JP2002275886A - Method of constructing cross part of underground continuous wall - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily secure the continuity of steel wall connecting member in a cross part in the case of inserting the steel wall connecting member into the underground continuous walls provided in two directions and crossing to each other in order to improve the proof stress. SOLUTION: After constructing the underground continuous wall 1 in one of two directions crossing each other to a part in this side of a crossing part 30 crossing the underground continuous wall 2 provided in the other direction, an enlarged width wall 3 continued to the underground continuous wall 1 and having a wall thickness larger than that of the wall 1 is constructed to a position crossing the underground wall 2 provided in the other direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
Construction method of underground continuous wall intersection to ensure continuity of steel continuous wall members at intersections when steel connecting members are inserted in direction of underground continuous walls to improve strength Things.

[0002]

2. Description of the Related Art While circulating an endless chain having a cutting blade around a cutter post, the cutter post is traversed while being inserted into the ground, and at the same time, the lower end of the cutter post, or A method of constructing an underground continuous wall having a predetermined wall thickness by discharging an injection liquid such as a solidifying material liquid from the vicinity of the ground surface is disclosed in, for example,
And Japanese Patent Application Laid-Open No. 11-117349 are all limited to the construction of a straight underground continuous wall, and an underground continuous wall having an angle cannot be continuously constructed.

In order to construct an underground continuous wall having an angle, the entire cutter post is once pulled out from the underground at the intersection, and the cutter post is changed together with the construction apparatus in that state, and a new continuous wall is newly formed. The cutter post is buried underground in the same way as when starting construction.It is difficult to change the direction with the cutter post inserted in the ground, so it is difficult to change the direction of the underground wall including the intersection. The wall thickness will be equal in each direction.

[0004] When a steel continuous wall member having an H-shaped cross section having joints on both sides is inserted as a core material for reinforcement inside the underground continuous wall, the wall thickness of the underground continuous wall is made of steel. Because it is determined by the composition (height in the weak axis direction) including the joints of the wall members, the underground continuous wall in a certain direction is made of steel over the entire length up to the intersection with the underground continuous wall in the crossing direction. Since it is constructed with a constant wall thickness according to the structure of the continuous wall member, it is difficult to insert the steel continuous wall member at the intersection.

For example, in order to make the steel connecting wall members in each direction continuous at the intersection where the underground continuous walls in two directions are orthogonal to each other, one side in the width direction and one side in the forming direction are attached to the steel connecting wall members at the intersection. It is necessary to have joints in the two directions, but since the joints also have a joint in the forming direction, the composition is larger than the steel continuous wall member inserted in the part other than the intersection, so the underground continuous wall If the wall thickness is constant up to the intersection, a steel continuous wall member having joints in two directions cannot be inserted into the intersection.

Even if the steel continuous wall member can be inserted to the intersection of the underground continuous wall in the preceding direction by suppressing the protrusion of the joint in the forming direction, etc. In the case where time elapses from the end of construction to the start of construction of the underground continuous wall in the crossing direction, construction of the underground continuous wall to be constructed later is started, and when it reaches the intersection, it precedes If the soil cement at the intersection of the underground continuous wall is hardened, the steel continuous wall member facing the intersection may not be able to be inserted on the underground continuous wall side to be constructed later.

As described above, from the viewpoint of the thickness of the underground continuous wall,
From the viewpoint of the construction procedure, it is difficult to connect the steel continuous wall member inserted into the underground continuous wall to be subsequently constructed to the steel continuous wall member at the intersection. In one of the two directions, the steel connecting wall member in one direction is inserted up to the intersection, and the steel connecting member in the other direction must be inserted in a form to abut against the steel connecting member at the intersection, The continuity of the steel continuous wall member at the intersection is not ensured.

[0008] Although the intersection is the location where the stress conditions are the most severe, the two-way steel continuous wall member is not connected, and thus becomes a structural weak point. Since it is easily separated, there is a high risk of cracking and breaking.

In view of the above background, the present invention proposes a method of constructing an underground continuous wall which can eliminate structural weak points at intersections.

[0010]

According to the present invention, an underground continuous wall in one of two intersecting directions is constructed up to near an intersection with an underground continuous wall in another direction, and then the underground continuous wall is constructed. By constructing a widened wall continuous with the continuous wall and having a wall thickness larger than the wall thickness to a position where the widened wall intersects the underground continuous wall in the other direction, 2
A steel connecting wall member having a joint in the direction can be inserted into the intersection.

The wall thickness of the widening wall should be at least large enough to insert a steel continuous wall member having a joint in two directions as described in claim 3 from the viewpoint of economy. If the steel connecting wall member to be inserted into the joint is provided with a projection on the opposite side of the joint to ensure stability during insertion, the width of the steel connecting wall member including the joint and the projection The size corresponding to the result is given.

[0012] The intersecting underground continuous wall may be orthogonal as described in claim 2 or may not be orthogonal. If they are not orthogonal, a steel continuous wall member for the intersection having a shape corresponding to the angle at which the underground continuous wall intersects is prepared.

The widening wall is constructed by circulating an endless chain equipped with a cutting blade on which an underground continuous wall has been constructed, and traversing the cutter post while inserting it into the ground in the width direction of the underground continuous wall. It is also possible to repeat the process by shifting the cutting blade of the endless chain as described in claim 4 once to a wide-width cutting blade having a large distance between both ends in the width direction. Since the widened wall can be constructed by one traversing of the cutter post without raising the floor to the ground, construction efficiency is improved.

The steel connecting wall member according to claim 5, wherein the steel connecting wall member is inserted into the widening wall so that the steel connecting wall member is not inserted while crushing the hardened soil cement from the viewpoint of workability. This is done before the hardening of the wide-walled soil cement. If the widening wall has a length that allows the insertion of two steel connecting wall members, from the viewpoint of securing the verticality and easy insertion of the steel connecting wall member inserted at the intersection, Alternatively, in order to easily position the steel continuous wall member in two directions, the steel continuous wall member is inserted on the opposite side of the widened wall near the intersection in the widened wall, and then connected thereto. 2 at the intersection as
A steel connecting wall member for a crossing portion having a joint portion in a direction is inserted.

In particular, the construction of the underground continuous wall in the direction intersecting with the widening wall and the insertion of the steel continuous wall member into the underground continuous wall as described in claim 7 are performed from the middle of the entire length thereof. If the construction is performed toward the widening wall side, the construction of the underground continuous wall to be constructed later is started even when the underground continuous wall intersects in an L-shape or turns around in a box shape, and reaches the intersection. At this point, the situation in which the soil cement at the intersection of the preceding underground diaphragm wall has hardened can be avoided.

As a result, when the steel continuous wall member is inserted into the underground continuous wall in the direction intersecting with the widening wall, and the steel continuous wall member is connected to the steel continuous wall member at the intersection, the steel inserted into the intersection is used. There is no need to crush soil cement around the joint part of the continuous wall member, and the steel continuous wall member inserted at the intersection and the steel continuous wall member connected to it can be easily connected. become.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 and 2, the present invention relates to an intersection 30 between two underground continuous walls 1 and 2 which intersect each other.
, The underground continuous wall 1 in one of two intersecting directions
To the vicinity of the underground continuous wall 2 in the other direction,
This is a method of constructing a widened wall 3 continuous with the underground continuous wall 1 and having a wall thickness larger than the wall thickness up to a position where the widened wall 3 intersects the underground continuous wall 2 in another direction.

The underground continuous wall 1 has a cutting blade 6 as shown in FIG.
While circulating the endless chain 7 having the shape around the cutter post 8, the cutter post 8 is traversed while being inserted into the ground, and at the same time, a predetermined concentration of cement milk or the like is fed from the lower end of the cutter post 8 or near the ground surface. It is constructed by discharging an injecting liquid such as a solidifying liquid, a water-soluble liquid containing clay such as bentonite, or a low-concentration solidifying liquid.

A water-soluble liquid containing bentonite or the like or a low-concentration solidified material liquid is excavated soil before the steel continuous wall members 4 and 5 are inserted into the underground continuous wall 1 or the widened wall 3. However, since the underground continuous wall 1 and the widened wall 3 need to be hardened after the steel continuous wall members 4 and 5 are inserted, the mixture is used before the steel continuous wall members 4 and 5 are inserted. Is replaced with a solidifying material liquid for soil cement construction, and stirring and mixing are performed.

The cutter post 8 traverses by moving the cutter post 8 along the gantry 11 with respect to the construction device 9 as the hydraulic cylinder 10 provided between the construction device 9 and the cutter post 8 extends.

After the cutter post 8 has moved to the front end in the traveling direction of the construction device 9, the discharge of the injection liquid is stopped, and the cutter post 8 is inserted into the ground while the cutter post 8 is inserted into the ground.
While the construction device 9 is being moved by the traveling device 12 such as a crawler, the hydraulic cylinder 10 is contracted to return to a state where the hydraulic cylinder 10 has been moved to the rear end in the traveling direction. The discharge of the injection liquid is started again, and the cutter post 8 traverses by extending the hydraulic cylinder 10. The underground continuous wall 1 is constructed by repeating the traverse of the cutter post 8 and the movement of the construction device 9.

When the liquid to be injected is discharged from the lower end of the cutter post 8, as shown in FIG. 7, the lower end of the cutter post 8 is formed through a supply path 13 formed in the cutter post 8 in the axial direction or attached thereto. It is discharged from the discharge port 14. The endless chain 7 is stretched between a driving roller 15 and an idle roller 16 and circulates around the cutter post 8 in any direction by the rotation of the driving roller 15.

The construction of the underground continuous wall 1 by the endless chain 7 to which the cutting blades 6 are attached is performed as shown in FIG.
At the point where the section has been entered, the widening wall 3 is constructed by the same cutting blade 6, or the cutting blade 6 is set to have a larger distance between both ends in the width direction as shown in FIGS. The widening wall 3 is constructed in place of the widening cutting blade 60.

The wall thickness of the widening wall 3 is determined by the width and composition of the steel continuous wall member 5 inserted into the intersection 30, and the shape of the joints 5a and 5b. The distance between both ends in the width direction of the widened cutting blade 60 to be replaced is arbitrarily set.

When the widening wall 3 is to be constructed with the original cutting blade 6 mounted, the cutter post 8 is reciprocated in the entire section of the widening wall 3 while being shifted in the width direction as shown by the two-dot chain line in FIG. Thereby, the widening wall 3 is constructed.

When replacing the cutting blade 6 with the widened cutting blade 60,
at the construction start position of the widened wall 3 as shown in (c), or
As shown by the two-dot chain line in (c), the cutting blade 6 is replaced with the widened cutting blade 60 at the construction end position of the widened wall 3.

When replacing the cutting blade 60 with the widened cutting blade 60,
Until the insertion of the steel continuous wall member 5 is performed, or the steel continuous wall member 4 is inserted into the underground continuous wall 2 in the cross direction connected to the steel continuous wall member 5. Until the point
In order to prevent the hardening of the widening wall 3 from starting, the solidifying material liquid is switched to a water-soluble liquid mixed with clay such as bentonite or a low-concentration solidifying material liquid, and the underground indicated by broken lines in (c) and (d). The concentration of the solidified material on the widened wall 3 side is reduced from the boundary between the continuous wall 1 and the widened wall 3.

The work from the end of the insertion of the steel continuous wall member 5 into the intersection 30 to the insertion of the steel continuous wall member 4 connected thereto is completed within a time period in which hardening of the widening wall 3 does not start. In such a case, the widening wall 3 may be constructed while the discharge of the solidifying material liquid is continued from the time of constructing the underground continuous wall 1 without switching the discharge of the solidifying material liquid to the bentonite liquid or the like.

The replacement of the cutting blades 6 with the widened cutting blades 60 is performed by changing the cutting blades 6 on the part of the endless chain 7 that extend above the ground.
Done for After the replacement, the construction of the widened wall 3 is started by moving the cutter post 8 forward in the traveling direction while circulating the endless chain 7.

When the widened cutting blade 60 located at the head in the direction in which the endless chain 7 circulates reaches the deepest part in the ground,
The remaining cutting blades 6 on the ground are replaced with widened cutting blades 60, and the endless chain 7 is circulated in the reverse direction, and the cutter post 8 is traversed backward in the traveling direction to stir and mix with the injection liquid. The widening wall 3 in which the above has been sufficiently performed is constructed.

When the widened cutting blade 60 first exchanged passes through the deepest part of the ground and comes out on the ground, there is no need to further circulate the endless chain 7 in that direction. And the cutter post 8 is also traversed in the opposite direction.

In order to visually confirm that the widened cutting blade 60 that has been replaced first has come out of the ground, it is necessary to widen the blade to the cutter post 8 as shown in FIG. The limit switch 18 that contacts or locks the cutting blade 60 and switches the rotation direction of the drive roller 15
Is attached. When the cover 19 is attached to the upper end of the cutter post 8 to protect the driving roller 15 and the widened cutting blade 60 after replacement may collide with the cover 19, Also limit switch
A reverse rotation of the drive roller 15 by 18 is required.

As shown in FIGS. 2 and 3, after the widening wall 3 is constructed by the widening cutting blade 60, the steel continuous wall members 4, 5 are inserted into the widening wall 3 before the soil cement is hardened. Intersection 30
The steel connecting wall member 4 inserted into the other part has an H-shaped cross section, and joints 4a, 4b for connection with the adjacent steel connecting wall members 4, 5 are formed on both sides in the width direction. .

In inserting the steel connecting wall members 4 and 5 into the widening wall 3, the steel connecting wall member 4 having the joints 4a and 4b on both sides in the width direction is inserted first, and the joint 4b is used as a guide. It is preferable to insert the steel continuous wall member 5 at the intersection 30.

The steel connecting wall member 5 at the intersection 30 is inserted later because the steel connecting wall member 5 shown in FIG. 3 is asymmetrical in both the width direction and the forming direction. This is because it is sometimes difficult to maintain balance and to secure verticality. If the joint portion 4b of the steel connecting wall member 4 inserted in advance is used as a guide and the joint portion 5a is fitted thereto and the steel connecting wall member 5 is inserted, the stability at the time of insertion and the vertical It becomes possible to insert while ensuring the performance.

The steel connecting wall member 5 inserted into the intersection 30 is a steel connecting wall member 4 inserted into the widening wall 3 and a steel connecting wall inserted into the intersecting underground continuous wall 2. Joint portions 5a and 5b are formed on each of the members 4 side. In the drawing, the joint part in two directions
Although the main body of the steel continuous wall member 5 has a box-shaped cross section because of the provision of 5a and 5b, it may be formed into an H-shaped cross section or other shapes.

The joints 4b, 4a, 4b, 5a, 5b, 4a of the steel connecting wall members 4, 5 connected to each other are connected by fitting or engagement, so that one of the joints 4b, 5b is connected. In the case of a concave shape (female), the other joint portions 4a and 5a are combined so as to have a convex shape (male), so that the joint portions 4a and 4b of the steel continuous wall members 4 and 5, 5a, 5b are concave on both sides,
Alternatively, in addition to the case of a convex shape, there is a case where one is a concave shape and the other is a convex shape.

In the widened wall 3, as shown in FIG. 4, as described above, from the viewpoint of securing the stability when the steel continuous wall member 5 is inserted, it is closer to the underground continuous wall 1 that was previously constructed. The steel connecting wall member 4 serving as a reference for inserting the steel connecting wall member 5 at the intersection is inserted, and then the steel connecting wall member 5 is inserted into the intersection 30. In that case, construction is performed in the order of →→→ shown in FIG.

In the case where the steel connecting wall members 5 are symmetrical in the width direction or the forming direction, for example, and the stability at the time of insertion alone can be ensured, the order of insertion of the steel connecting wall members 4 and 5 does not matter. In the case of FIG. 4 where the construction is performed in the order of →→→
The construction may be performed in the order of →→→. Irrespective of the stability at the time of insertion, in order to position the steel continuous wall members 4 and 5 in order to refer to the steel continuous wall member 5 of the intersection 30, the steel continuous wall member 5 is used. It may be inserted earlier.

The steel continuous wall member 5 inserted into the intersection 30
The joint 5b on the underground continuous wall 2 side to be constructed later is the widened wall 3.
Is formed at a position along the boundary of the cross section, and serves as a clue for positioning when the steel continuous wall member 5 is inserted.
In order to facilitate positioning of the steel continuous wall member 5 when the steel continuous wall member 5 inserted into the 30 is inserted into the widening wall 3,
As shown in FIG. 4, a projection 5c is formed along the boundary of the widened wall 3 also on the opposite side of the joint 5b on the underground continuous wall 2 side to be constructed later.

After inserting the steel continuous wall members 4 and 5 into the underground continuous wall 1 including the widened wall 3, the widened cutting blade 60 for constructing the widened wall 3 is replaced with the cutting blade 6 for constructing the underground continuous wall 2. Exchange, the underground continuous wall 2 in the direction intersecting with the constructed underground continuous wall 1 is constructed,
The steel continuous wall member 4 is inserted. 4, the arrow on the underground continuous wall 2 indicates the order of insertion of the steel continuous wall member 4.

When the construction device 9 is moved, the cutter post 8 is pulled up along the leader 17 while the endless chain 7 is mounted, is cut off in the axial direction, and the cutter post 8 separated from the construction device 12 is moved to the next construction site. Then, the cutter post 8 which has been divided again is supported by the leader 17 while assembling.

When the underground continuous walls 1 and 2 intersect in an L shape or wrap around in a box shape to form an underground structure, construction of the underground continuous wall 2 to be constructed later is started. In order to avoid the situation where the soil cement at the intersection 30 or the widening wall 3 is hardened at the time of reaching the intersection 30 of the preceding underground continuous wall 1, the underground in the direction intersecting the widening wall 3 is necessary. Continuous wall 2
Is constructed from the middle of the entire length toward the widening wall 3 side. When the underground continuous walls 1 and 2 are made to go around in a box shape, they are generally constructed in a procedure as shown in FIG. 5, for example.

If the construction is performed according to the procedure shown in FIG. 5, before the soil cement is hardened at the intersection 30, the insertion of the steel continuous wall member 4 into the underground continuous wall 2 to be constructed later can be completed. Therefore, it is not necessary to drop the steel continuous wall member 4 connected thereto while crushing the soil cement around the joint 5b on the underground continuous wall 2 side of the steel continuous wall member 5 at the intersection 30. Section 5 steel wall member 5 and underground continuous wall 2
Can be easily connected to the steel continuous wall member 4.

[0045]

The underground continuous wall in one of the two intersecting directions is constructed up to the intersection with the underground continuous wall in the other direction, and then connected to the underground continuous wall. In order to construct a widened wall with a wall thickness greater than the thickness to a position where it intersects the underground continuous wall in the other direction, it becomes possible to insert a steel continuous wall member having joints in two directions at the intersection, The steel continuous wall member can be connected in any direction, and the steel continuous wall member can be easily arranged at the center of the wall thickness.

In the fourth aspect, since a part of the cutting blade of the endless chain is temporarily replaced with a widened cutting blade having a large distance between both ends in the width direction, the cutter post is not pulled up to the ground, and the cutter post is traversed only once. The widening wall can be constructed by this, and the construction efficiency increases.

In the seventh aspect, the construction of the underground continuous wall in the direction intersecting with the widened wall and the insertion of the steel continuous wall member into the underground continuous wall are performed from the middle of the entire length toward the widened wall side. To start the construction of the underground diaphragm wall to be constructed later, and to avoid the situation where the soil cement at the intersection of the preceding underground diaphragm wall has hardened when reaching the intersection It is possible to easily connect the steel continuous wall member inserted into the intersection and the steel continuous wall member connected thereto.

[Brief description of the drawings]

1 (a) to 1 (d) are plan views showing construction procedures from an underground continuous wall to a widened wall.

FIG. 2 is a plan view showing a state where the construction of the widening wall is completed.

FIG. 3 is a plan view showing a state where a steel continuous wall member is inserted into a widening wall.

FIG. 4 is a plan view showing a procedure of inserting a steel continuous wall member into an underground continuous wall in two directions.

FIG. 5 is a plan view showing a construction procedure when the underground continuous wall goes around in a box shape.

FIG. 6 is an elevation view showing a construction apparatus and a state of underground continuous wall construction.

FIG. 7 is an elevational view showing a lower end portion of the cutter post.

FIG. 8 is an elevational view showing how a limit switch is mounted.

FIG. 9 is a plan view showing an arrangement state of a conventional steel continuous wall member.

[Explanation of symbols]

1,2 ... Underground wall, 3 ... Walling wall, 30 ... Intersection,
4 ... steel connecting wall member, 4a, 4b ... joint, 5 ... steel connecting wall member, 5a, 5b ... joint, 5c ... projection, 6 ... cutting blade, 60 ... wide cutting Blade, 7 Endless chain, 8 Cutter post, 9 Construction equipment, 10 Hydraulic cylinder,
11 ... stand, 12 ... traveling device, 13 ... supply path, 14 ... discharge port, 15 ... drive roller, 16 ... idle roller, 17 ...
... leader, 18 ... limit switch, 19 ... cover.

Claims (7)

[Claims] An endless chain having a cutting blade is circulated around a cutter post at the intersection of two underground continuous walls intersecting with each other, while the cutter post is traversed while being inserted into the ground, Injected liquid is discharged from the lower end of the cutter post or near the ground surface, and an underground continuous wall in one of the two intersecting directions is built up to near the intersection with the underground continuous wall in the other direction. Later, a widened wall that is continuous with the underground continuous wall and has a wall thickness larger than the wall thickness is
A method of constructing an underground continuous wall intersection that is built up to a position where it intersects with another underground continuous wall. 2. The method according to claim 1, wherein the underground continuous walls in two directions are orthogonal to each other. 3. The widened wall is inserted at the intersection with the underground continuous wall in another direction, and has a width large enough to insert a steel continuous wall member having a joint in two directions. Or the method of constructing an underground continuous wall intersection according to claim 2. 4. When the underground continuous wall in one direction is constructed up to near the intersection with the underground continuous wall in the other direction, a part of the cutting blades of the endless chain is temporarily set to a distance between both ends in the width direction. The construction method of an underground continuous wall intersection according to any one of claims 1 to 3, wherein the widened wall is constructed by replacing with a large widened cutting blade. 5. A steel connecting wall member having joints in two directions before the hardening thereof is inserted into an intersection of the widened wall and the underground continuous wall in another direction. Construction method of the underground continuous wall intersection described in Crab. 6. A steel continuous wall member is inserted into the widened wall on the side opposite to the intersection with the underground continuous wall in the other direction, and then the joint is connected to the intersection in two directions so as to be connected thereto. The method for constructing an underground continuous wall intersection according to claim 5, wherein a steel continuous wall member having: 7. Construction of an underground continuous wall in a direction intersecting with the widening wall and insertion of a steel continuous wall member into the underground continuous wall from the middle of the entire length toward the widening wall side. The construction method of an underground continuous wall intersection according to claim 5 or claim 6.