JPH10102485A - Method of forming permeable layer section to soil-cement diaphragm wall - Google Patents

Abstract

PROBLEM TO BE SOLVED: To flow groundwater by forming a permeable layer section to soil- cement diaphragm walls on both sides of an underground structure after the building of the underground structure at the time of the construction of the underground structure. SOLUTION: The soil-cement diaphragm walls 1, 1, in which core materials consisting of H-steel are buried, are constructed on both sides of underground structures to be built 6 at regular intervals, and the underground structures 6 are erected under the state that the water courses 7 of groundwater are interrupted once by these soil-cement diaphragm walls 1, 1. In the wall body sections of the soil-cement diaphragm walls 1, to which permeable layer sections 3a, 3b must be formed beforehand, after construction, permeable ground layers 7a installed into a ground, into which the underground structures 6 are buried, and the permeable layer sections 3a, 3b communicating with the water courses 7 of groundwater are formed by crushing wall body sections by crushers while guiding the crushers by guide members beforehand annexed to the opposed surfaces of the adjacent core materials.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underground structure such as a subway which is constructed by constructing an underground soil cement wall along the outside of the planned underground structure. The present invention relates to a method of blocking the flow of groundwater during construction of an object, and forming a permeable layer portion for securing a free flow of groundwater on the underground wall of the soil cement after the construction of the underground structure.

[0002]

2. Description of the Related Art Conventionally, when constructing an underground structure underground such as subway construction, an underground structure to be built, that is, a soil retaining wall along both outer wall surfaces of a planned underground structure. After that, an underground structure is being built between the retaining walls. At this time, as a method of constructing the earth retaining wall, an SMW that is highly water-proof, has a short construction time, and is economical
(Soil miximg wall) The construction method is adopted. According to this method, as shown in FIG. 13, a plurality of holes A which are continuous with each other are formed in a ground where an earth retaining wall is to be formed by an excavator capable of simultaneously excavating and stirring earth and sand to a certain depth. The cement milk and the earth and sand are stirred and mixed into a slurry by injecting the cement milk into the holes A according to the drilling, and H is introduced into each hole A before the slurry hardens.
The retaining wall consisting of the soil cement underground wall is constructed by embedding the shape steel B and hardening the slurry.

When such a retaining wall is constructed, the flow of groundwater is blocked by the retaining wall, and the water level rises upstream of the groundwater with the retaining wall interposed therebetween, thereby causing flooding and overflow of well water. On the other hand, problems such as well withering occur on the downstream side. Therefore, when the construction work of the underground structure is completed, a part of the earth retaining wall is crushed by a crusher until it reaches the groundwater flow path, and a water permeable portion is formed on the earth retaining wall.

[0004]

However, since the H-section steel is buried at regular intervals in the retaining wall, a crushing bit is required when the crushing machine crushes the retaining wall portion between the H-sections. May come into contact with the H-section steel and break, making it impossible to break the retaining wall. For this reason, after extracting the H-section steel, the crushing machine may be used to crush the retaining wall, but the H-section steel has an extremely high adhesive force to the soil cement, and it takes a great deal of cost and time to extract it. In addition, when the depth of the retaining wall is large, there is a case where the drawing cannot be performed.

[0005] Further, in the case where groundwater flow paths exist above and below the water-impermeable stratum in the ground, if the soil retaining wall is crushed to form a water-permeable layer as described above, As a result, the upper and lower underground waterways communicate with each other, and there is a possibility that the flow of the underground water changes and causes destruction of the natural environment. The present invention has been made in view of such problems, and its purpose is to form a permeable layer portion on a soil cement underground wall constructed along the outer wall of the planned underground structure, The H-shaped steel buried in the underground wall is not pulled out and the crusher bit is prevented from being damaged by the H-shaped steel, and a permeable layer part is formed reliably and efficiently at the part communicating with the underground waterway. There is a way in which you can do it.

[0006]

In order to achieve the above object, the present invention provides a method for forming a permeable layer on an underground soil cement wall constructed along the outer wall of a planned underground structure, comprising the steps of: In the core material made of steel buried at regular intervals during the construction of the middle wall, a guide member is previously integrated with the facing surface of the facing core material in the wall portion of the soil cement ground wall where the permeable layer is to be formed. After the construction of the soil cement underground wall, these guide members are used as guides to crush the wall portion between the guide members by a crusher to form a permeable layer portion communicating with the underground waterway. It is characterized by the following.

According to a second aspect of the present invention, the soil cement underground wall is constructed along both outer walls of the planned underground structure,
After constructing an underground structure in the ground between these soil cement ground walls, crush the wall portion between the guide members on the soil cement ground walls on both sides sandwiching the underground structure with a crusher. It is characterized by forming a water-permeable layer portion that is continuous to allow water to flow.

Further, the invention according to claim 3 is a method for forming a water-permeable layer on an underground wall of a soil cement according to claim 1 or 2, wherein the underwater structure is embedded in an impermeable ground layer. Forming a water-permeable ground layer continuous with the upper and lower sides of the soil cement ground wall on both sides facing the upper and lower sides, and crushing the wall body between the guide members on the soil cement ground wall on both sides by a crusher. When forming the permeable layer portion, the permeable layer portion is formed at a height portion communicating with the permeable ground layer, and the other portions are formed in the impermeable layer portion by injecting and hardening cement milk. It is assumed that.

[0009]

According to the first aspect of the present invention, the guide member is integrally provided in advance on the opposing surface of the opposing core material in the wall portion of the soil cement ground wall where the water permeable layer is to be formed. As a result, the wall portion between the guide members is efficiently crushed to a desired depth while guiding the crusher along the guide members and preventing the digging bits of the crusher from contacting the core material by the guide members. By this crushing, a permeable layer portion of the groundwater that has been blocked up to then can be easily formed on a part of the soil cement underground wall.

According to the second aspect of the present invention, the wall portion between the core members of the soil cement underground wall constructed so as to sandwich the planned underground structure is crushed by the crusher after the underground structure is built. Since the permeable layer is formed by crushing the guide member as a guide as described above, the groundwater flow can be shut off by the soil cement underground walls on both sides until the underground structure is constructed. After construction of the underground structure, groundwater flows from the permeable layer of the soil cement ground wall to the permeable layer of the other soil cement ground wall through the permeable ground layer in the ground where the underground structure is buried. Can be distributed.

Further, according to the third aspect of the present invention, a permeable ground layer is formed in the upper and lower portions of the impermeable ground layer in which the underground structure is buried, and communicates with the upper and lower permeable ground layers. Since the permeable layer is formed on the upper and lower walls of the soil cement underground wall on both sides, the groundwater flow path exists above and below the impermeable ground layer under the ground. Without connecting the upper and lower groundwater flow paths to each other, the original flow before the underground structure was built through the upper and lower permeable layers of the soil cement ground wall and the buried ground of the buried ground of the underground structure, respectively. It can be distributed in a state, so that there is no danger of changing the natural environment.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows that when an underground structure such as a subway is constructed, the underground structure is taken from the ground along the outer wall of the underground structure. FIG. 1 is a partial plan view of a soil cement underground wall 1 serving as a retaining wall constructed to a depth deeper than a structure, the soil cement underground wall 1 being a mixture of solidified soil and cement milk. The core material 2 made of H-shaped steel is buried at regular intervals in the length direction in the wall body thus formed,
The permeable layer 3 is provided in a part thereof. This permeable layer part 3
Of the soil cement ground wall 1 between the guide members 4, 4 made of a steel strip integrated with the core members 2, 2 attached to the opposing surfaces of the adjacent core members 2, 2 over the entire length. It is formed by crushing the wall portion 1a.

In order to form the above-described permeable layer portion 3 on a part of the soil cement underground wall 1, at the time of constructing the soil cement underground wall 1, a soil cement layer on which the permeable layer portion 3 is to be formed in advance. Opposing core members 2, 2 in the wall portion 1 a of the middle wall 1
The above-mentioned guide member 4 is integrally attached to the opposing surface, and after the soil cement underground wall 1 is constructed, the guide member 4 is guided by these guide members 4, 4 as shown in FIG. It is formed by crushing the wall portion 1a between 4, 4 by the crusher 5. That is, the water permeable layer 3 is formed by the gap formed between the crushed pieces of the wall 1a crushed by the crusher 5 to allow water to flow.

As shown in FIG. 3, the soil cement underground wall 1 is provided along both outer walls 6a, 6a of the underground structure 6 to be built. With the flow path 7 temporarily blocked, an underground structure 6 is built in the ground between the soil cement ground walls 1 and 1 and then communicates with the ground water flow path 7 on the soil cement ground walls 1 and 1. Forming the permeable layer part 3 to break the groundwater, and circulate the water from the upstream side to the downstream side through the permeable buried sediment of the underground structure 6. The work procedure up to building will be described in detail.

First, the underground structure 6 to be built, that is, a slot which is slightly wider than the width of the planned underground structure so as to sandwich the planned underground structure and deeper than the bottom surface of the planned underground structure 8, 8 are excavated along both outer walls of the planned underground structure, and according to the excavation, the slots 8, 8 are made of a mixture of cement milk and earth and sand, and are arranged at regular intervals in the longitudinal direction of the planned underground structure. A soil cement underground wall 1 in which a core material 2 made of H-section steel is embedded is constructed.

The excavation of the slot 8 is performed as shown in FIG.
This is performed using a drilling machine 9 that supports a screw auger 9b on a carriage 9a so that the screw auger 9b can be rotated and moved up and down, and by rotating the screw auger 9b downward while rotating, the circular groove reaching a predetermined depth from the ground surface. After excavating the hole 8a and excavating the groove 8a, the next groove 8a is excavated so as to partially overlap the groove 8a, and thus the groove 8a which is continuous with each other is formed. The excavation is performed sequentially and continuously along both outer walls of the planned underground structure to form the slots 8. At this time, after excavating the slots 8a at regular intervals, the slots 8a that connect the slots 8a may be excavated.

As a method for constructing the soil cement underground wall 1 serving as a retaining wall in the slot 8, the above-described SMW (soil m
iximg wall) The construction method is adopted. That is, when excavating the slot 8a by the screw auger 9b, by injecting cement milk from the tip of the screw auger 9b through the hollow interior of the screw auger 9b, the earth and sand excavated by the screw auger 9b and the cement Milk is stirred and mixed to form a slurry, and before this slurry is hardened, as shown in FIG. 5, a core material 2 made of H-shaped steel is built in each slot 8a and the slurry is hardened. An impervious soil cement underground wall 1 in which cores 2 are embedded at regular intervals in the length direction is constructed.

When the core material 2 is sequentially built into each of the slots 8a, the slots 8a sandwiching the portion where the water-permeable layer 3 is to be formed,
The core members 2 and 2 having the guide members 4 and 4 provided integrally on the opposing surface are built in 8a. The guide member 4 is a crusher 5
As shown in FIG. 6, the crushing bit 5a of the crusher 5 also serves to prevent the crushing bit 5a of the crusher 5 from being damaged by hitting the end of the flange 2a of the core material 2.
Flanges at both ends in the width direction of soil cement underground wall 1
In the case of the core material 2 having 2a, 2a, the flange portions 2a, 2a
A guide member 4 made of a steel strip wider than the width between the flanges 2a is provided along the entire length of the core 2 so as to extend between the end faces of the flanges 2a and 2a, and the rear side of the core member 2 is provided with the flanges 2a and 2a. It is fixed to the end face by welding or the like, or as shown in FIG.
As shown in the figure, a steel guide member 4a, which is bent in an arc shape in cross section, is provided on the ends of the opposed flange portions 2a, 2a of the core members 2, 2, with the convex arc surfaces facing each other. To be fixed.

The core member 2 with a guide member shown in FIGS. 6 and 7 is erected at the center of the adjacent slots 8a, 8a, respectively, as shown in FIGS. Member 4
Core made of H-section steel narrower than core 2 not provided with
2 ′, the guide member 4 or
4a may be attached integrally, and the core 2 'may be deflected toward the core 2 on which the guide member 4 is not provided and may be built in the slot 8a. Core material
2 ', 2' interval can a widely between, therefore, it is possible to form the width L ₁ is large aquifer unit 3 in subsequent.

As shown in FIG. 10, the core 2 'may be built with the flanges 2a, 2a facing the length direction of the soil cement ground wall 1 in this case. Is
The crusher 5 can be guided vertically by the flat surfaces of the opposed flange portions 2a, 2a.
Although the guide members 2a and 2a can be used as the guide member 4, in this case as well, it is desirable to attach the auxiliary guide member 4b to the ends of the flange portions 2a and 2a.

As described above, the soil cement underground walls 1, 1 in which the core members 2, 2 with the guide members are embedded at regular intervals in the wall portion where the water permeable layer portion 3 is to be formed are connected to the planned underground structure. When constructed underground along both outer walls, the flow path 7 of the groundwater which had been circulating until the formation of the permeable layer 3 between the guide members 4, 4 causes these soil cement underground walls 1, 1. In this state, the ground between the soil cement underground walls 1 and 1 is excavated to construct the underground structure 6.

The construction method of the underground structure 6 is as follows.
As shown in FIG. 11, a space portion 11 is provided by excavating and excluding the ground between both soil cement ground walls 1 and 1 using a drilling tool 10 such as a bucket. At this time, the soil between the soil cement underground walls 1 and 1 has a water-permeable ground layer forming a flow path 7 through which groundwater flows before the soil cement underground walls 1 are constructed. 7a and an impermeable ground layer 12 that does not allow groundwater to flow exist. These ground layers 7a and 12 are excavated and removed by the excavator 10 as described above. Note that FIGS. 3 and 11 show a case where there are upper and lower flow paths made of a water-permeable ground layer above and below the ground via the water-impermeable ground layer 12 as the groundwater flow path 7.

The underground structure 6 is built in the space 11 excavated and eliminated as described above. First, the permeable material such as gravel is placed on the impermeable ground layer 12 ′ supporting the bottom wall 6 b of the underground structure 6. After forming the lower permeable ground layer 7b by backfilling the soil and sand, the underground structure 6 is built on the lower permeable ground layer 7b.
(See FIG. 3). In parallel with the construction of the side walls 6a, 6a of the underground structure 6, or after the construction of the side walls 6a, 6a, the lower end portions of the outer walls of the side walls 6a, 6a and the both side soil cement grounds facing the lower end portions. A permeable ground layer 7b 'connected to the permeable ground layer 7b is formed between the lower ends of the middle walls 1 and 1 by backfilling sand and gravel in the same manner as described above.

Further, the upper end portions of the side walls 6a, 6a are placed in the space between the opposing surfaces of the side walls 6a, 6a of the underground structure 6 and the soil cement ground walls 1, 1 from above the permeable ground layer 7b '. After the impermeable ground layer 12a reaching the vicinity is formed by backfilling the impermeable soil, the upper permeable ground layer 7a is backfilled with sand and gravel on the ceiling wall 6c of the underground structure 6 in the same manner as described above. Between the upper ends of the outer walls of the side walls 6a, 6a and the upper ends of the soil cement ground walls 1, 1 opposed to the upper ends, the permeable ground connected to both ends of the upper permeable ground layer 7a. The layer 7a 'is formed by backfilling sand and gravel in the same manner as described above, and the water-impermeable soil layer is backfilled from the water-permeable ground layers 7a, 7a' to the space between the ground surfaces to form the water-impermeable ground layer 12b. To form.

After the construction and burial of the underground structure 6, as described above, the wall 1a between the core members 2 with the guide members in the soil cement underground walls 1 and 1 on both sides as shown in FIG. ,
The crusher 5 is lowered while being guided by the guide members 4, 4 and crushed by the rotary crushing bit 5 a to form the permeable layer portion 3 communicating with the underground structure 6 side and the outside of the underground structure 6. . The crusher 5 is provided with an auger screw 5c and a stirring blade 5d integrally below the rotating shaft 5b, and has a disk portion 5e provided with a plurality of crushing bits 5a protruding downward at the lower end. It has a structure in which a rotary shaft 5b at an intermediate portion of the auger screw 5c is provided with an outlet 5f for cement milk supplied from the ground side through the hollow interior of the rotary shaft 5b.

In order to form the water permeable layer 3 by using the crusher 5, first, the crusher 5 crushes the wall 1a between the guide members 4 and 4 until it reaches the vicinity of the lower end. Body
The part where the lower end of 1a is left without crushing is shown in FIG.
After the lower impervious layer 13 is formed, the crusher 5 is pulled up by a certain length, and the portion facing the lower permeable ground layer 7b is exposed to the lower permeable layer formed of the crushed pieces of the wall 1a. While the crushing machine 5 is being lifted, cement milk is poured from the lower end of the crushing machine 5 into the portion facing the impermeable ground layer 12a to eliminate the gap between the crushed pieces and crush the portion. After forming the intermediate water-impermeable layer portion 14 by integrally fixing the pieces together, the portion facing the upper water-permeable ground layer 7a is defined as an upper water-permeable layer portion 3a made of crushed pieces of the wall portion 1a. A portion reaching the surface from the permeable layer portion 3a is formed in the upper impermeable layer portion 15 by injecting cement milk while lifting the excavator 5.

When the upper and lower permeable layers 3a and 3b are formed between the core members 2 and 2 with the guide members as described above, the flow path 7 of the upper and lower groundwater,
7 is a soil cement underground constructed on the downstream side through the permeable ground layers 7a and 7b provided on the upper and lower sides of the underground structure 6 from the upper and lower permeable layers 3a and 3b of the soil cement underground wall 1 constructed on the upstream side. Groundwater can be circulated from the upper and lower permeable layers 3a and 3b of the wall 1 to the original upper and lower groundwater flow paths 7a and 7b, respectively. At this time, the intermediate water-impermeable layer 14 and the water-impermeable ground layer 12a are provided between the upper and lower water-permeable layers 3a and 3b and between the upper and lower water-permeable ground layers 7a and 7b, respectively. The groundwater passages 7a and 7b do not communicate with each other, and therefore can be separately supplied as before the underground structure 6 is constructed.

When the permeable layers 3a and 3b are formed on the soil cement underground wall 1 by the crusher 5, the soil cement underground wall 1 is used when the soil and the cement are mixed with the cement milk during the construction. Part of the cement milk is in the slot
Since it is in a state of penetrating into the outside ground side from 8a, FIG.
As shown in FIG. 10, the soil cement underground wall 1 is crushed wider by the crusher 5 than the width of the slot 8a so as to cover even the infiltration region.

When forming the water permeable layer 3 of the soil cement ground wall 1, the water permeable ground layers 7a and 7b are present above and below the ground through the water impermeable ground layer 12 as described above. In this case, the upper and lower permeable layers 3a and 3b communicating with the permeable ground layers 7a and 7b are formed through the intermediate impervious layer 14, respectively. If there is only one road 7, the underground structure 6
In the buried ground, a layer of water-permeable ground is formed so as to be continuous with the flow path 7, while the wall portion 1 a of the soil cement ground wall 1 is provided with the flow path 7 of the groundwater and the underground structure. What is necessary is just to form the permeable layer part 3 communicating with the permeable ground layer in the ground where the object 6 is buried.

In this case, the wall 1a between the guide members 4, 4 fixed to the opposing surfaces of the core members 2, 2 of the soil cement underground wall 1 is crushed by the crusher 5 over the entire height. After the permeable layer portion 3 is formed, only the upper end on the ground surface is made to be an impermeable layer portion, or only the portion of the groundwater flow path 7 that communicates with the permeable ground layer in the buried ground of the underground structure 6 is removed. A method of forming the permeable layer portion 3 can be adopted.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a soil cement underground wall provided with a permeable layer portion,

FIG. 2 is a vertical cross-sectional side view showing a state in which a permeable layer portion is formed.

FIG. 3 is a longitudinal sectional front view showing a state in which soil cement underground walls are constructed on both sides of an underground structure.

FIG. 4 is a simplified front view of a state where a slot is being excavated;

FIG. 5 is a simplified front view of a state in which a core material is erected.

FIG. 6 is a cross-sectional view of a wall portion between core materials forming a permeable layer portion;

FIG. 7 is a cross-sectional view of a wall portion between core materials provided with guide members of different shapes,

FIG. 8 is a cross-sectional view showing a wall portion between core materials when a wide permeable layer portion is formed;

FIG. 9 is a cross-sectional view showing a modified example thereof,

FIG. 10 is a cross-sectional view showing still another modification.

FIG. 11 is a simplified vertical sectional front view showing a state where the ground between soil cement ground walls is excavated;

FIG. 12 is a simplified vertical sectional front view showing a state in which a permeable layer portion is formed on both sides of an underground structure.

FIG. 13 is a cross-sectional view of a retaining wall for explaining a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Underground wall of soil cement 2 Core material 3, 3a, 3b Permeable layer 4 Guide member 5 Crusher 6 Underground structure 7 Groundwater flow path 7a, 7b Permeable ground layer 12 Impermeable ground layer

Claims (3)

[Claims] 1. A method of forming a permeable layer portion on an underground soil cement wall constructed along an outer wall of a planned underground structure, wherein the permeable layer portion is buried at regular intervals when the underground soil cement wall is constructed. In a core material made of steel, a guide member is integrally provided in advance on an opposing surface of the opposing core material in the wall portion of the soil cement ground wall where the water permeable layer is to be formed, and the soil cement ground wall is After the construction of the above, the wall portion between the guide members is crushed by a crusher using these guide members as a guide to form a permeable layer portion communicating with the underground waterway. How to form the part. 2. The underground soil cement wall is constructed along the outer walls on both sides of the planned underground structure, and after the underground structure is built in the ground between these soil cement underground walls, the underground structure is sandwiched. 2. The soil cement according to claim 1, wherein a wall portion between the guide members is crushed by a crusher on the soil cement underground walls on both sides to form a continuous permeable layer portion allowing water to pass through each other. A method of forming a permeable layer on an underground wall. 3. A soil-permeable ground layer formed on the upper and lower sides of an impermeable ground layer in which an underground structure is buried, and a water-permeable ground layer continuous with upper and lower portions of opposing surfaces of the soil cement ground walls on both sides. When the wall portion between the guide members is crushed by a crusher to form a permeable layer portion, the permeable layer portion is formed at a height portion communicating with the permeable ground layer, and the other portions are cemented. 3. The method for forming a water-permeable layer on an underground soil cement wall according to claim 1 or 2, wherein the water-permeable layer is formed on the impermeable layer by injecting and hardening milk.