JPH08253927A - Joint structure in underground continuous wall - Google Patents

Abstract

PURPOSE: To reduce man-hours for setups and changeover, and enhance work efficiency by fixedly mouniting a seal material on the rear surface on the lower part of a partition board of a hollow box joint installed to a construction joint, and filling up crushed stones thereon and allowing the partition board to be polled easily after the execution of construction joint. CONSTITUTION: A seal material 18 is fixedly applied on the rear surface of the lower part of a partition board 16 which closes an opening surface of a box joint 10 constructed at a set-back position wherein the box joint is installed on the upper part of a construction joint of an underground concrete wall C. During concrete placement of a preceding wall, no concrete is arranged to creep around the rear surface of the partition board 16. Then, a cage is installed in an excavated ditch of a succeeding wall while single particle crushed stones are filled in a set back space on the rear surface of the partition board 16. The seal material 18 is molded in one piece all over the rear surface of the partition board 16, thereby filling of the crushed stones 20 may be omitted. After the lower part of the box joint 10 is cut, pull out resistance is reduced when the partition board 16 is pulled. This construction makes it possible to enhance work efficiency dramatically.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joint structure for a continuous underground wall in which the partition plate provided on the opening surface of a box joint arranged at the upper part of a joint between panels is improved in drawability.

[0002]

2. Description of the Related Art A continuous underground wall is formed by excavating a slot hole in the ground while filling muddy water, repeating the work of placing a rebar cage in the slot hole and then placing concrete. It is a construction method in which the wall bodies are successively spliced in succession.

In this type of construction method, the treatment of the joint portion that secures the rigid connection between the panels has been an important technical subject, and various methods have been proposed in the past. One of them is a hollow box. There is a construction method that provides a body joint.

In this construction method, a box joint is arranged at the splicing end of the rebar cage to prevent the concrete of the preceding panel from creeping in, and it is arranged at the end of the box joint after excavating the trailing panel. By pulling out the partition plate and overlapping the reinforcing bars of the leading and trailing panels within the space of the box joint, the shearing force between the panels is increased.

However, for example, in a continuous underground wall that extends 100 m underground, the weight of the box joint and the weight of the partition plate are extremely heavy, and in particular when the concrete is poured, the concrete wraps around the tip surface of the partition plate and is pulled out. The work becomes extremely difficult.

Therefore, for example, as disclosed in Japanese Examined Patent Publication No. 4-30491, a construction method has been proposed in which the upper half of the panel is rigidly joined by a box joint and the lower half is joined to each other by a cutting joint method. ing.

According to this construction method, the weight of the partition plate is reduced and the partition plate can be easily pulled out, and there is an advantage that not only the waterproof property between the adjacent panels but also the durability against the horizontal component force can be sufficiently secured by the rigid connection by the box joint. .

[0008]

However, when adopting such a construction method, the actual structure of the joint is
In order to secure the cutting allowance in the lower half, conventionally, a partition plate is doubled on the opening surface of the box joint, and the partition plate is placed on the end of the slot after the construction of the preceding panel. After pulling out the partition plate of the above, excavating the trailing slot and cutting the lower half part, pulling out the second partition plate to build the rebar cage and place concrete, so The first partition plate had to be pulled out before excavation of the row panel, which was troublesome for setup change.

[0009] Further, since concrete runs into the first partition plate, the pull-out resistance is not necessarily reduced only by reducing the size of the partition plate. Was becoming.

The present invention is intended to solve the above problems, and an object of the present invention is to reduce the pull-out resistance of the partition plate by adding a simple structure without the trouble of setup change. The present invention provides a joint structure for a continuous underground wall.

[0011]

In order to achieve the above-mentioned object, the invention according to claim 1 is a box which is hollow on the upper side of the joint portion with the trailing panel of the preceding panel which constitutes the underground wall. A joint is arranged, the upper side of the joint portion of the preceding panel and the trailing panel is rigidly connected integrally through the box joint, and the lower side of the joint portion is connected with concrete by a cutting joint. It is a continuous underground wall,
A partition plate which is built into the box joint from the connecting surface opening at a setback position to close the opening surface, and a partition hole integrally formed on the lower part of the front end surface of the partition plate, and the end of the groove of the preceding panel. And a crushed stone filled in a setback space formed between the top surface of the seal material, the upper end surface of the partition plate, and the end of the groove hole of the preceding panel. It is characterized by that.

Further, in the invention according to claim 2, a hollow box joint is arranged on the upper side of the joint portion with the trailing panel of the preceding panel constituting the underground wall, and the hollow box joint is interposed. A continuous underground wall in which the upper side of the joint portion of the preceding panel and the trailing panel is integrally rigidly joined, and the lower side of the joint portion is joined to each other by cutting. In the joint, a partition plate that is installed at the setback position from the connecting surface opening and closes the opening surface, and a seal that is integrally molded on the entire rear surface of the partition plate and that contacts the groove hole end portion of the preceding panel It is characterized by having wood.

[0013]

According to the inventions of claims 1 and 2,
At the time of placing concrete on the preceding panel, the sealing material prevents the concrete from driving into the lower surface side of the partition plate. Immediately after the construction of the preceding panel, excavation of the groove of the succeeding panel and cutting of the lower part of the box joint are performed, then the partition plate is pulled out, and the reinforcing bar cage on the succeeding panel side and the concrete placing work can be performed. it can.

According to the first aspect of the present invention, the lateral pressure of the concrete can be counteracted by the crushed stones filled in the setback space. Since the crushed stones filled in the upper part of the setback space fall naturally during cutting, the pull-out resistance of the partition plate is greatly reduced.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. 1 and 2 show a box joint according to the present invention, and FIGS. 3 (a) to 3 (d) show a construction procedure of a jointing method using the box joint.

The box joint 10 shown in the figure is arranged vertically above the joining side of the rebar cage 12, and is composed of a bottom plate 101 inclined toward the opening side, both side plates 102 and a back plate 103. It has a U-shaped cross section with an open tip,
And the transverse bar of the rebar cage 12 is penetrated and arranged in the inside,
Further, a vertical insertion guide 104 made of a combination of a U-shaped steel plate and an L-shaped steel plate is integrally provided on the inner side slightly behind the open ends of the both side plates 102. It should be noted that the drawing is drawn in a state of being scaled down in the vertical direction.

The rebar cage 12 provided with this box joint 10 is
As shown in FIG. 3 (a), after being inserted into the leading slot 14 a that constitutes the leading panel 14, the insertion guide 1 is inserted.
Partition plate 16 that is vertically guided by inserting both sides into 04
Thus, the opening surface of the box joint 10 is closed.

The partition plate 16 is installed at a position slightly set back from the open ends of the both side plates 102 according to the position of the insertion guide 104, and the sealing material 18 is integrally formed at the lower end surface of the partition plate 16. ing.

The sealing material 18 is a lightweight and elastic material such as fiber-containing mortar, closed-cell urethane foam, and high-density polystyrene foam, and is a material that can dig into the flow pressure of concrete and the weight of crushed stone described later. It is formed of a molded body, is formed to have an inclination corresponding to the inclination of the bottom plate 101, and contacts the insides of the bottom plate 101 and both side plates 102, and is set to a thickness such that the tip end surface contacts the end of the groove hole 14a, The space formed at the end of the slot is vertically partitioned by the sealing material 18.

After the partition plate 16 has been built up as described above, a reaction member made of H-shaped steel (not shown) is inserted into the box joint 10 closed by the partition plate 16 and the rear plate 103 and the partition plate 1 are inserted.
6 against the concrete pouring pressure,
As shown in FIG. 4, if the set-back space on the upper side formed by the top surface of the sealing material 18, the tip surface of the partition plate 16 and the end of the slot is filled with single-grain crushed stones 20 and the space is completely closed, , The joint structure is completed and the concrete is ready for pouring.

After that, concrete C is poured using a tremey pipe or the like and is replaced with muddy water so that each part except the hollow inside of the box joint 10 is removed as shown in FIGS. 2 and 3 (b). Concrete C rushes into the front panel 1
4 is built. At this time, due to the lateral pressure of the concrete C cast in the slot 14a, the irregular projection A of the mud-mixed concrete C is generated on the lower side of the box joint 10 as shown in FIGS. 2 and 3 (b). Occurs and this part is later cut.

A part of the flowing concrete C tries to wrap around into the setback space from the lower side of the box joint 10, but this is blocked by the sealing material 18, and the lower end of the partition plate 16 is made of concrete. Edged from C.

Furthermore, a small amount of concrete C that wraps around the inside of the slot 14a and both side plates 102 of the box joint 10 into the setback space through a narrow gap is filled with single-grain crushed stone 2
The crushed stone 20 is hardened with a very loose connection so that it does not penetrate into the space between the partition plate 16 and the insertion guide 104, and even if there is, it hinders the subsequent extraction work of the partition plate 16. There is no such amount.

Then, in succession to this connecting portion, as shown in FIG.
As shown in (3), the trailing slot 22a is excavated, and the hydro phrase cutter 24 cuts along the cutting line L corresponding to about half of the setback space of the preceding panel 14 in the thickness direction.

At this time, crushed stones 20 filled in the upper side
While falling apart due to vibrations and impacts during cutting, it falls to the bottom of the slot 22a and is discharged to the surface along with excavation by the sludge removal device equipped in the hydro phrase cutter 24. Next, the sealing material 18 is also cut in the middle of the thickness direction, floats on the ground surface and is discharged.

After that, the projecting portion A is cut, the concrete mixed with the mud is cut off, and the joining surface of the lower half portion is shaped into a flat shape.

After completion of the excavation work of the trailing slot 22a,
The reaction material is pulled out, and then the partition plate 16 is pulled out. In this work, there is no sticking of the partition plate 16 due to hardening of the concrete C, or the amount given to the pull-out resistance is extremely small. The plate 16 can be easily pulled out by applying a slight edge cutting force in addition to the weight of the plate 16 and pulling up.

After excavation of the slot 22a, as shown in FIG. 3 (d), a rebar cage 26 having the same structure as described above is installed.
In this case, a box joint 28 similar to the above is attached in advance to the rebar cage 26 in the splicing direction, and the box joint 1
Within 0, the horizontal reinforcements of the reinforcing cages 12 and 26 are arranged so as to overlap each other, thereby ensuring the joint strength.

Thereafter, if the next box joint 28 is closed with a partition plate and filled with crushed stone in the same manner as described above, the preparatory work for placing concrete C is completed, and the trailing panel 22 is integrated with the preceding panel 14 by the placing. It will be handed down. Therefore,
After that, by repeating the work shown in FIGS. 3 (a) to 3 (d), the upper half part is rigidly connected and the lower half part is constructed of the concrete continuous walls by joining the concrete Cs by the cutting joint. .

In the above embodiment, the sealing material 18 is integrally formed only under the tip surface of the partition plate 16, and
The crushed stones 20 were filled in the upper setback space of the sealing material 18, but the crushed stones 20 were filled by integrally molding the sealing material 18 on the entire back surface of the partition plate 16 so as to contact the entire groove hole end portions of the preceding panel. Can be omitted (claim 2).

[0031]

As described above in detail with reference to the embodiments, in the joint structure for the underground continuous wall according to the present invention, the lower surface side of the partition plate is sealed by the sealing material at the time of placing concrete of the preceding panel. It is possible to prevent concrete from creeping into the ground. Immediately after the construction of the preceding panel, excavation of the groove of the succeeding panel and cutting of the lower part of the box joint are performed, and then the partition plate is pulled out, so that the pull-out resistance of the partition plate is greatly reduced.

Particularly, in the invention according to claim 1, the crushed stones filled in the setback space withstand the lateral pressure of the concrete, and the filled crushed stones are cut off at the time of cutting and naturally fall. The drawing resistance of is drastically reduced.

Therefore, by using the box joint having the above structure, there is no need to pull out the trailing panel when excavating the trailing panel when the conventional double partition plate is provided, and the number of setup changes can be reduced. Since the resistance is small, the work efficiency can be greatly improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part of a box joint according to the present invention.

FIG. 2 is a sectional perspective view showing a completed state of assembly of the box joint.

3 (a) to 3 (d) are explanatory sectional views showing a construction procedure using the box joint.

[Explanation of symbols]

 10,28 Box joint 12,26 Reinforcing bar basket 14 Preceding panel 14a Groove hole 16 Partition plate 18 Sealing material 20 Single crushed stone C Concrete L Cutting line

Claims (2)

[Claims] 1. A hollow box joint is arranged on the upper side of a joint portion with a trailing panel of a preceding panel forming an underground continuous wall, and the preceding panel and the following panel are arranged through the box joint. An underground continuous wall in which the upper side of the jointing part with and is rigidly connected integrally, and the lower side of the jointing part is a connection between concretes by a cutting joint, and the jointing surface is in the box joint. A partition plate that is installed at the setback position from the opening and closes the opening surface, a sealing material that is integrally molded under the tip end surface of the partition plate, and that is in contact with the groove hole end portion of the preceding panel, and the sealing material. Bottom wall, an upper end surface of the partition plate, and a crushed stone filled in a setback space formed between the end of the slot of the preceding panel and a crushed stone. Joint structure in. 2. A hollow box joint is arranged on an upper side of a joint portion with a trailing panel of a preceding panel constituting an underground wall, and the preceding panel and the following panel are arranged through the box joint. While rigidly connecting the upper part of the jointed part with and integrally,
A continuous underground wall in which the lower side of the splicing part is a connection of concrete by cutting, and the partition which is built into the set joint position from the splicing face opening in the box joint to close the opening face. A joint structure for a continuous underground wall, comprising a plate and a sealing material which is integrally formed on the entire rear surface of the partition plate and is in contact with the end of the slot of the preceding panel.