JP3567393B2 - Underground diaphragm wall - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an underground continuous wall constructed in the ground when constructing an underground structure.
[0002]
[Prior art]
Some underground structures, such as underground tanks, receive the buoyancy of groundwater on the side walls and bottom plate. This type of underground structure has a structure for preventing the buoyancy of the building from rising.
[0003]
As an example, FIG. 2 shows an underground structure T constructed in the ground G. The underground continuous wall 1 is constructed around a construction area in the ground G for the purpose of retaining the ground and stopping water. Inside the underground continuous wall 1, a side wall 2 constituting an underground structure T, Bottom plate 3 has been constructed. Inside the underground continuous wall 1, a sheath tube 4 opening toward the side wall 2 is buried, and a slip bar 5 is inserted into the sheath tube 4 so as to project toward the underground structure T side. Furthermore, the underground continuous wall 1 and the side wall 2 are connected by burying the slip bar 5 projecting toward the underground structure T in the side wall 2.
[0004]
In this underground structure T, when the buoyancy of the groundwater acts on the bottom plate 3, the force is transmitted to the underground continuous wall 1 via the slip bar 5, so that the underground structure T and the underground continuous wall 1 are connected. The weight increases as a whole, and the buoyancy of the building is prevented against the buoyancy of groundwater. Further, when an ultra-low temperature material such as LNG is stored, a phenomenon occurs in which the side wall 2 tries to shrink inside the underground structure T, but the side wall 2 is not directly connected to the underground continuous wall 1 and the slip bar 5 is free to be displaced in the axial direction, so that contraction is possible without being restricted by the underground continuous wall 1.
[0005]
By the way, as a construction procedure of the underground continuous wall 1, first, a digging groove 6 is dug along the construction area, and the digging groove 6 is filled with water in order to prevent collapse of the digging groove 6 due to groundwater pressure. A method is adopted in which a steel cage 7 shown in FIG. 3 is built and concrete is gradually poured from the bottom of the excavation groove 6. A plurality of spacers 8 are fixed to the reinforcing bar 7 used here at a distance from the surface facing the wall surface of the excavation groove 6. The spacer 8 is a trapezoidal shape in which both ends of a plate-shaped steel plate are bent in a hook shape, and the height of the central portion is processed according to the size of the cover, and is welded to the reinforcing bar cage 7. Since a gap is secured between the wall surface of the excavation groove 6 and the reinforcing bar 7 by the spacer 8, an appropriate covering is formed on the underground continuous wall 1 when concrete is poured.
[0006]
[Problems to be solved by the invention]
However, there are the following problems when constructing the underground continuous wall 1 according to the above procedure.
{Circle around (1)} When the reinforcing cage 7 is built into the excavation groove 6, the spacer 8 may cut the wall surface of the excavation groove 6, and the side surface of the underground continuous wall 1 may not be formed smoothly.
{Circle around (2)} In the case where connecting means for connecting to the underground structure T is provided on the underground continuous wall 1, if these connecting means are prepared in advance in the reinforcing steel cage 7 and then erected in the excavation groove 6, the reinforcing steel cage 7 is provided. There is a possibility that the connecting means charged into the groove may rub against the wall surface of the excavation groove 6, and the installation angle and the installation position may be shifted.
{Circle around (3)} Similarly, in the case where the connecting means with the underground structure T is provided on the underground continuous wall 1, the underground continuous wall 1 is constructed, the underground structure T is excavated and the underground continuous wall 1 is excavated. If an attempt is made to install the connecting means by drilling or the like, the connecting means may not be able to be installed at an appropriate position by hitting the spacer 8 or the reinforcing bar 7.
[0007]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an underground continuous wall having high workability at the time of construction and a good finish at the time of completion.
[0008]
[Means for Solving the Problems]
The underground continuous wall according to claim 1, wherein a reinforcing steel cage is built in an excavation groove provided in the ground and concrete is poured into the excavation groove, and the reinforcing steel cage is a wall surface of the excavation groove. The spacer extends vertically along the reinforcing bar, is approximately equal to the vertical length of the reinforcing bar, and has a predetermined space between the reinforcing bar and the reinforcing bar. It consists of a plate-shaped part arranged at intervals and a support part supporting the plate-shaped part from the plate-shaped part by standing on a steel cage, and the plate-shaped part has an underground structure constructed in close proximity It is characterized in that a plurality of sheaths are provided in which connecting means interposed between the side walls of the object are inserted and arranged .
[0009]
The underground continuous wall described in claim 2 is characterized in that the lower end of the plate-like portion of the spacer in the underground continuous wall described in claim 1 has a shape that is warped toward the reinforcing bar cage.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the underground continuous wall according to the present invention will be described with reference to FIG.
FIG. 1 shows a reinforced cage 11 constituting an underground continuous wall. The reinforcing bar cage 11 serves as a skeleton inside the underground continuous wall, and is formed in a cage shape by combining reinforcing bars in a lattice shape. The outer shape is almost the same as the outer shape of the underground continuous wall to be constructed, but is generally smaller than the underground continuous wall so that a concrete cover is formed around the reinforcing bar.
[0012]
A plurality of spacers 12 are provided on the side surface of the reinforcing bar cage 11 forming the wall surface of the underground continuous wall to secure a gap corresponding to a cover between the reinforcing bar combined in a lattice shape and the wall surface of the excavation groove. Have been.
[0013]
The spacer 12 includes a plate-like portion 12a extending vertically along the reinforcing bar 11 and a support portion 12b which stands on the reinforcing bar 11 from the plate-like portion 12a and supports the plate-like portion 12a.
[0014]
The plate-shaped portion 12a is a long member that is substantially equal to the length of the reinforcing bar 11 in the vertical direction, and its lower end 12c has a shape warped toward the reinforcing bar 11 like a sled, and is close to the tip. The width is formed to be narrower.
[0015]
The support portions 12b are provided integrally with the plate portion 12a, and a plurality of support portions 12b are provided at regular intervals in the longitudinal direction of the plate portion 12a. The support portion 12b is formed as a pair protruding from both sides of the plate-like portion 12a, and both are bent in a hook shape toward the reinforcing bar 11 to form a trapezoidal shape. And fixed by welding. At this time, the height from the lower end of the support portion 12b to the plate-like portion 12a is processed in accordance with the size of the concrete cover, and the interval between the plate-like portion 12a and the reinforcing bar 11 is the size of the concrete cover. It is almost equal to.
[0016]
In the plate-like portion 12a, a sheath tube 13 into which a slip bar (connection means) 5 interposed between the underground structure T and the side wall 2 constructed close to the underground continuous wall is inserted. A plurality is provided. The sheath tube 13 is welded by aligning the opening end of the sheath tube 13 from the reinforcing bar 11 side with the through hole 12d provided in the length direction of the plate-shaped portion 12a, that is, the vertical direction of the reinforcing bar 11 from the reinforcing bar 11 side. Fixed.
[0017]
Further, a plurality of separator inserts 14 to which a separator 9 stretched between the underground continuous wall and the side wall 2 is mounted on the plate-shaped portion 12a. The separator insert 14 is fixed at a position different from the sheath tube 13 to the plate-like portion 12a by welding in the same manner as the sheath tube 13, and in addition, the extension reinforcing bar 15 is welded to the reinforcing bar 11 to be more firmly fixed. I have.
[0018]
A procedure for constructing an underground continuous wall using the above-described reinforcing cage 11 will be described. First, an excavation groove 6 of a predetermined size is provided in the ground G, and after filling the excavation groove 6 with water, the reinforcing bar cage 11 is built while the spacers 12 are along the wall surface of the excavation groove 6. A lid is attached to the sheath 13 and the separator insert 14 fixed to the spacer 12 so that earth and sand or concrete does not flow into the inside. Then, concrete is poured into the excavation trench 6 to construct an underground continuous wall.
[0019]
When the underground continuous wall is completed, the construction area of the underground structure T is excavated, the lid attached to the spacer 12 is removed, the sheath tube 13 and the separator insert 14 are opened, and the side wall is attached while the slip bar 5 and the separator 9 are attached. Proceed with the construction of 2.
[0020]
According to the underground continuous wall constructed as described above, when the reinforcing bar cage 11 is built, the plate-like portion 12a of the spacer 12 that is in contact with the wall surface of the excavation groove 6 extends in the vertical direction of the reinforcing bar cage 11. In addition, since the lower end 12c is curved inward of the reinforced cage 11, the spacer 12 does not move on the wall surface of the excavation groove 6 like a sled, and does not cut the soil on the wall surface. Therefore, the side surface of the underground continuous wall taken into the excavation groove 6 is formed smoothly.
[0021]
Since the sheath tube 13 and the separator insert 14 are arranged between the spacer 12 and the reinforcing bar 11 and are firmly fixed to the spacer 12 by welding, they do not directly hit the wall surface of the excavation groove 6, and The installation angle and the installation position do not shift.
[0022]
In addition, since the sheath tube 13 and the separator insert 14 are previously installed at appropriate positions, the trouble of installing these after the construction of the underground continuous wall is omitted.
[0023]
【The invention's effect】
As described above, according to the underground continuous wall described in claim 1, when the reinforcing cage is built in the excavation groove, the plate-like portion of the spacer in contact with the wall surface of the excavation groove has a vertical direction of the reinforcing cage. When the spacer moves along the wall surface of the excavation groove, the spacer does not cut off the soil on the wall surface, so that no irregularities are formed on the wall surface. Therefore, the side surface of the underground continuous wall formed on the wall surface of the excavation groove can be formed smoothly. In addition, the plate-shaped portion is arranged with a spacing approximately equal to the size of the cover between the reinforcing bar and the supporting portion standing on the reinforcing bar, and concrete is poured into this space, so that the underground Appropriate concrete covering can be formed on both sides of the continuous wall.
In addition, by providing in advance a spacer for inserting the connecting means with the underground structure in the spacer, it is possible to eliminate the work of drilling the wall after constructing the underground continuous wall, The workability related to the construction work of the underground structure can be improved.
[0024]
According to the underground continuous wall described in claim 2, the lower end of the plate-like portion of the spacer has a shape warped toward the rebar cage side, and the plate-like portion is like a sled along the wall surface of the excavation groove. Since the reinforced cage is smoothly inserted into the excavation groove by moving, the workability of the erection work of the reinforced cage can be improved.
[Brief description of the drawings]
FIG. 1 is a plan view showing an embodiment of an underground continuous wall according to the present invention.
FIG. 2 is a side sectional view showing an example of an underground structure constructed in the ground.
FIG. 3 is a perspective view showing an example of a reinforcing bar provided on the underground continuous wall in FIG. 2;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Underground continuous wall 2 Side wall 5 Slip bar 6 Excavation groove 11 Reinforced basket 12 Spacer 12a Plate-like part 12b Support part 13 Sheath pipe 14 Separator insert T Underground structure G Ground

Claims (2)

Reinforcing cages are built in excavation grooves provided in the ground, and underground continuous walls formed by casting concrete in the excavation grooves,
The reinforced cage is provided with a spacer for securing a gap between a wall of the excavation groove,
The spacer extends vertically along the reinforcing bar, is substantially equal to the vertical length of the reinforcing bar, and a plate-shaped portion disposed at a predetermined interval from the reinforcing bar,
And a supporting portion that supports the plate-shaped portion by standing on the reinforcing bar from the plate-shaped portion ,
The underground continuous wall, wherein a plurality of pods are provided in the plate-shaped portion, into which a connecting means interposed between the side wall of the underground structure and the underground structure is inserted and arranged . In the underground continuous wall according to claim 1,
An underground continuous wall, wherein a lower end of a plate-like portion of the spacer is warped toward a reinforcing bar side.

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