), polyethylene oxide (PEO), polyacrylamide (PAAM), hydrin
Roxypropyl methylcellulose (HPMC), hydro
It can be at least one selected from the group consisting of xyethylmethyl cellulose (HEMC), starch, gums and the like.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

The thickeners of the present invention are sodium carboxymethyl cellulose (CMC), methyl cellulose (M
C), sodium hydroxyethyl cellulose (HE
C), polyvinyl alcohol (PVA), polyethylene oxide (PEO), polyacrylamide (PAA)
M), hydroxypropyl methylcellulose (HPM
C), hydroxyethyl methylcellulose (HEM
C), starch, gums and the like. It is a natural or synthetic organic polymer compound, and its aqueous solution has viscosity and functions as a binder such as a glue to loosely bond the particles of the above granules to prevent separation and also as a lubricant. It functions and can reduce the frictional resistance during pumping. Each of the above-mentioned group of thickeners can fulfill such a function and can be mutually substituted, and they can be used alone or in combination of two or more kinds.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Toru Sueoka 1-25-1 Nishishinjuku, Shinjuku-ku, Tokyo Within Taisei Corporation (72) Inventor Yasuko Shinmura 1-25-1 Nishishinjuku, Shinjuku-ku, Tokyo (72) Inventor Minoru Fujita 8-6-5 Hamakaze-cho Ashiya-shi, Hyogo Prefecture (72) Inventor Kiyomi Ishibashi 7-7-33 Takamaru, Tarumi-ku, Kobe-shi, Hyogo Prefecture

Claims (3)

[Claims] 1. A water-permeable granular composition for back-filling, comprising a granular material which is sand, gravel or a mixture thereof, a thickener and water. 2. A water-permeable granular composition used for back-filling, which comprises sand, gravel or a mixture thereof, a thickener, an enzyme for decomposing the thickener and water. 3. The thickener is sodium carboxymethyl cellulose (CMC), methyl cellulose (M
C), sodium hydroxyethyl cellulose (HE
C), polyvinyl alcohol (PVA), polyethylene oxide (PEO), polyacrylamide (PAA)
The water-permeable granular composition for backfilling according to claim 1 or 2, which is at least one member selected from the group consisting of M), starch, gums and the like.