JP2022135026A - Preceding element of underground continuous wall, and connection structure and connection method of preceding element and following element of underground continuous wall - Google Patents

Abstract

To provide a preceding element of an underground continuous wall and a connection structure and a connection method of the preceding element and a following element of the underground continuous wall which can prevent collapse of a groove wall in a wall for an element in a construction of the underground continuous wall whose linear shapes in plan view cross in an L-shape etc., in which one end of the following element is connected to a connection area in a part of an end face including a long side of the preceding element.SOLUTION: In an underground continuous wall 100 in which a first end face 21 of a preceding element 20 is connected with a second end face 61 of a first following element 60, a fourth end face 71 of a second following element 70 is connected with a connection area 23 of a third end face 22 of the preceding element 20. The preceding element 20 includes: a partition plate 31 arranged in the connection area 23; a stud 32 protruding from the partition plate 31; and a space holding material 33 being at a third end face side of the partition plate 31 and capable of being cut by a ground excavation machine. A part of the space holding material 33 and a part of a concrete body 27 form a portion 35 to be cut.SELECTED DRAWING: Figure 4

Description

TECHNICAL FIELD The present invention relates to a leading element of a diaphragm wall, and a connection structure and method for connecting leading and trailing elements of a diaphragm wall.

A continuous underground wall is constructed by joining the leading element and the trailing element, which are underground walls that are constructed separately within a certain wall width, in order to ensure the stability of the hole wall of the excavated element groove. However, there is a problem that the construction of the joint (joint part, joint part) of the preceding element and the succeeding element is complicated.
In the construction of the preceding element, the space for the joint is ensured by not pouring the concrete up to the joint portion at the end of the element groove. At this time, in order to prevent the concrete from flowing out to the joint, measures such as taking measures such as using a partition plate and a sheet at the ends of the reinforcing bar cage are taken. In addition, when constructing trailing elements, protective plates are installed and removed before and after excavation to protect the joint reinforcing bars, but there is another issue that this temporary construction requires a lot of labor. ing.
Therefore, a sealed joint space is provided in advance at the end of the reinforcing bar cage of the preceding element, and in this state, concrete is placed up to the end of the groove for the preceding element, and then a rotary excavator or the like is used to form the groove for the succeeding element. is excavated, and at the same time, the concrete at the end of the leading element groove is cut so that the sealed joint space is opened in a concave shape, and the trailing element is constructed in the trailing element groove. , a method of connecting predecessor and successor elements has been developed.

The above construction method is called the Taisei Underground Diaphragm Walls Construction System (TUD construction method), and various proposals have been made regarding this TUD construction method. Among them, for example, in Patent Documents 1 and 2, both the end structure of the preceding element and the foundation that make it possible to easily and inexpensively construct a diaphragm wall with water cutoff and cross-sectional force transmission performance A construction method for medium-continuous walls has been proposed.

The end structure of the leading element described in Patent Document 1 includes a partition plate disposed at the boundary between the leading element and the trailing element, and a connecting member protruding from the side surface of the partition plate on the trailing element side. and a space forming member forming a space around the connecting member, wherein the space forming member includes a shape retaining portion attached to the distal end of the connecting member, and the connecting member and the shape retaining portion. At least the cover portion is cuttable by a ground excavator.
Further, the method for constructing a diaphragm wall described in Patent Document 1 includes a preceding excavation step of excavating a preceding excavated groove, a preceding forming step of forming a preceding element in the preceding excavated groove, and a subsequent element continuing to the preceding excavated groove. In a method for constructing a diaphragm wall comprising a subsequent excavation step of excavating an excavated groove and a subsequent formation step of forming a subsequent element continuous to the preceding element in the succeeding excavated groove, the preceding formation step comprises: A reinforcing bar cage and a partition plate are assembled to form a reinforcing bar unit, and a cover material that can be cut by a ground excavator is installed at the end of the reinforcing bar unit, and the connecting member protruding from the partition plate is attached to the cover material. Cover installation work to cover with, erection work to insert the reinforcing bar unit and cover material into the pre-excavated trench, insertion work to insert the shape-retaining material into the space surrounded by the partition plate and cover material, and the pre-excavated trench In the inserting work, a shape-retaining material is interposed between the tip of the connecting member and the cover material.

On the other hand, the end portion structure of the preceding element described in Patent Document 2 has a partition plate, a connection member, and a space forming member similar to Patent Document 1, and fills the space between the partition plate and the space forming member. Fig. 10 is an end structure of a preceding element further comprising granulated bodies so that the space forming member can be cut by a ground excavator;
In addition, the construction method for a diaphragm wall described in Patent Document 2 is a construction method that includes a preceding preparation step of forming a reinforcing bar unit for a preceding element, and a preceding excavation step to a subsequent forming step similar to Patent Document 1. The preliminary preparation process consists of assembling a reinforcing bar cage and a partition plate to the element frame to form a reinforcing bar unit, installing a space forming member that can be cut by a ground excavator at the end of the reinforcing bar unit, and installing a partition plate and a space forming member installation work for covering the connection member protruding from the space forming member with the space forming member, and the preceding forming step includes a setting work for inserting the reinforcing bar unit and the space forming member into the preceding excavated groove, a partition plate and the space This construction method includes a filling operation of filling the space surrounded by the forming member with the granular material, and a casting operation of placing concrete in the pre-excavated trench.

JP 2017-145595 A JP 2018-9388 A

According to the end structure of the preceding element and the construction method of the diaphragm wall described in Patent Documents 1 and 2, a diaphragm wall having water cutoff and cross-sectional force transmission performance can be constructed easily and inexpensively. .
By the way, in conventional diaphragm wall construction methods, including the construction methods described in Patent Documents 1 and 2, the end face of the leading element (end face including short sides at both ends) and the end face of the trailing element (end face at both ends) However, when constructing a diaphragm wall having an L-shaped, T-shaped, or cross-shaped planar view, these After excavating (cutting) the ground along the shape to create a groove for the element, a reinforcing bar cage is inserted and concrete is poured.
In the plan view shape described above, for example, a part of the end face including the long side of the preceding element is used as a connection region, and the end face including the short side at one end of the succeeding element is connected to this connection region. Therefore, when excavating the ground along a line in which the leading element and the trailing element, which are linear in plan view, are orthogonal to each other (linear lines such as L-shapes and T-shapes in plan view), There is a concern that the groove wall will collapse later at these corners and the like.

In the present invention, one end (end face including the short side) of the succeeding element is connected to a partial connection region of the end face including the long side of the preceding element, and the planar line-of-sight shape intersects in an L shape, a T shape, or the like. In the construction of a diaphragm wall to be constructed, the diaphragm wall can be constructed while preventing the collapse of the groove wall of the groove for the element to be created and connecting the leading element and the trailing element with high connection strength. It is an object of the present invention to provide a connection structure and a connection method for a leading element of an intermediate continuous wall and a leading element and a trailing element of a diaphragm wall.

In order to achieve the above object, one aspect of the preceding element of the diaphragm wall according to the invention comprises:
A diaphragm wall formed by interconnecting a first end face including the short side of the preceding rectangular element in plan view and a second end face including the short side of the first trailing element in plan view rectangular to each other in which the fourth end face including the short side of the separate second trailing element is connected to the connection area of the third end face including the long side of the preceding element, and the reinforcing bar cage is embedded. A preceding element of a diaphragm wall, which is a concrete body with
a partition plate disposed inside the third end face in the wall thickness direction in the connection region;
a stud projecting from the partition plate at least toward the third end surface;
a space retaining material disposed on the third end face side of the partition plate and capable of being cut by a ground excavator;
The space-retaining material is embedded inside the concrete body, and a part of the space-retaining material and a part of the concrete body located closer to the third end face than the space-retaining material are removed by the ground excavator. It is characterized by forming a cut portion to be cut.

According to this aspect, in the connection region of the third end face including the long side of the preceding element, the partition plate is disposed inside the third end face in the wall thickness direction, and the stud protrudes from the partition plate at least toward the third end face. A space holding material that can be cut by a ground excavator is arranged on the third end surface side of the partition plate, and a part of the space holding material and a part of the concrete body located on the third end surface side of the space holding material By forming the cut portion, one end of the second trailing element can be firmly connected to the connection region of the third end face including the long side of the leading element. In addition, by applying the preceding element of this aspect, after constructing the preceding element, a groove for the second succeeding element is formed in the ground corresponding to the connection area, and the second succeeding element is connected to the preceding element. Therefore, it is possible to efficiently construct the connection structure between the leading element and the second trailing element while preventing collapse of the created element groove.

Here, the first end face including the short sides at both ends of the leading element, which is rectangular in plan view, includes the short side at one end of the trailing element (first trailing element) as in a conventional diaphragm wall. A second end face is connected. In the leading element of this aspect, even in the element on the first end face to which the second end face of the first trailing element is connected, similarly to the connection region on the third end face, the partition plate and at least the first end face from the partition plate It is preferable that a stud protruding to the side and a space retaining member disposed on the first end face side of the partition plate and capable of being cut by a ground excavator are provided.
That is, the first end surface of the preceding element and the second end surface of the first succeeding element are connected by the above-described connection structure by the TUD construction method, and furthermore, the connection region of the third end surface of the preceding element and the separate second end surface The fourth end face of the second trailing element is also connected by the connection structure by the TUD construction method described above. As described above, the connecting region of the third end surface of the preceding element and the fourth end surface of the second succeeding element are connected to each other in an L-shape, a T-shape, or a cross shape in plan view.
Further, "the stud protrudes from the partition plate at least toward the third end surface" means that the stud protrudes from one wide side of the partition plate toward the third end surface, and that the stud protrudes from both wide sides of the partition plate. includes a form in which the protrudes.

Also in another aspect of the preceding element of the diaphragm wall according to the invention,
The reinforcing bar cage located at a position corresponding to the connection area has a recess recessed inward in the wall thickness direction of the preceding element,
The partition plate, the stud, and the space retaining member are accommodated in the recess.

According to this aspect, the reinforcing bar cage is provided with a concave portion that is recessed inward in the wall thickness direction of the preceding element, and the partition plate, the stud, and the space retaining member are accommodated in the concave portion. It becomes a cutting area by the excavator, and the cutting area is reinforced by the concave portion of the reinforcing bar cage, so that when the ground excavator cuts the part to be cut, the rotation that can occur in the connection area of the third end surface of the preceding element It is possible to prevent damage to the preceding element due to moment, eccentric load, and the like.
In addition, for example, a pillar forming an upper structure may be arranged at the connection structure (intersection) between the connection region on the third end face of the leading element and the fourth end face of the second trailing element. Part of the weight of the upper structure through the pillars concentrates on the connection structure, and there is concern about stress concentration. , corner chipping and cracking of concrete caused by stress concentration are suppressed.

In addition, one aspect of the connection structure of the preceding element and the succeeding element of the diaphragm wall according to the present invention is
A connection structure between a leading element and a trailing element of a diaphragm wall, wherein the connection region on the third end face of the leading element and the fourth end face of the second trailing element are connected,
The second trailing element is also a concrete body in which a reinforcing bar cage is embedded,
The interior of the space holding member is opened by cutting the portion to be cut in the connection region of the preceding element,
a connecting line extending from the interior of the space retaining member to the interior of the second trailing element;
The stud and the connecting bar are embedded in the concrete body of the second trailing element.

According to this aspect, for example, a plurality of connecting bars are arranged so as to straddle the inside of the second trailing element from the inside of the space retaining material in the cut portion of the connection region of the leading element, and partition Studs protruding from the plate and connecting bars are embedded in the concrete body of the second trailing element to provide a connection between the connection region of the third end face of the leading element and the fourth end face of the second trailing element. A connection structure with high strength can be formed.

Another aspect of the connecting structure of the leading element and the trailing element of the diaphragm wall according to the present invention is
In a fifth end face including the other long side facing the third end face of the preceding element, at least a region opposite to the connection region is provided with a widened portion having a relatively thick wall thickness of the preceding element. It is characterized by being

According to this aspect, of the fifth end face including the other long side facing the third end face of the preceding element, at least in the region opposite to the connection region, the widened portion having a relatively thick wall thickness of the preceding element is formed. By being provided, while having a connection structure with high connection strength between the leading element and the second trailing element, the support force and pull-out resistance of the diaphragm wall are increased at the widened portion in the vicinity thereof. can be achieved. Here, "the area on the opposite side of at least the connection area in the fifth end surface" means a mode in which the widened portion is provided only in the area on the opposite side of the connection area in the fifth end surface, and the fifth end surface is opposite to the connection area. For example, it includes a form in which a widened portion is provided in the entire area including the side area.

In addition to the preceding element, the diaphragm wall having the connection structure of this embodiment, in which the first trailing element and the second trailing element are provided with the widened portion (or widened bottom portion or extended portion) described above, has an aspect ratio of It is suitable for use as a foundation pile for high-rise buildings, super high-rise buildings, high-rise towers, etc., where the overturning moment is large and the pull-out force is a problem. This widened portion is sometimes referred to as a "projection" or "knot", and a plurality of protruding or knot-shaped widened portions are intermittently formed in the extending direction of the wall perpendicular to the wall thickness direction. and a form in which a widened portion is formed continuously in the extending direction of the wall.

In addition, one aspect of the method for connecting the preceding element and the succeeding element of the diaphragm wall according to the present invention is
A diaphragm wall formed by interconnecting a first end face including the short side of the preceding rectangular element in plan view and a second end face including the short side of the first trailing element in plan view rectangular to each other in which the fourth end face including the short side of the separate second succeeding element is connected to the connection area of the third end face including the long side of the preceding element, which is a concrete body in which the reinforcing bar cage is embedded; A method of connecting leading and trailing elements of a diaphragm wall, comprising:
a partition plate disposed inside the third end face in the wall thickness direction in the connection region;
a stud projecting from the partition plate at least toward the third end surface;
A step of constructing the preceding element having a space retaining material disposed on the third end face side of the partition plate and capable of being cut by a ground excavator;
A portion of the space holding member and a portion of the concrete body located closer to the third end face than the space holding member are used as portions to be cut, and the portion to be cut and the groove for the second trailing element are used as the ground. a B step of opening the interior of the space holding member to the groove for the second trailing element by cutting with an excavator;
A joining bar extending from the inside of the space holding member to the second trailing element groove is provided, and a part of the stud, the joining bar, and the reinforcing bar cage are embedded, and a C step of constructing a second trailing element and connecting the second trailing element to the connection region.

According to this aspect, after the preceding element is constructed in step A (preparation of the groove for the preceding element and construction of the preceding element), in step B, the cut portion of the preceding element and the groove for the second succeeding element are cut into the ground. The second created by cutting with an excavator, constructing the second trailing element in the C process, and connecting the connection region of the third end face of the leading element and the fourth end face of the second trailing element The connection structure of the leading element and the second trailing element can be efficiently constructed while preventing the collapse of the groove for the trailing element. The connection between the first end surface of the leading element and the second end surface of the first trailing element (conventional general connection) may be performed in parallel with the connection between the leading element and the second trailing element. , for example, may precede the connection of the preceding element and the second succeeding element.

In another aspect of the method for connecting leading and trailing elements of a diaphragm wall according to the present invention,
In the step A, a recess recessed inward in the wall thickness direction of the preceding element is formed in the reinforcing bar cage located at a position corresponding to the connection region, and the partition plate, the stud, and the space holding member are formed in the recess. It is characterized in that it accommodates

According to this aspect, in the step A, a recess recessed inward in the wall thickness direction of the preceding element is formed in the reinforcing bar cage, and the partition plate, the stud, and the space retaining material are accommodated in the recess, so that the cut portion is formed in the recess. is reinforced to prevent damage to the preceding element due to rotational moment, eccentric load, etc. that may occur in the connection area of the third end face of the preceding element when cutting the cut portion with the ground excavator. can be done.

In another aspect of the method for connecting leading and trailing elements of a diaphragm wall according to the present invention,
In the step A, the wall thickness of the preceding element is relatively thick at least in a region opposite to the connecting region in a fifth end face including the other long side facing the third end face of the preceding element. It is characterized by constructing a widened part.

According to this aspect, in step A, the wall thickness of the preceding element is relatively thick at least in the area opposite to the connection area in the fifth end surface including the other long side facing the third end surface of the preceding element. By constructing the widened part, it is possible to increase the bearing capacity and pull-out resistance of the diaphragm wall in the vicinity thereof while maintaining a connection structure with high connection strength between the leading element and the second trailing element. It is possible to construct a connection structure between the leading element and the trailing element (second trailing element) that can be done.
In addition, in the construction of this widening part, a wing-expanding excavator having a base machine and a wing-expanding excavating body suspended from the base machine by a wire is used to attach the wing-expanding excavator to the fifth end surface of the leading element. It is better to create a ditch. As an example of this wing-expanding excavating body, a rotating shaft extending in a direction perpendicular to the wall thickness of the leading element groove in a plan view, a frame having a stabilizer for applying a reaction force to the leading element groove, and a rotating shaft and a rotary drive means for rotating the blade expansion cutter with respect to the rotary shaft.

According to the preceding element of the diaphragm wall and the connection structure and connection method of the preceding element and the succeeding element of the diaphragm wall of the present invention, the connection region of the end face (third end face) including the long side of the preceding element Element created in the construction of a diaphragm wall where the plane line of sight crosses L-shaped or T-shaped, etc., where one end (fourth end face) of the trailing element (second trailing element) is connected to To construct a diaphragm wall while preventing collapse of a groove wall of a groove (a groove for a second trailing element) and connecting a leading element and a trailing element (second trailing element) with high connection strength. can be done.

FIG. 4 is a plan view of an example of a preceding element of a diaphragm wall according to an embodiment, and a process diagram showing an example of a method of connecting a preceding element and a succeeding element of a diaphragm wall according to an embodiment. FIG. 2 is a view taken along the line II-II in FIG. 1 and a longitudinal cross-sectional view of the preceding element; FIG. 10 is a plan view of another example of a leading element of a diaphragm wall according to embodiments; FIG. 4 is a plan view showing an example of a connection structure between the leading element and the trailing element of the diaphragm wall according to the embodiment, and an example of a method of connecting the leading element and the trailing element of the diaphragm wall according to the embodiment; It is a process diagram showing. It is process drawing which shows an example of the connection method of the preceding element of a diaphragm wall and a succeeding element which concern on embodiment. FIG. 10 is a diagram for explaining a method of forming general grooves for forming preceding element grooves; FIG. 10 is a diagram for explaining a method of creating a widened groove for forming a preceding element groove; 5 and 1, it is a process drawing showing an example of a method of connecting the preceding element and the succeeding element of the diaphragm wall according to the embodiment.

Hereinafter, the leading element of the diaphragm wall and the connection structure and connection method of the leading element and the trailing element of the diaphragm wall according to the embodiment will be described with reference to the accompanying drawings. In addition, in the present specification and drawings, substantially the same components may be denoted by the same reference numerals, thereby omitting duplicate descriptions.

[Preceding Element of Diaphragm Wall According to Embodiment and Connection Structure of Preceding Element and Subsequent Element of Diaphragm Wall]
First, with reference to FIGS. 1 to 4, an example of a leading element of a diaphragm wall according to an embodiment and a connection structure between the leading element and the trailing element of the diaphragm wall will be described. Here, FIG. 1 is a plan view of an example of the leading element of the diaphragm wall according to the embodiment, and FIG. 2 is a view taken along line II-II in FIG. be. 3 is a plan view of another example of the preceding element of the diaphragm wall according to the embodiment, and FIG. 4 is a connection structure of the preceding element and the succeeding element of the diaphragm wall according to the embodiment. It is a top view which shows an example. 1 and 4 are process diagrams showing an example of a method of connecting leading elements and trailing elements of a diaphragm wall according to the embodiment, and will also be referred to in the following description of the connection method.

The preceding element 20 shown in FIG. 1 has a general portion 20A that is rectangular in plan view, and widened portions 20B provided on the third end face 22 and the fifth end face 24 along the longitudinal direction thereof. Note that the preceding element may have a form having only a general rectangular portion in a plan view.

The general portion 20A of the leading element 20 has a first end face 21 including short sides, and a third end face 22 and a fifth end face 24 including long sides. The leading element and the trailing element generally form a diaphragm wall by joining the end faces including both short sides, but the leading element 20 shown in the figure has a first end face 21 on the left side in FIG. In addition to the conventional configuration in which the cut first end face 21′ (see FIG. 4) after cutting and the second end face 61 (see FIG. 4) of the first trailing element 60 are connected, the A fourth end face 71 (see FIG. 4) of the second trailing element 70 which has a connecting region 23 on the third end face 22 and which is separate from the third end face 22′ after cutting in the connecting region 23 (see FIG. 4). is connected.

Returning to FIG. 1, the general portion 20A of the preceding element 20 constructed inside the ground G comprises a concrete body 27 and a reinforcing bar cage 25 embedded therein.

Inside the first end face 21 of the general portion 20A, there are a partition plate 31, studs 32 protruding from the partition plate 31 on both sides thereof, and a space provided on the first end face 21 side of the partition plate 31. A holding member 33 is provided.

The space holding member 33 has a substantially U-shape in plan view and is made of vinyl chloride or the like that can be easily excavated by a ground excavator. A substantially rectangular space K in plan view is formed on the third end face side of the partition plate 31 by abutting the end portion of the space holding member 33 against the flat partition plate 31 .

A portion of the space holding member 33 and a portion of the concrete body 27 closer to the first end face 21 than the space holding member 33 form a cut portion 35 to be cut by a ground excavator 200 (see FIG. 6).

The leading element 20 has a portion to be cut inside the connecting region 23 (the third end face 22' after cutting) of the third end face 22 connected to the fourth end face 71 (see FIG. 4) of the second trailing element 70. 35, and a cut portion 35 is also provided inside the first end face 21 (first end face 21′ after cutting) connected to the second end face 61 (see FIG. 4) of the first trailing element 60. have.

Further, the reinforcing bar cage 25 in the leading element 20 at a position corresponding to the connection region 23 has a concave portion 26 recessed inward in the wall thickness direction of the leading element 20 .

The concave portion 26 provided in the reinforcing bar cage 25 includes a wall thickness direction reinforcing bar 26a arranged on the left side of the connection region 23 and a wall longitudinal direction arranged so as to overlap the stud 32 extending inward in the wall thickness direction. It has a reinforcing bar 26b and a wall-thickness oblique reinforcing bar 26c disposed on the right side of the connection region 23, and these reinforcing bars overlap each other to form a concave shape in plan view. Instead of the wall thickness direction reinforcing bar 26a extending in the wall thickness direction, the wall thickness direction reinforcing bar may be a wall thickness direction reinforcing bar that inclines to the opposite side (diagonally upward to the right in FIG. 1) of the wall thickness direction reinforcing bar 26c.

The reinforcing bar cage 25 has a recess 26 recessed inward in the wall thickness direction of the preceding element 20, and the partition plate 31, the stud 32, and the space retaining member 33 are accommodated in the recess 26. The inner side becomes a cutting area by the ground excavator 200 (see FIG. 6), and the cutting area is reinforced by the concave portion 26 of the reinforcing bar cage 25 . As a result, when the ground excavator 200 cuts the portion 35 to be cut, the leading element 20 is prevented from being damaged due to rotational moment, eccentric load, etc. that may occur in the connection region 23 of the third end surface 22 of the leading element 20. can be prevented.

In the region of the preceding element 20 having the widened portions 20B on the left and right sides of the general portion 20A, as shown in FIG. Also, although illustration is omitted, in a region having only one of the left and right widened portions 20B of the general portion 20A, only one of the left and right widened portions 20B shown in FIG. 2 is provided. In addition, in FIG. 2, illustration of the reinforcing bar cage in the general part 20A is omitted.

Another example of the preceding element 20 shown in FIG. 3 differs from the recess 26 of the preceding element 20 shown in FIG.

The recess 26A is connected to a wall thickness direction reinforcing bar 26a arranged on the left side of the connection region 23 and a wall longitudinal direction reinforcing bar 26b arranged so as to overlap the stud 32 extending inward in the wall thickness direction. It has a wall-thickness-direction reinforcing bar 26d disposed on the right side of the region 23, and these reinforcing bars overlap each other to form a recessed shape in plan view.

Also in the recess 26A, the partition plate 31, the stud 32, and the space retaining member 33 are accommodated in the recess 26A, so the inside of the recess 26A provided in the reinforcing bar cage 25 becomes a cutting area by the ground excavator 200 (see FIG. 6). , the cutting area is reinforced by the recess 26 of the reinforcing bar cage 25 .

Next, referring to FIG. 4, the connection structure between the leading element 20 and the second trailing element 70 will be described together with the connection structure between the leading element 20 and the first trailing element 60. FIG.

First, the connection structure 80 between the leading element 20 and the first trailing element 60 is the first end face after cutting, in which the first end face 21 including the short side of the leading element 20 is cut, as in the conventional connection structure. 21' is formed by connecting the second end face 61 including the short side of the first trailing element 60. As shown in FIG.

Inside the first end face 21 of the preceding element 20, part of the space holding member 33 and part of the concrete body 27 closer to the first end face 21 than the space holding member 33 are cut. A first end face 21' is formed. In the first end surface 21' after cutting, from the space (initial space K) inside the space holding member 33 partially cut to the concrete body 67 of the general portion 60A of the first trailing element 60, A plurality of connection muscles 34 are provided.

When the concrete body 67 of the general portion 60A of the first trailing element 60 is constructed, fresh concrete is also filled into the space inside the space holding member 33, thereby spanning both the concrete bodies 27 and 67. A connecting structure 80 of the first trailing element 60 and the leading element 20 is formed, having a plurality of studs 32 and connecting lines 34 . Here, the first trailing element 60 has a general portion 60A formed by embedding a reinforcing bar cage 65 inside a concrete body 67, and widened portions 60B on the left and right of the general portion 60A.

In the illustrated example, the widened portion 20B of the leading element 20 and the widened portion 60B of the first trailing element 60 are continuous in the longitudinal direction.

On the other hand, the connection structure 90 between the leading element 20 and the second trailing element 70 differs from the conventional connection structure in that the third end surface 23 after cutting is formed in the connection region 23 of the third end surface 22 including the long side of the leading element 20 . A fourth end face 71 including the short side of the second trailing element 70 is connected to the end face 22'.

In the connection region 23 of the third end face 22 of the leading element 20, part of the space holding member 33 and part of the concrete body 27 closer to the first end face 21 than the space holding member 33 are cut. A rear third end face 22' is formed. In the third end face 22' after cutting, from the space (initial space K) inside the space holding member 33 partially cut to the concrete body 77 of the general portion 70A of the second trailing element 70, A plurality of connection muscles 34 are provided.

When the concrete body 77 of the general portion 70A of the second trailing element 70 is constructed, the fresh concrete is also filled in the space inside the space retaining member 33, so that the concrete bodies 27 and 77 are straddled. A connecting structure 90 between the second trailing element 70 and the leading element 20 (an example of the connecting structure between the leading element and the trailing element of the diaphragm wall according to the embodiment) having a plurality of studs 32 and connecting bars 34. It is formed. Here, the second trailing element 70 has a general portion 70A formed by embedding a reinforcing bar cage 75 inside a concrete body 77, and widened portions 70B on the left and right of the general portion 70A.

In the illustrated example, the second trailing element 70 has widened portions 70B on the left and right sides of the general portion 70A.

In addition to connecting the leading element 20 and the first trailing element 60 to each other via the connection structure 80 in the lateral direction of the paper surface of FIG. At 23, a separate second trailing element 70 is connected to each other through a connecting structure 90 so as to be orthogonal to the leading element 20, thereby forming a diaphragm wall 100 in plan view L. As shown in FIG.

In the fifth end surface 24 facing the third end surface 22 of the preceding element 20, at least in the region opposite to the connection region 23, the widened portion 20B having a relatively thick wall thickness of the preceding element 20 is provided. , while having a connection structure 90 with high connection strength between the leading element 20 and the second trailing element 70, the support force and pullout resistance of the diaphragm wall 100 are increased at the widened portion 20B in the vicinity thereof. can be planned.

The underground continuous wall 100 has a plurality of leading elements 20 and first trailing elements 60 alternately arranged in the longitudinal direction (horizontal direction of the paper surface in FIG. 4) and connected to each other via a connection structure 80. A second trailing element 70 is connected to the right corner portion via a connection structure 90 shown in FIG. The elements are connected via connecting structures 80 .

Although not shown in the drawings, the diaphragm wall may also be connected to the connecting region 23 of the third end surface 22 of the leading element 20 at an intermediate position in the longitudinal direction via the connecting structure 90. It may be a T-shaped underground continuous wall formed by connecting the second trailing element 70 with In addition, the second trailing element 70 is connected via the connection structure 90 to each of the third end face 22 and the fifth end face 24 of the leading element 20 at an intermediate position in the longitudinal direction. It may be a cross-shaped underground continuous wall in plan view.

[Method for Connecting Leading Element and Trailing Element of Diaphragm Wall According to Embodiment]
Next, with reference to FIGS. 5, 1, 6 to 8, and 4, an example of a method for connecting leading elements and trailing elements of a diaphragm wall according to the embodiment will be described. Here, FIGS. 5, 1, 8, and 4 are step diagrams sequentially showing an example of a method of connecting leading elements and trailing elements of the diaphragm wall according to the embodiment. FIG. 6 and FIG. 7 are diagrams for explaining a method of forming a general groove and a widened groove, respectively, which form the preceding element groove.

First, as shown in FIG. 1, a preceding element groove 10 extending to a predetermined depth in the ground G is formed. In forming the leading element groove 10, after forming the general groove 11, the widened groove 12 is formed on the side of the general groove 11. As shown in FIG.

Here, with reference to FIGS. 6 and 7, a method for forming the general groove 11 and the widened groove 12 will be described.

6A and 6B are diagrams for explaining a method for forming the general groove 11. FIG. The general ditch 11 is created, for example, by a general excavator 200, which is a low-head horizontal multi-axis excavator shown in the figure.

A pair of left and right cutters provided in the general excavator 200 is a horizontal two-axis rotary cutter 210 disposed at the lower end of the excavator body, and is connected to the hydraulic unit via a power cable (neither is shown). and is rotated by the driving force of the hydraulic unit to loosen the ground G. Further, the mud pump 220 is connected to a sediment separator (not shown) through a hose, sucks up the sediment together with the hole water from the general groove 11, and sends it to the sediment separator.

After forming the general groove 11 to a predetermined depth, the widened groove 12 is formed on the side of the general groove 11. - 特許庁7A and 7B are diagrams for explaining a method for forming the widened portion groove 12. FIG.

The expanded wing excavator 300 includes a base machine 310 composed of a crawler crane that can freely travel on the ground surface of the ground G, a wire 320 suspended from the boom of the base machine 310, and an expander attached to the tip of the wire 320. and a wing excavation body 330 . In addition to the crawler crane, the base machine may be other heavy equipment such as a truck crane that can freely travel and wire the wing-expanded excavator 330 into the excavation hole via the wire 320 .

The wing-expanding excavator 330 includes a frame 331 constructed by assembling steel materials, a stabilizer 332 extending and retracting toward the groove wall on the side of the frame 331, and a rotating shaft 334 at the lower end of the frame 331 so as to be rotatable. It has a plurality of wing cutters 333 attached.

The general groove 11 shown in FIG. 7 is illustrated so that the wall thickness direction can be visually recognized, and the direction perpendicular to the wall thickness direction of the preceding element groove 10 (longitudinal direction of the preceding element groove 10) is perpendicular to the paper surface. direction.

The illustrated blade expanding cutter 333 rotates in the wall thickness directions X1 and X2 about a rotary shaft 334 extending in a direction perpendicular to the wall thickness of the leading element groove 10, thereby rotating the widened portion. A groove 12 is created. FIG. 7 shows a method of forming the widened grooves 12 on the two wide surfaces of the general groove 11, respectively. The wing expansion cutter 333 should only be rotated.

7 has a mud lifting pump 340 placed on the ground, and a flow pipe 338 communicating with a mud discharge passage (not shown) of a blade expansion cutter 333. communicates with the mud pump 340 . By operating the mud-lifting pump 340, it is possible to discharge the mud generated by excavation by the wing expanding cutter 333 to the ground. As with the excavator, the expanded wing excavator 300 is also capable of discharging mud.

By constructing the widened groove 12 using the wing expander excavator 300, even if a site boundary exists in the construction area, the widened groove 12 can be constructed only on one side opposite to the site boundary. . In addition, by forming the widened groove 12 by applying a reaction force to the groove wall of the general groove 11, the corner portion of the second trailing element groove 50 (see FIG. 8) perpendicular to the leading element 20 is formed. It becomes possible to form the widened groove 52 even at or near it. Further, the leading element groove 10 and the second trailing element groove 50 which are orthogonal to each other can be formed as grooves having the same depth.

As shown in FIGS. 6 and 7, the leading element groove 10 shown in FIG. 5 is formed by forming the general groove 11 and the widened groove 12 using respective excavators.

A reinforcing bar cage 25 is inserted into the created groove 10 for preceding elements. A concave portion 26 is formed in the reinforcing bar cage 25 in the vicinity of the connection region 23 by arranging wall thickness direction reinforcing bars 26a, wall longitudinal direction reinforcing bars 26b, and wall thickness oblique reinforcing bars 26c. Further, in the vicinity of the first end surface 21 of the leading element 20 and in the vicinity of the connection region 23 of the third end surface 22, a partition plate 31 with a stud 32 projecting therefrom and a space retaining member 33 are provided.

After that, by placing concrete in the groove 10 for the preceding element, the preceding element 20 is constructed as shown in FIG. 1 (above, step A).

Next, as shown in FIG. 8, on the first end face 21 of the leading element 20, a portion of the space holding member 33 and a portion of the concrete body 27 on the first end face side of the space holding member 33 are cut. 35, the portion to be cut 35 and the general groove 41 are cut by the general excavator 200 shown in FIG. By this cutting, the first end face 21 is cut to form a first end face 21' after cutting, and at the same time, the general groove 41 is formed. The first trailing element groove 40 is formed by forming the left and right widening grooves 42 using the general groove 41 with a wing expansion excavator 300 shown in FIG. 7 .

Simultaneously with or before or after the first trailing element groove 40, cutting of the connecting region 23 of the third end surface 22 of the leading element 20 and formation of the second trailing element groove 50 are performed. By this cutting, the interior of the space holding member 33 is opened to the first trailing element groove 40 .

This creation is also performed in the same manner as the creation of the groove 40 for the first trailing element. A portion of the concrete body 27 located on the third end face side of the second end surface is used as a portion to be cut 35, and the portion to be cut 35 and the general portion groove 51 are cut by the general portion excavator 200 shown in FIG. By this cutting, the connection region 23 of the third end face 22 is cut to form the third end face 22' after cutting, and at the same time, the general groove 51 is formed. The second trailing element groove 50 is formed by forming the left and right widening grooves 52 using the general groove 51 with the wing expansion excavator 300 shown in FIG. 7 . By this cutting, the inside of the space holding member 33 is opened to the second trailing element groove 50 (the above is the B step).

Next, a reinforcing bar cage 65 is inserted into the groove 40 for the first trailing element, and a plurality of connecting bars 34 are arranged from the space inside the partially cut space holding member 33 to the general groove 41. , concrete is placed in the groove 40 for the first trailing element. Similarly, a reinforcing bar cage 75 is inserted into the second trailing element groove 50, and a plurality of connecting bars 34 are arranged from the space inside the partially cut space holding member 33 to the general groove 51. and pour concrete into the groove 50 for the second trailing element. Concrete bodies 67 and 77 are respectively formed by these concrete placements, and as shown in FIG. A diaphragm wall 100 is constructed to which the trailing elements 70 are connected via connecting structures 90 .

Thus, after constructing the preceding element 20, the groove 50 for the second succeeding element can be formed in the ground G corresponding to the connection region 23, and the second succeeding element 70 can be connected to the preceding element 20. Therefore, the connection structure 90 between the leading element 20 and the second trailing element 70 having an L-shape, a T-shape, or a cross shape in a plan view can be efficiently formed while preventing the formed groove 50 for the second trailing element from collapsing. (above, C process).

In the connection structure 90 to be constructed, the reinforcing bar cage 25 is provided with a recess 26 recessed inward in the wall thickness direction of the preceding element 20, and the recess 26 accommodates the partition plate 31, the stud 32, and the space retaining member 33. The inner side of the recessed portion 26 provided in the reinforcing bar cage 25 becomes the cutting area by the ground excavator 200, and the cutting area is reinforced by the recessed portion 26 of the reinforcing bar cage 25. In doing so, the connection area 23 of the preceding element 20 is prevented from being damaged.

It should be noted that other embodiments may be possible in which other components are combined with the configurations described in the above embodiments, and the present invention is not limited to the configurations shown here. Regarding this point, it is possible to change without departing from the gist of the present invention, and it can be determined appropriately according to the application form.

10: Leading element groove 11: General groove 12: Widening groove 20: Leading element 20A: General part 20B: Widening part 21: First end face 21': First end face after cutting 22: Third end face 22': Third end face after cutting 23: Connection region 24: Fifth end face 25: Reinforcement cage 26, 26A: Recess 26a, 26d: Wall thickness direction reinforcement 26b: Wall longitudinal direction reinforcement 26c: Wall thickness oblique direction reinforcement 27: Concrete body 31 : Partition plate 32: Stud 33: Space retaining material 34: Joining bar 35: Cut portion 40: Groove for first trailing element 41: Groove for general portion 42: Groove for widened portion 50: Groove for second trailing element 51: General part groove 52: Widened part groove 60: First trailing element 60A: General part 60B: Widened part 61: Second end face 65: Rebar cage 67: Concrete body 70: Second trailing element 70A: General part 70B: Widening Part 71: Fourth end face 75: Reinforcing bar cage 77: Concrete body 80: Connection structure 90: Connection structure (connection structure of leading element and trailing element of diaphragm wall)
100: Diaphragm wall 200: General excavator (ground excavator)
210: Rotary cutter 220: Mud lifting pump 300: Wing expansion excavator (ground excavator)
310: Base machine 320: Wire 330: Wing expansion excavating body 331: Frame 332: Stabilizer 333: Wing expansion cutter 334: Rotating shaft 340: Mud lifting pump G: Ground K: Space

Claims (7)

A diaphragm wall formed by interconnecting a first end face including the short side of the preceding rectangular element in plan view and a second end face including the short side of the first trailing element in plan view rectangular to each other in which the fourth end face including the short side of the separate second trailing element is connected to the connection area of the third end face including the long side of the preceding element, and the reinforcing bar cage is embedded. A preceding element of a diaphragm wall, which is a concrete body with
a partition plate disposed inside the third end face in the wall thickness direction in the connection region;
a stud projecting from the partition plate at least toward the third end surface;
a space retaining material disposed on the third end face side of the partition plate and capable of being cut by a ground excavator;
The space-retaining material is embedded inside the concrete body, and a part of the space-retaining material and a part of the concrete body located closer to the third end face than the space-retaining material are removed by the ground excavator. A preceding element of a diaphragm wall, characterized in that it forms a cut to be cut. The reinforcing bar cage located at a position corresponding to the connection area has a recess recessed inward in the wall thickness direction of the preceding element,
2. Preceding element of diaphragm wall according to claim 1, characterized in that the partition plate, the stud and the space retainer are accommodated in the recess. 3. Leading and trailing elements of a diaphragm wall, wherein said connecting region at said third end face of said leading element according to claim 1 or 2 and said fourth end face of said second trailing element are connected. A connecting structure of elements,
The second trailing element is also a concrete body in which a reinforcing bar cage is embedded,
The interior of the space holding member is opened by cutting the portion to be cut in the connection region of the preceding element,
a connecting line extending from the interior of the space retaining member to the interior of the second trailing element;
A connecting structure of a leading element and a trailing element of a diaphragm wall, wherein the stud and the connecting bar are embedded in the concrete body of the second trailing element. In a fifth end face including the other long side facing the third end face of the preceding element, at least a region opposite to the connection region is provided with a widened portion having a relatively thick wall thickness of the preceding element. The connecting structure of the leading element and the trailing element of the diaphragm wall according to claim 3, characterized in that it is A diaphragm wall formed by interconnecting a first end face including the short side of the preceding rectangular element in plan view and a second end face including the short side of the first trailing element in plan view rectangular to each other in which the fourth end face including the short side of the separate second succeeding element is connected to the connection area of the third end face including the long side of the preceding element, which is a concrete body in which the reinforcing bar cage is embedded; A method of connecting leading and trailing elements of a diaphragm wall, comprising:
a partition plate disposed inside the third end face in the wall thickness direction in the connection region;
a stud projecting from the partition plate at least toward the third end surface;
A step of constructing the preceding element having a space retaining material disposed on the third end face side of the partition plate and capable of being cut by a ground excavator;
A portion of the space holding member and a portion of the concrete body located closer to the third end face than the space holding member are used as portions to be cut, and the portion to be cut and the groove for the second trailing element are used as the ground. a B step of opening the interior of the space holding member to the groove for the second trailing element by cutting with an excavator;
A joining bar extending from the interior of the space holding member to the second trailing element groove is disposed, and the stud, the joining bar, and the reinforcing bar cage are embedded to form the second rear element. and C step of constructing a row element and connecting said second trailing element to said connection area. In the step A, a recess recessed inward in the wall thickness direction of the preceding element is formed in the reinforcing bar cage located at a position corresponding to the connection region, and the partition plate, the stud, and the space holding member are formed in the recess. 6. A method of connecting leading and trailing elements of a diaphragm wall according to claim 5, characterized in that it accommodates a. In the step A, the wall thickness of the preceding element is relatively thick at least in a region opposite to the connecting region in a fifth end face including the other long side facing the third end face of the preceding element. 7. A method for connecting leading and trailing elements of a diaphragm wall according to claim 5 or 6, characterized in that a widening is applied.

Images