JPH0370050B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a construction method for an underground continuous wall, and in particular, an underground continuous wall that can strengthen the connection between panels by introducing prestress between the panels formed by pouring concrete. This relates to the panel-to-panel joining method.

Conventionally, when constructing an underground structure, etc., an underground continuous wall for earth retention is constructed along the outer wall of the structure, and the inside of the wall is excavated to construct the underground structure. It was.

In this case, the above-mentioned underground continuous wall is usually constructed by excavating a narrow vertical trench with a rectangular plane from the ground, suspending a reinforcing bar cage into the trench, and then pouring concrete into the trench. A leading panel is formed by solidifying the leading panel, and then trailing panels connected in the longitudinal direction of the leading panel are successively connected and formed in the same manner as the preceding panel to obtain a predetermined underground continuous wall. It was hot.

However, constructing an underground continuous wall using this construction method had the following drawbacks.

In other words, the joints between the panels cannot ensure sufficient strength to withstand surrounding soil water pressure, earthquakes, etc. by joining concrete together. For this reason,
In order to reinforce the joint, methods have been proposed in which the joint between the preceding panel and the succeeding panel is formed into a concave-convex fit, or a method in which reinforcing reinforcing bars are inserted into the joint.

However, even in such a construction method, although the strength of the joint is reinforced to some extent, it is still far from ensuring the desired strength.

This invention was made in view of the above circumstances, and its purpose is to make the joint between constructed panels extremely strong by introducing prestress into the joint between the constructed panels. Our goal is to provide construction methods.

In order to achieve this object, the present invention has developed an underground continuous wall by excavating a vertical trench with a narrow plane rectangular shape from the ground, suspending a reinforcing bar cage into the vertical trench, and then pouring and hardening concrete. In the construction method, the vertical groove is composed of a plurality of leading panel vertical grooves excavated at predetermined intervals and a plurality of trailing panel vertical grooves provided between these leading panel vertical grooves. At the same time, the reinforcing bar cage has a pair of partition plates fixedly installed at both longitudinal ends thereof so as to intersect with the longitudinal direction of the longitudinal groove, and extends in the vertical direction of the longitudinal groove, and one end of the reinforcing bar cage is attached to the partition plate. the other end is open on the inner surface side of the underground continuous wall to be constructed, and a removable filling is inserted at both ends,
It has a plurality of hollow cylindrical sheaths arranged in multiple stages at intervals in the vertical direction, and after each of the reinforcing bar cages is suspended in the longitudinal groove for the preceding panel, the partition plate and the After backfilling the space defined by the longitudinal end face of the longitudinal groove for the preceding panel, concrete is poured between the partition plates of the reinforcing bar cage and allowed to harden to form a preceding panel group, and then A vertical groove for the trailing panel is excavated between the leading panels, and the reinforcing bar cage is suspended in this groove to allow the adjacent sheaths to communicate with each other. After that, concrete is installed in the trailing panel vertical groove. to form a trailing panel joined to the preceding panel to construct a continuous underground wall, and as the interior of the underground wall is excavated, the filling in the sheath is exposed sequentially from the upper side. Then, by inserting a prestressing steel material into the sheath and tensioning it, excavation is performed while introducing prestress between the adjacent preceding and following panels.

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

FIGS. 1 and 2 show an embodiment of the method for joining panels of an underground continuous wall according to the present invention.

The joining method shown in the figure is one in which the present invention is applied when constructing an underground continuous wall in a slightly curved state.

First, as shown in Fig. 1a, in a predetermined place where an underground continuous wall is to be constructed, narrow vertical grooves 10 for the preceding panel, which are rectangular in plan, are excavated from the ground at predetermined intervals, and In the vertical groove 10 for the panel, the second
A reinforcing bar cage 12 as shown in the figure is suspended, and the reinforcing bar cage 12 shown in the figure is formed to have an outer shape having approximately the same width, the same length, and the same height as the vertical groove 10 for the preceding panel. , flat plate-shaped partition plates 14a-14a extending in the vertical direction are fixed to the longitudinal ends by welding to ordinary reinforcing bars 16 at appropriate locations, and the partition plates 14a-1
4a is adapted to be oblique to the longitudinal direction of the preceding panel vertical groove 10, as shown in FIG. 1b, when suspended in the preceding panel vertical groove 10. A substantially triangular space 18 is defined by the longitudinal end face of the vertical groove 10 and the partition plates 14a-14a.

Further, in the vertical direction of the reinforcing bar cage 12, hollow cylindrical sheaths 20a with slightly bent interiors are arranged in multiple stages at predetermined intervals, and each sheath 20a...
One end of a is opened through the partition plates 14a-14a, and the other end is opened when a preceding panel is formed by pouring concrete between the partition plates 14a-14a, as described later. It is arranged to open into the inner wall of the panel. A removable filler such as a sponge is placed at both ends of each cylindrical sheath 20a to prevent concrete from entering the sheath 20a and blocking it when concrete is poured. has been inserted.

When the reinforcing bar basket 12 with the above structure is suspended in the preceding panel vertical groove 10, as shown in FIG. The shaped space 18... is backfilled with excavable earth and sand, and then concrete is poured between the partition plates 14a and 14a arranged at both ends of the reinforcing bar cage 12... to solidify it. As a result, the preceding panels 22... are formed.

Next, as shown in FIG. 1c, each part between the leading panels 22 is excavated into a rectangular shape in plan view to form a trailing panel vertical groove 24. 24...Inside, the above-mentioned reinforcing bar cage 1
Same structure as 2, partition plates 14a-14a,
The reinforcing bar cage 12'... in which the sheaths 20b... arranged in multiple stages are placed inside the preceding panel 22... 20b so that adjacent parts communicate with each other, concrete is poured into the longitudinal groove 24 for the trailing panel and hardened, as shown in FIG. 1d. A predetermined underground continuous wall is constructed in which the panels 22... and the trailing panels 28... are connected in the longitudinal direction.

Next, the interior surrounded by the underground continuous wall is excavated, but in this case, the excavation proceeds from the ground,
When the ends of the sheaths 20a, 20b located at the uppermost stage are exposed, the filling inserted into the ends of the sheaths 20a, 20b is removed, and the sheaths 2
A prestressing steel plate is inserted into 0a and 20b and tensioned using a fixing tool to introduce prestress between adjacent panels.

This prestress introduction work is performed each time the sheaths 20a, 20b are exposed as the excavation stage progresses.

The sheaths 20a arranged in multiple stages and adjacent to each other
..., 20b... are connected to the sheath 20a...,
Since one end of 20b... is fixedly fixed through the flat partition plates 14a, 14a as described above, when assembling them into the respective reinforcing bar cages 12, 12', vertical and horizontal By fixing the reinforcing bar cage 12' with high precision in the direction, when the reinforcing bar cage 12' for the trailing panel is hung, the upper ends of the partition plates 14a-14a of the preceding panels 22... and the partition plates 14b-14b of this reinforcing bar cage 12' This can be done relatively easily by matching the top edges of the .

Now, if an underground continuous wall is constructed with the above-mentioned configuration, it becomes possible to introduce prestress between the adjacent leading and trailing panels 22, 28, etc., and the joint state of the underground continuous wall can be controlled. It can be made extremely strong.

In addition, by introducing prestressing force into the underground continuous wall, the amount of ordinary reinforcing bars can be significantly reduced compared to when constructed using conventional construction methods.

Furthermore, being able to introduce prestress as excavation is carried out has the advantage of being able to follow changes in surrounding conditions.

FIG. 3 shows another embodiment of the present invention, and the feature point is that the above embodiment has two adjacent panels
2..., 28... Multi-tiered sheath 2 disposed between
0a..., 20b... are arranged at the same level in the horizontal direction, whereas in the figure a they are arranged at different levels at the adjacent joints, and in the figure b the preceding panel 22 Sheath 2 buried inside
The length of the sheath 20b embedded in the trailing panel 28 is different from the length of the sheath 20b.

In this way, the prestress introducing sheath 20a...
By arranging ..., 20b... in various combinations,
It becomes possible to construct the most advantageous continuous wall that matches the conditions such as the geology of the surrounding area where the underground continuous wall is constructed.

FIG. 4 shows another example of the reinforcing bar basket used in carrying out the present invention. In the above embodiment, flat partition plates 14 are fixed to both ends of the reinforcing bar cage.
The sheaths 20a and 20b are extended so as to be close to each other along the inner surface so that the cross section is approximately L-shaped, and both ends of the sheaths 20a and 20b are fixed to this partition plate. It is more desirable to use a reinforcing bar cage as shown in the figure because it prevents the sheaths 20a and 20b from shifting when pouring concrete for forming panels.

In addition, although the above-mentioned example illustrates the case where the present invention is applied when constructing a curved underground continuous wall, the present invention can also be applied to a straight underground continuous wall.

As explained in detail in the examples above, when constructing an underground continuous wall using the construction method of the present invention, prestress is introduced between adjacent panels as internal excavation work progresses. The joint condition becomes extremely strong, making it possible to reduce the amount of ordinary reinforcing bars buried in the wall.

[Brief explanation of drawings]

Figures 1 and 2 show an embodiment of the method for joining panels of an underground continuous wall according to the present invention. Figure 1 is a plan view showing the order of the steps, and the steps are sequentially a to FIG. 2 is a perspective view of the rebar cage. FIG. 3 shows another embodiment of the present invention, and FIGS. 3a and 3b are schematic front views of each. FIG. 4 is a perspective view showing another example of a reinforcing bar cage used in carrying out the present invention. 10... Vertical groove for preceding panel, 12... Rebar cage,
12'...Reinforced cage, 14a, b...Partition plate,
16... Ordinary reinforcing bar, 18... Space, 20a, b
... sheath, 22 ... leading panel, 24 ... longitudinal groove for trailing panel, 28 ... trailing panel.

Claims (1)

[Claims of Claims] 1. A method of constructing an underground continuous wall by excavating a narrow vertical rectangular groove from the ground, suspending a reinforcing bar cage into the vertical groove, and then pouring and hardening concrete. In the method, the vertical groove is composed of a plurality of leading panel vertical grooves excavated at predetermined intervals, and a plurality of trailing panel vertical grooves provided between these leading panel vertical grooves, The rebar cage is
A pair of partition plates are fixedly installed at both ends of the longitudinal direction so as to intersect with the longitudinal direction of the longitudinal groove and extend in the vertical direction of the longitudinal groove, one end of which is opened in the partition plate, and the other end is constructed. It has a plurality of hollow cylindrical sheaths that are open on the inner surface of the underground continuous wall, have removable filling inserted at both ends, and are arranged in multiple stages at intervals in the vertical direction. , after each of the reinforcing bar cages is suspended in the preceding panel longitudinal groove, and after backfilling the space defined by the partition plate and the longitudinal end surface of the preceding panel longitudinal groove, the reinforcing bar cage is After forming a preceding panel group by pouring and hardening concrete between the partition plates, a vertical groove for the following panel is excavated between adjacent preceding panels, and the reinforcing bar cage is suspended in this groove. After making the adjacent sheaths communicate with each other, concrete is poured into the longitudinal groove of the trailing panel to form a trailing panel joined to the leading panel to construct a continuous underground wall. Then, as the inside of the underground wall is excavated, the filling material in the sheath that is exposed from the upper stage side is removed, and a prestressing steel material is inserted into the sheath and tensioned, so that the adjacent An inter-panel joining method for an underground continuous wall, which is characterized by excavating while introducing prestress between the leading and trailing panels. 2. The underground structure according to claim 1, wherein the partition plate of the reinforcing bar cage is fixed so as to be oblique to the longitudinal direction of the vertical groove, and the space portion is formed into a substantially triangular shape. Connection method between panels for continuous walls.