JP2017214798A - Construction method of underground continuous wall and underground continuous wall - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a construction method or the like of an underground continuous wall which allows easy ground excavation and skeleton construction at the construction of an underground structure.SOLUTION: Concrete 31 is placed into an excavation groove 20 formed at the ground by inserting a reinforced cage 100a into the excavation groove, and a preceding element 301a of an underground continuous wall is constructed. After that, a reinforced cage 200 is inserted into an excavation groove formed at a sideway of the preceding element 301, the concrete 31 is placed therein, a succeeding element 302 of the underground continuous wall is constructed, thus constructing the underground continuous wall so that a lower end reaches a depth exceeding a water non-permeable layer of the ground. At this time, a block part 23 is formed by injecting an injection material into a clearance 22 of a corner part of the preceding element 301 of the underground continuous wall at a depth reaching at least the water non-permeable layer by using an injection pipe 120 which is arranged in the vicinity of the corner part of the reinforced cage 100a. By this constitution, it is prevented that water leakage occurs due to the clearance 22 which becomes a water passage in a vertical direction, and hindrance occurs at the ground excavation and the skeleton construction at the construction of an underground structure.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an underground continuous wall construction method and an underground continuous wall.

  There is an underground tank as a facility for storing low-temperature liquefied gas such as LNG (liquefied natural gas) and LPG (liquefied petroleum gas). FIG. 12 shows an outline of the underground tank 10. The underground tank 10 is an underground structure in which a skeleton is constructed by excavating an internal ground using a substantially cylindrical underground continuous wall 30 made of reinforced concrete as a mountain retaining and impermeable wall.

  The housing of the underground tank 10 is generally composed of a slab-made bottom slab 11 and side walls 12 and a steel roof 13. The side wall 12 is formed in a substantially cylindrical shape on the bottom plate 11, and a heat insulating material, a membrane (not shown), and the like are installed on the inner surfaces of the bottom plate 11 and the side wall 12.

  In order to perform excavation and frame construction inside the underground continuous wall 30 in a dry state, the lower end of the underground continuous wall 30 is planned to reach a depth exceeding the impermeable layer 21 (referred to as a vertical position). It is common to be done. Since the underground tank 10 is constructed to a depth of 40 to 50 m, the underground continuous wall 30 is required to withstand large earth pressure and water pressure, and its scale becomes large.

  When the underground continuous wall 30 is constructed, first, excavation grooves are formed in the ground at predetermined intervals in the circumferential direction of the underground continuous wall 30, and the preceding element of the underground continuous wall 30 is constructed in the excavation groove. Thereafter, a digging groove is formed between the preceding element and the trailing element of the underground continuous wall 30 is constructed in the digging groove (for example, Patent Documents 1 and 2).

  FIG. 13 shows a construction method of the underground continuous wall 30. In this example, when constructing the preceding element, the ground is first excavated into a strip shape by a continuous wall excavator or the like to form the excavation groove 20 as shown in FIG. 100 is inserted.

  FIG. 14 is a view showing the reinforcing bar 100. The reinforcing bar 100 has vertical and horizontal reinforcing bars 101 and 102, and a bonded steel plate joint is provided at both ends of the reinforcing bar 100 as one of the connecting structure of the adjacent preceding element and the succeeding element.

  In the following description, the term “width” of the reinforcing bar rod refers to the length of the underground continuous wall 30 in the radial direction, and in FIG. 14, the length in the short side direction (vertical direction in the figure) of the plane of the reinforcing rod rod 100. Corresponds to. Similarly, the “length” of the reinforcing bar rod refers to the length in the circumferential direction of the underground continuous wall 30, and in FIG. 14, the length in the long side direction (left-right direction in the drawing) of the plane of the reinforcing rod rod 100. Corresponds to. The same applies to the width and length of the excavation groove. The bar part of the reinforcing bar corresponds to the lengthwise end of the reinforcing bar bar. Further, the outer side of the reinforcing bar rod means the one far from the plane center of the reinforcing bar rod, and the opposite is the inner side.

  The bonded steel plate joint is configured by providing a steel plate 111 as a partition plate at the end portion of the reinforcing bar 100 and attaching a civil engineering sheet 112 and a presser plate 113 to the steel plate 111 in the vicinity of the corner of the flat surface of the reinforcing bar 100. The reinforcing bar 100 has a width and length slightly smaller than the width and length of the excavation groove 20 so that it can be inserted into the excavation groove 20. The civil engineering sheet 112 is disposed in the length direction of the reinforcing bar 100 with both ends attached to the steel plates 111 of both ends of the reinforcing bar 100. The holding plate 113 is, for example, an iron plate or a hard rubber sheet, and is disposed in the length direction of the reinforcing bar 100 on the outside of the civil engineering sheet 112. In addition, the reinforcing bar 100 is also provided with a tie rod 103 that connects the steel plates 111 at both ends.

  After inserting the reinforcing bar 100 into the excavation groove 20, the leading element 301 is constructed as shown in FIG. 13B by placing and filling concrete into the excavation groove 20. The concrete 31 is placed between the civil engineering sheets 112 on both sides in the width direction of the reinforcing bar 100, and the concrete 31 is prevented from flowing out to the trailing element side by the steel plate 111, the civil engineering sheet 112, and the holding plate 113 of the joined steel plate joint. Is done.

  The civil engineering sheet 112 bulges outward due to the placement pressure of the concrete 31 and the presser plate 113 is deformed accordingly. Eventually, the end of the presser plate 113 comes into contact with the inner wall of the excavation groove 20, and the civil engineering sheet 112. Is prevented from overhanging the trailing element side and being damaged. The tie rod 103 prevents the steel plate 111 from being damaged by the casting pressure of the concrete 31.

  After placing the concrete 31 of the preceding element 301, as shown in FIG. 13 (c), the ground on the side is excavated in the same manner as described above to form the excavation groove 20, and as shown in FIG. 13 (d). When the reinforcing bar 200 is inserted into the excavation groove 20 and the concrete 31 is placed therearound, the trailing element 302 is constructed.

JP 63-35915 A Japanese Patent Laid-Open No. 2002-13135

  In FIG. 13B and the like, for convenience of explanation, the interval between the inner wall of the excavation groove 20 and the side end portion of the steel plate 111 is shown wide, but actually the side end portion is close to the inner wall of the excavation groove 20. Has reached. Therefore, as shown in FIG. 13D, when the concrete 31 of the succeeding element 302 is placed, the concrete 31 does not go around to the outside of the presser plate 113, and is near the connecting portion between the preceding element 301 and the succeeding element 302. In many cases, a substantially triangular gap 22 remains at the corner of the preceding element 301. The gap 22 is formed over the entire depth of the underground continuous wall 30 as shown in FIG.

  Thus, when the corner of the preceding element 301 remains as the gap 22, even if the lower end of the underground continuous wall 30 reaches a depth exceeding the impermeable layer 21, the gap 22 becomes a vertical water supply. As a result, water leakage may occur, which may hinder excavation of the underground continuous wall 30 and the construction of the frame.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for constructing an underground continuous wall that enables easy excavation and building of a structure during construction of an underground structure. .

  1st invention for solving the subject mentioned above inserts the rebar rod which provided the partition plate in the excavation groove of the ground, and lays concrete, and constructs the preceding element of the underground continuous wall The process and the step of constructing the downstream element of the underground continuous wall by placing concrete in the excavation groove on the side of the preceding element so that the lower end reaches a depth exceeding the impermeable layer of the ground. When constructing a continuous wall, and when constructing the underground continuous wall, at the depth corresponding to the impermeable layer, the corner of the preceding element located in the vicinity of the connecting portion of the preceding element and the succeeding element, It is the construction method of the underground continuous wall characterized by using a closing jig provided in advance near the corner of the reinforcing bar of the preceding element.

  According to the present invention, at the depth corresponding to the water-impermeable layer of the underground continuous wall, the corner of the preceding element is filled to be a closed portion, and it is possible to prevent water leakage using the gap as a water supply. It will be possible to easily excavate the ground and build the frame during construction. At this time, by using a closing jig provided in the vicinity of the corner of the reinforcing bar in advance, the corner can be surely filled without trouble.

The underground continuous wall is provided in a cylindrical shape at a position surrounding the underground structure, and only the corner of the preceding element on the underground structure side is filled with the closing jig.
In the present invention, it is only necessary to fill the corners on the underground structure side of the preceding element, and the corners on the ground side need not be filled, so the work is simplified.

The closing jig is an injection tube having an injection hole for injecting an injection material into a corner of the preceding element, and injecting the injection material into the corner from the injection tube to fill the corner. Is desirable. Further, it is desirable that a cover having a slit is provided so as to cover the injection hole.
Thus, by injecting the injection material using the injection pipe attached in advance to the reinforcing bar rod, the corner of the preceding element can be filled easily, and the injection pipe is inserted into the gap by boring later. There is no need to secure space. Further, by providing a cover with a slit around the injection hole, the injection material can be injected while preventing the inflow of earth and sand into the injection tube, the back flow of the injection material, and the like.

When injecting an injection material into the corner of the preceding element, an inner tube having a hole and having a bag body provided above and below the hole is inserted into the injection tube, and the upper and lower bag bodies are expanded to expand the bag. It is desirable that the injection material delivered from the hole of the inner tube is in close contact with the inner wall of the injection tube and injected from the injection hole into the corner of the preceding element.
In this way, by inserting the inner tube into the injection tube and injecting the injection material from the inner tube in a state where the bag body above and below the hole of the inner tube is inflated and in close contact with the inner wall of the injection tube, There is no escape up and down, and reliable injection can be performed at high pressure.

The closing jig is a bag body, and it is desirable that the bag body is filled with a filler to fill the corners of the preceding element.
Thus, the corner of the preceding element can be easily filled by filling the bag with the filler.

In the vicinity of the corner of the reinforcing bar rod, a sheet in the length direction of the reinforcing bar rod and a pressing plate outside the sheet are attached to the partition plate, and the bag body may be provided outside the pressing plate. desirable.
Thereby, the substantially triangular gap outside the presser plate generated when the concrete of the preceding element is placed can be filled by filling the bag.

Further, the closing jig is a movable portion provided near the corner of the reinforcing bar, and when the concrete of the preceding element is placed, the movable portion substantially contacts the inner wall of the excavation groove, It is also desirable that the corner of the preceding element is filled with the concrete inside the movable part.
In this way, when the preceding element is placed in concrete, the movable portion moves and substantially contacts the inner wall of the excavation groove, so that the corner of the preceding element inside the movable portion can be filled with concrete.

For example, the movable part is a slide member attached to the partition plate and slidable in the width direction of the reinforcing bar rod, and a sheet in the length direction of the reinforcing bar rod is attached to the slide member.
Alternatively, the movable part is a rotating member that is attached to the partition plate and is rotatable toward the inner wall of the excavation groove, and a sheet in the length direction of the reinforcing bar is attached to the rotating member.
As described above, as the movable portion, a slide member or a rotary member that moves together with the civil engineering sheet or the like in accordance with the concrete placement of the preceding element can be used, whereby the corner portion of the preceding element can be suitably filled.

A second aspect of the present invention is an underground continuous wall having a plurality of adjacent elements constructed in a ground excavation groove, the lower end of the underground continuous wall reaching a depth exceeding the impermeable layer of the ground, The element is constructed by embedding a reinforcing bar with a partition plate in the end portion of concrete filled in the excavation groove of the ground, and the other element is formed in the excavation groove on the side of the one element. The corner of the one element located in the vicinity of the connecting portion between the two elements is buried at a depth corresponding to the impermeable layer and is filled with concrete, and the corner of the reinforcing bar of the one element An underground continuous wall characterized in that a closing jig for filling a corner of the one element is provided in the vicinity of the portion.
The underground continuous wall is provided in a cylindrical shape at a position surrounding the underground structure, and only the corner of the one element on the underground structure side is filled.

  The closing jig is an injection tube having an injection hole for injecting an injection material into a corner of the one element, and the corner is preferably filled with the injection material. It is also desirable that a cover having a slit is provided so as to cover the injection hole.

  Alternatively, the closing jig may be a bag body, and a corner portion of the one element may be filled with the bag body filled with a filler. For example, in the vicinity of the corner of the reinforcing bar rod, a sheet in the longitudinal direction of the reinforcing bar rod and a pressing plate outside the sheet are attached to the partition plate, and the bag body is provided on the outer side of the pressing plate.

  Furthermore, the movable part, which is the closing jig provided near the corner of the reinforcing bar, substantially abuts against the inner wall of the excavation groove, and the concrete of the one element on the inner side of the movable part The corners of the element may be filled.

For example, the movable part is a slide member attached to the partition plate and slidable in the width direction of the reinforcing bar rod, and a sheet in the length direction of the reinforcing bar rod is attached to the slide member.
Alternatively, the movable part is a rotating member that is attached to the partition plate and is rotatable toward the inner wall of the excavation groove, and a sheet in the length direction of the reinforcing bar is attached to the rotating member.

  According to the present invention, it is possible to provide a method for constructing an underground continuous wall and the like that can easily perform ground excavation and frame construction during construction of an underground structure.

The figure which shows the underground continuous wall 30a typically The figure which shows the reinforcing bar rod 100a, the injection tube 120, etc. The figure explaining the construction method of underground underground wall 30a The figure which shows the reinforcing bar rod 100b The figure explaining the construction method of underground underground wall 30a The figure which shows the reinforcing bar rod 100c The figure explaining the construction method of underground underground wall 30a The figure which shows the reinforcing bar rod 100d The figure explaining the construction method of underground underground wall 30a The figure which shows the reinforcing bar rod 100e The figure explaining the construction method of underground underground wall 30a The figure which shows the underground tank 10 and the underground continuous wall 30 The figure explaining the construction method of underground underground wall 30 The figure which shows the reinforcing bar rod 100

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
(1. underground continuous wall 30a)
Drawing 1 is a figure showing typically underground underground wall 30a concerning an embodiment of the present invention. The underground continuous wall 30a is a substantially cylindrical wall body constructed at a position surrounding the underground tank 10 (underground structure) with reinforced concrete or the like, similar to the underground continuous wall 30 in FIG. It reaches a depth exceeding the impermeable layer 21 such as a silt layer. Other configurations already described in FIG. 12 are denoted by the same reference numerals in the drawings and the description thereof is omitted.

  Similarly to the above, the underground continuous wall 30a is composed of a leading element (one element) and a trailing element (the other element) constructed in the excavation groove of the ground. When the underground continuous wall 30a is constructed, a rectangular excavation groove is formed in the ground at a predetermined interval in the circumferential direction of the underground continuous wall 30a, and the preceding element of the underground continuous wall 30a is constructed in the excavation groove. To do. Thereafter, a excavation groove is formed between the preceding element and the subsequent element of the underground continuous wall 30a is constructed in the excavation groove. The leading element is constructed by inserting a reinforcing bar into the excavation groove and placing concrete, and the trailing element is constructed by placing concrete around the reinforcing bar inserted into the excavation groove on the side of the preceding element. Is done. This procedure will be described later.

  In the present embodiment, at a depth corresponding to at least the water-impermeable layer 21, the gap 22 at the corner of the preceding element located in the vicinity of the connecting portion between the adjacent preceding element and the succeeding element is filled to form the closed portion 23. Is different from the underground continuous wall 30 in this respect.

  In the example of FIG. 1, the closed portion 23 is formed in a depth range including the impermeable layer 21 from the vicinity of the bottom surface of the underground tank 10 to the lower end of the underground continuous wall 30a. However, the closed part 23 should just be formed by the depth corresponding to the impermeable layer 21 at least, and the range can be defined variously. The same applies to the embodiments described later.

(2. Rebar rod 100a)
The construction method of the underground continuous wall 30a is basically the same as that described with reference to FIG. 13, but in this embodiment, the reinforcing bar used for construction of the preceding element is provided at the corner of the preceding element. A closing jig for filling the gap 22 to form the closing portion 23 is provided in advance.

  This reinforcing bar is shown in FIG. The reinforcing bar rod 100a in FIG. 2A is substantially the same as the reinforcing bar rod 100 described with reference to FIG. 14, and steel plates 111 (partition plates) are provided at both ends, and the corners of the plane of the reinforcing bar rod 100a. In the vicinity, a civil engineering sheet 112 that is a sheet in the length direction of the reinforcing bar 100 a and a presser plate 113 outside the civil engineering sheet 112 are attached to the steel plate 111. Other configurations already described in FIG. 14 are denoted by the same reference numerals in the drawings and the description thereof is omitted.

  In this embodiment, in the vicinity of the corner of the flat surface of the reinforcing bar 100a, the injection tube 120 is provided on the steel plate 111 of both end portions as the above-mentioned closing jig, and this point is different from the reinforcing bar 100 of FIG. Yes. The injection tube 120 is a bottomed tubular tube provided over almost the entire depth of the reinforcing bar 100a.

  FIG. 2B is a view showing the lower part of the injection tube 120. An injection hole 1201 for injecting an injection material into the gap 22 is provided on the outer peripheral surface at a depth corresponding to the above-described blocking portion 23 of the injection tube 120. In this embodiment, a plurality of injection holes 1201 having a diameter of about 15 mm are provided at intervals of about 3.0 m in the depth direction so that injection can be performed in multiple stages.

  In the injection tube 120, a cylindrical cover 121 is provided so as to cover the injection hole 1201. For example, a rubber tube is used for the cover 121. In the present embodiment, a plurality of covers 121 are attached to the positions of the respective injection holes 1201.

  The cover 121 is provided for preventing inflow of earth and sand and concrete of the succeeding element into the injection pipe, and preventing backflow of the injected material injected into the gap 22. On the other hand, the cover 121 is provided with a slit 1211 so that the injection material exiting from the injection hole 1201 of the injection tube 120 can be injected into the gap 22.

  The injection pipe 120 is installed only at a portion corresponding to the underground tank 10 (underground structure) side of the reinforcing bar 100a. The underground tank 10 side corresponds to the left side in FIG. 1, and corresponds to the upper side in FIG. 2A and FIGS. The right side of FIG. 1, the lower side of FIG. 2 (a) and FIGS. 3 to 11, opposite to this, is the ground side.

(3. Construction of underground continuous wall 30a)
In the present embodiment, when the underground continuous wall 30a is constructed, the reinforcing bar 100a is inserted into the excavation groove 20 formed by excavating the ground as shown in FIG. The concrete 31 is placed and filled in the excavation groove 20 as shown in FIG. Thereby, the preceding element 301a in which the reinforcing bar 100a is embedded in the concrete 31 is constructed.

  Thereafter, as shown in FIG. 3C, a digging groove is formed on the side of the preceding element 301a, the reinforcing bar 200 is inserted into the digging groove, and concrete 31 is placed around the reinforcing bar 200 and filled. . Thereby, the succeeding element 302a in which the reinforcing bar 200 is embedded in the concrete 31 is constructed.

  At this time, a substantially triangular gap 22 is formed at the corner of the preceding element 301a outside the presser plate 113 in the vicinity of the connecting portion between the preceding element 301a and the succeeding element 302a as described above. In the present embodiment, an injection material is injected into the gap 22 using the injection tube 120, and this is filled to form the closed portion 23 described above.

  In this embodiment, the inner tube 130 shown in FIG. 2C is inserted into the injection tube 120 to inject the injection material. A hole 1301 is provided at the lower end of the inner tube 130. The hole 1301 is about 15 mm in diameter, and packers 131 (bags) are provided above and below the hole 1301.

  As shown in FIG. 2 (d), the inner tube 130 is inserted into the injection tube 120 so that the injection hole 1201 is positioned between the upper and lower packers 131. Then, the packer 131 is inflated by, for example, sending in air and is brought into close contact with the inner wall of the injection pipe 120, and in this state, an injection material such as mortar or cement milk is injected from the inner pipe 130 at a high pressure. The injection material is delivered from the hole 1301, passes through the injection hole 1201 of the injection tube 120, exits from the slit 1211 of the cover 121, and is injected into the gap 22 at the corner of the preceding element 301a.

  In this embodiment, after that, the pressure of the packer 131 is released and contracted, the inner tube 130 is moved downward, and the injection material is injected from the lower injection hole 1201 in the same procedure as described above. This operation is repeated, and the injection material is injected into the entire range of the closed portion 23 described above.

  In this way, as shown in FIG. 3D and FIG. 1, the gap 22 at the corner of the preceding element 301 a is filled with the injection material to form the closed portion 23. In the present embodiment, only the gap 22 at the corner on the underground tank 10 side of the preceding element 301a is filled, and no injection material is injected into the ground-side gap 22, but this means that water remains in the ground-side gap 22 This is because there is no influence on the excavation inside the underground continuous wall 30a or the construction of the frame. As a result, the work can be simplified, but the gap 22 on the ground side can be filled with a similar method to form a closed portion.

  As described above, in the present embodiment, the gap 22 is formed by filling the gap 22 at the corner of the preceding element 301a at the depth corresponding to the impermeable layer 21 of the underground continuous wall 30a to form the closed portion 23. It is possible to prevent water leakage as water supply, and it becomes possible to easily excavate the ground and build the frame at the time of constructing the underground tank 10 inside the underground continuous wall 30a.

  In this embodiment, the injection material is injected using the injection pipe 120 provided in advance in the reinforcing bar 100a, so that the substantially triangular gap 22 generated at the corner of the preceding element 301a can be filled with the injection material. it can. Thus, it is possible to easily fill the gap 22 at the corner of the preceding element 301a without the need for boring and securing a space for inserting the injection tube into the gap 22 later. Since the injection pipe 120 is provided in the vicinity of the corner of the reinforcing bar 100a, the gap 22 in the vicinity thereof can be reliably filled with the injection material.

  Furthermore, in this embodiment, by providing a cover 121 with a slit around the injection hole 1201 of the injection tube 120, the inflow of the injection material can be prevented while preventing the inflow of earth and sand into the injection tube and the backflow of the injection material. An injection can be performed.

  Further, the inner tube 130 is inserted into the injection tube 120, and the injection material is injected from the inner tube 130 in a state where the upper and lower packers 131 of the hole 1301 of the inner tube 130 are in close contact with the inner wall of the injection tube 120. The material does not escape up and down, and reliable injection can be performed at high pressure. The inner tube 130 can be used repeatedly, and if the inside of the injection tube 120 is cleaned, reinjection is possible when the injection is insufficient.

  However, the present invention is not limited to this. Hereinafter, another example of the present invention will be described as second to fifth embodiments. Each embodiment will mainly describe differences from the embodiments described so far, and the same points will be denoted by the same reference numerals in the drawings and the like, and description thereof will be omitted.

[Second Embodiment]
The second embodiment is different from the first embodiment in that a mortar bag (bag) attached in advance to a reinforcing bar is used as a closing jig used to fill the corner of the preceding element.

  That is, in this embodiment, as shown in FIG. 4, in the vicinity of the corner of the plane of the reinforcing bar 100b, one end of the L-shaped steel 140 having a substantially L-shaped cross section is attached to the steel plate 111, and the L-shaped A mortar bag 150 is provided in a space surrounded by the steel 140 and the steel plate 111 in a substantially U shape.

  The L-shaped steel 140 and the mortar bag 150 are installed only in a portion corresponding to the underground tank 10 side of the reinforcing bar 100b as described above. Moreover, the mortar bag 150 is provided in the depth range corresponding to the obstruction | occlusion part 23 in the reinforcing bar 100b, and the injection pipe (not shown) not shown is inserted.

  In this embodiment, when constructing the preceding element of the underground continuous wall 30a, the reinforcing bar 100b is inserted into the excavation groove 20 formed by excavating the ground as shown in FIG. Then, the mortar bag 150 is filled with a filler such as early-strength mortar via the injection pipe, and the mortar bag 150 is inflated outwardly as shown in FIG. Thereby, before the concrete placement of the preceding element, the corner portion of the preceding element is first filled to form the closed portion 23.

  Then, after about one day, the preceding element concrete is placed in the same manner as described above to construct the preceding element. When the succeeding element is constructed in the same procedure as described above, the underground continuous wall 30a is formed.

  In the present embodiment, by filling the mortar bag 150 with a filler, the corners of the preceding element can be easily filled, and the same effect as in the first embodiment can be obtained. Moreover, by using the mortar bag 150 previously attached to the reinforcing bar 100b, it is possible to fill the corners prior to the concrete placement of the preceding element. There is a possibility that the mortar bag 150 may bulge out slightly from the steel plate 111 toward the trailing element side, but this portion is filled with concrete casting of the trailing element, so that no particular problem occurs.

  It is also possible to inflate the mortar bag 150 only in the range of the impermeable layer 21 to fill the corners of the preceding element. In other soil layer ranges, for example, the mortar bag 150 may be manufactured to have a small diameter, or may be sealed leaving a space for the injection tube to pass through. The same applies to a third embodiment described later.

[Third Embodiment]
As in the second embodiment, the third embodiment is an example in which a mortar bag is used as a closing jig used to fill the corners of the preceding element. In this embodiment, the mortar bag is used as the presser. Used by attaching to the plate 113.

  That is, in this embodiment, as shown in FIG. 6, the mortar bag 160 is provided outside the presser plate 113 in the vicinity of the corner of the flat surface of the reinforcing bar 100c. Similarly to the above, the mortar bag 160 is installed only in the part which hits the underground tank 10 side of the reinforcing bar 100c. Moreover, the mortar bag 160 is provided in the depth range corresponding to the obstruction | occlusion part 23 in the reinforcing bar 100c, and the injection pipe (not shown) which is not shown in figure is inserted.

  In the present embodiment, when constructing the preceding element of the underground continuous wall 30a, the reinforcing bar 100c is inserted into the excavation groove 20 formed by excavating the ground as shown in FIG. Then, as shown in FIG. 7 (b), the concrete 31 is placed in the excavation groove 20 and filled in the same manner as described above to construct the preceding element 301a. Thereafter, as shown in FIG. 7C, a digging groove is formed on the side of the preceding element 301a, the reinforcing bar 200 is inserted into the digging groove, and the concrete 31 is placed around the reinforcing bar 200 to follow. Build element 302a.

  At this time, as in the first embodiment, a substantially triangular gap 22 is generated at the corner of the preceding element 301a outside the presser plate 113 in the vicinity of the connecting portion between the preceding element 301a and the succeeding element 302a. In the present embodiment, the mortar bag 160 is filled with a filler such as mortar through the injection tube, and the mortar bag 160 is inflated to the outside as shown in FIG. . As a result, the gap 22 at the corner of the preceding element 301 a is filled to form the closed portion 23.

  Also in this embodiment, by using the mortar bag 160, the corners of the preceding element 301a can be easily filled, and the same effect as that of the first embodiment can be obtained.

  In this embodiment, a considerable frictional force can be expected by bringing the mortar bag 160 into strong contact with the steel plate 111 and the inner wall of the excavation groove 20 by high-pressure injection of a filler, and the mortar bag 160 is impervious to the water pressure from below. There is no slipping out above 21. The same applies to the second embodiment.

  Further, in this embodiment, after the concrete placement of the succeeding element 302a, the substantially triangular gap 22 generated at the corner of the preceding element 301a can be filled. It is also possible to fill the mortar bag 160 before filling the concrete of the element 302a and fill the corners of the preceding element 301a. Whether to fill the corner of the preceding element 301a before placing the concrete of the preceding element 301a as in the second embodiment, appropriately determine when to fill the corner in consideration of workability, construction period, etc. Can do.

[Fourth Embodiment]
The fourth embodiment is different from the first embodiment in that a movable part provided in advance in a reinforcing bar is used as a closing jig used to fill the corner of the preceding element.

  That is, in this embodiment, as shown in FIG. 8, one side of the L-shape of the L-shaped metal fitting 170 (sliding member) having a substantially L-shaped cross section as a movable portion in the vicinity of the corner of the flat surface of the reinforcing bar 100 d. Is attached to the steel plate 111, and the civil engineering sheet 112 is attached to the end of the L-shaped metal fitting 170 protruding inward from the steel plate 111. The L-shaped metal fitting 170 is installed only in the part which hits the underground tank 10 side of the reinforcing bar 100d. The L-shaped metal fitting 170 is provided in a depth range corresponding to the closing portion 23 in the reinforcing bar 100d.

  The L-shaped metal fitting 170 is provided so as to be slidable in the width direction of the reinforcing bar rod 100d. The sliding mechanism is not particularly limited. For example, the above-mentioned long holes in the width direction are provided at a plurality of upper and lower portions of the L-shaped metal fitting 170, and bolts with heads are passed through the long holes from the L-shaped metal fitting 170 side. It attaches to the steel plate 111 with.

  In the present embodiment, at the time of constructing the preceding element of the underground continuous wall 30a, the reinforcing bar 100d is inserted into the excavation groove 20 formed by excavating the ground as shown in FIG. 9A. Then, as shown in FIG. 9B, the concrete 31 is placed in the excavation groove 20 and filled in the same manner as described above to construct the preceding element 301a.

  At this time, the L-shaped metal fitting 170 is pushed out toward the inner wall of the excavation groove 20 on the side of the underground tank 10 as the civil engineering sheet 112 bulges outward by the pouring pressure of the concrete 31, and moves about 20 to 30 mm, for example. To substantially abut against the inner wall. Therefore, the corner portion of the preceding element 301a is filled with the concrete 31 inside the L-shaped metal fitting 170 to become the closed portion 23, and almost no gap is generated. When the succeeding element is constructed in the same procedure as described above, the underground continuous wall 30a is formed.

  Thus, in the present embodiment, the L-shaped metal fitting 170 moves together with the civil engineering sheet 112 when the preceding element 301a is placed in concrete and substantially abuts against the inner wall of the excavation groove 20, so that the preceding element inside the L-shaped metal fitting 170 is placed. The corners of 301a can be filled with concrete 31. Therefore, a gap is not generated in the corner and water is not used, and the same effect as in the first embodiment can be obtained.

[Fifth Embodiment]
As in the fourth embodiment, the fifth embodiment is an example in which a movable portion provided in advance in a reinforcing bar rod is used as a closing jig used to fill a corner portion of a preceding element. In the form, a movable part that rotates toward the inner wall of the excavation groove 20 is used.

  That is, in the present embodiment, as shown in FIG. 10, one end of the J-shape of the J-shaped bracket 180 (rotating member) having a substantially J-shaped cross section as a movable portion in the vicinity of the corner of the plane of the reinforcing bar 100e. Is attached to the steel plate 111 with a hinge 190, and the civil engineering sheet 112 is attached to the other end. The J-shaped bracket 180 can be rotated in a plane around the hinge 190. The J-shaped metal fitting 180 is installed only at a portion corresponding to the underground tank 10 side of the reinforcing bar 100e, and is provided in a depth range corresponding to the closed portion 23 in the reinforcing bar 100e.

  In this embodiment, when constructing the preceding element of the underground continuous wall 30a, the reinforcing bar 100e is inserted into the excavation groove 20 formed by excavating the ground as shown in FIG. Then, as shown in FIG. 11 (b), concrete 31 is placed in the excavation groove 20 and filled in the same manner as described above to construct the preceding element 301a.

  At this time, as the civil engineering sheet 112 bulges outward due to the placement pressure of the concrete 31, the J-shaped bracket 180 rotates around the hinge 190 toward the inner wall of the excavation groove 20 on the underground tank 10 side, and the inner wall Substantially abut. Therefore, the corner portion of the preceding element 301a is filled with the concrete 31 inside the J-shaped bracket 180 to form the closed portion 23, and almost no gap is generated. When the succeeding element is constructed in the same procedure as described above, the underground continuous wall 30a is formed.

  Thus, also in this embodiment, the J-shaped metal member 180 moves together with the civil engineering sheet 112 during the concrete placement of the preceding element 301a and substantially abuts against the inner wall of the excavation groove 20, whereby the preceding element inside the J-shaped metal member 180 is provided. The corners of 301a can be filled with concrete 31, and the same effect as in the first embodiment can be obtained. Whether the rotary member as in the present embodiment or the slide member as described above is used as the movable part can be appropriately determined according to workability and the like.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea disclosed in the present application, and these are naturally within the technical scope of the present invention. Understood.

10; underground tank 11; bottom slab 12; side wall 13; steel roof 20; excavation groove 21; impermeable layer 22; gap 23; closed part 30 and 30a: underground continuous wall 31; concrete 100, 100a, 100b, 100c, Reinforcing rods 101 and 102; Rebar 103; Tie rod 111; Steel plate 112; Civil engineering sheet 113; Press plate 120; Injection pipe 121; Cover 130; Inner pipe 131; Packer 140; L-shaped steel 150, 160; L-shaped metal fitting 180; J-shaped metal fitting 190; Hinge 301, 301a; Leading element 302, 302a; Trailing element 1201; Injection hole 1211; Slit 1301;

Claims (19)

Inserting a reinforcing bar with a partition plate at the end of the ground into the excavation groove of the ground, placing concrete, and building a leading element of the underground continuous wall;
By placing concrete in the excavation groove on the side of the preceding element and constructing the trailing element of the underground continuous wall,
The underground continuous wall is constructed so that the lower end reaches a depth exceeding the impermeable layer of the ground,
When building the underground continuous wall,
A block provided in advance in the vicinity of the corner of the reinforcing bar of the preceding element with the corner of the preceding element located in the vicinity of the connection between the preceding element and the succeeding element at a depth corresponding to the impermeable layer An underground continuous wall construction method characterized by filling with a jig for construction. The underground continuous wall is provided in a cylindrical shape at a position surrounding the underground structure,
2. The underground continuous wall construction method according to claim 1, wherein only a corner portion of the preceding element on the underground structure side is filled with the closing jig. The closing jig is an injection tube having an injection hole for injecting an injection material into a corner of the preceding element,
The underground continuous wall construction method according to claim 1 or 2, wherein an injection material is injected into the corner from the injection pipe to fill the corner.   4. The underground continuous wall construction method according to claim 3, wherein a cover having a slit is provided so as to cover the injection hole. When injecting an injection material into the corner of the preceding element,
Inserting an inner tube having a hole and a bag body above and below the hole into the injection tube,
Inflating the upper and lower bag bodies and closely contacting the inner wall of the injection tube;
The construction method of the underground continuous wall according to claim 3 or 4, wherein the injection material delivered from the hole of the inner pipe is injected from the injection hole into the corner of the preceding element. The closing jig is a bag,
The underground continuous wall construction method according to claim 1 or 2, wherein the bag body is filled with a filler to fill a corner of the preceding element. In the vicinity of the corner of the reinforcing bar rod, a sheet in the length direction of the reinforcing bar rod and a presser plate outside the sheet are attached to the partition plate,
7. The underground continuous wall construction method according to claim 6, wherein the bag body is provided outside the presser plate. The closing jig is a movable part provided near the corner of the reinforcing bar,
2. The concrete of claim 1, wherein when the concrete of the preceding element is placed, the movable portion substantially contacts the inner wall of the excavation groove, and the corner of the preceding element is filled with the concrete inside the movable portion. Or the construction method of the underground continuous wall of Claim 2. The movable part is a slide member attached to the partition plate and slidable in the width direction of the reinforcing bar rod,
The underground continuous wall construction method according to claim 8, wherein a sheet in a length direction of the reinforcing bar is attached to the slide member. The movable part is a rotating member attached to the partition plate and rotatable toward the inner wall of the excavation groove,
9. The underground continuous wall construction method according to claim 8, wherein a sheet in a length direction of the reinforcing bar is attached to the rotating member. An underground continuous wall having a plurality of adjacent elements constructed in a ground excavation groove,
The lower end of the underground continuous wall reaches a depth exceeding the impermeable layer of the ground,
One of the elements is composed of concrete filled in the excavation groove of the ground, embedded with a reinforcing bar with a partition plate in the end portion,
The other element is constructed by filling concrete in the excavation groove on the side of the one element,
In the depth corresponding to the impermeable layer, the corner of the one element located in the vicinity of the connecting portion of both elements is buried,
An underground continuous wall characterized in that a closing jig for filling a corner of the one element is provided in the vicinity of the corner of the reinforcing bar of the one element. The underground continuous wall is provided in a cylindrical shape at a position surrounding the underground structure,
The underground continuous wall according to claim 11, wherein only a corner on the underground structure side of the one element is buried. The closing jig is an injection tube having an injection hole for injecting an injection material into a corner of the one element.
The underground continuous wall according to claim 11 or 12, wherein the corner is filled with an injection material.   The underground continuous wall according to claim 13, wherein a cover having a slit is provided so as to cover the injection hole. The closing jig is a bag,
The underground continuous wall according to claim 11 or 12, wherein a corner portion of the one element is filled with the bag body filled with a filler. In the vicinity of the corner of the reinforcing bar rod, a sheet in the length direction of the reinforcing bar rod and a presser plate outside the sheet are attached to the partition plate,
The underground continuous wall according to claim 15, wherein the bag body is provided outside the presser plate. A movable part, which is the closing jig provided near the corner of the reinforcing bar, substantially contacts the inner wall of the excavation groove;
The underground continuous wall according to claim 11 or 12, wherein a corner portion of the one element is filled with concrete of the one element inside the movable portion. The movable part is a slide member attached to the partition plate and slidable in the width direction of the reinforcing bar rod,
The underground continuous wall according to claim 17, wherein a sheet in a length direction of the reinforcing bar is attached to the slide member. The movable part is a rotating member attached to the partition plate and rotatable toward the inner wall of the excavation groove,
The underground continuous wall according to claim 17, wherein a sheet in a length direction of the reinforcing bar is attached to the rotating member.

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