JPS59145824A - Construction of joint work of continuous underground wall - Google Patents

Abstract

PURPOSE:To simplify the construction of joints of a continuous underground wall by a method in which a locking box with a vertically grooved uneven surface is inserted into a trench, concrete is placed, the box is pulled out to form a space for a joint, and coupling iron bars are set into the space. CONSTITUTION:A trench 1a is excavated, a locking box 3 with sides having vertically grooved uneven surfaces and an iron bar cage 2a are inserted into the trench 1a, concrete is placed into the trench 1a and hardened, and the box 3 is pulled out to form a space 4a with large numbers of vertical grooves. In the same way, a trench 1b is excavated in the following wall section B, an iron bar cage (not illustrated) and the locking box 3 are inserted into the trench 1b, concrete is placed into the trench 1b, and the box 3 is pulled out to form a space (not illustrated) leading to the space 4a. An iron bar cage (not illustrated) for connection is inserted into the space and then concrete is placed to complete the construction of the joint work.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for constructing a joint in a continuous underground wall.

Cast-in-place reinforced concrete continuous underground walls, which are constructed by repeatedly inserting reinforcing bars into excavated trenches and pouring concrete, are used not only as earth retaining walls but also as the main walls of structures. This is largely due to advances in technology for firmly connecting joints between unit walls of continuous underground walls.

However, there are a wide variety of methods for connecting the splicing part with the joint, and none of them can be said to be perfect. For example, a partition plate is provided at the joint, and the horizontal main reinforcement is passed through it, and the side number of the next wall is made to protrude, and when pouring the conocret of the next wall, the reinforcement is placed in front of the reinforcing bar and at the lap joint. Although this method is effective, it is difficult to construct and has the disadvantage that the partition plates are left buried in the concrete, which is wasteful.

The present invention was made in view of these circumstances, and
By making the joint surface of the joint part uneven If we focused on preventing a decrease in the transmission of shear force acting on that surface, we purposely created a convex-convex shape along between the reinforcing bars of the lapped joint of reinforcing bars. By providing a joining surface, the above-mentioned drawbacks are eliminated.

Embodiments of the present invention will be described below with reference to the drawings.

The drawings are plan views showing the construction process of the joint part of a continuous underground wall in the order of steps, and the left side of each figure is the preceding wall part A;
The right-hand part shows the next wall part, the trailing wall part B.

First, as shown in Fig. 1, a groove 1a is excavated,
and insert locking box 3. The locking box 3 is a cylindrical body that is disposed between the main reinforcements at the ends of the reinforcing bars [2a] and has side surfaces parallel to the main reinforcements, and is designed so that the side surfaces have an uneven surface, for example. Detsuki play) 3b is stretched around the outer periphery of a steel frame M3a.

Then, concrete is placed in the groove 1a, and when the locking box 3 is pulled out after it begins to harden, the remains of the concrete is a notched space with many vertical grooves in a plane parallel to the continuous underground wall. 4a (Fig. 2).

Next, a groove 1b is excavated in the trailing wall portion B.

During excavation, the partition plate 5 prevents earth and sand from flowing into the notch space 4a, but this partition plate is removed after excavation. At that time, the end surface 6 of the preceding wall body is cut by a wall cutting device (not shown. Note that this device can also be used as an excavator with a drum cutter set).
If it is cut more shallowly, it will have a structural effect.

Further, the trailing wall reinforcement 2b and the locking box 3 are inserted into the groove 1b as shown in FIG. 3. The members and arrangement of these are almost the same as those of the preceding wall, but the difference is that the lateral pressure of the concrete is handled by the reaction force receiver 7 rather than by the partition.

In the drawing, the reaction force receiver 7 is a hydraulic cylinder attached to the locking box 3, but a frame with a certain width may be inserted separately.

In this way, concrete is placed in the full area 1b, and after the concrete starts to harden, the locking box 3 is similarly pulled out. Then, a trailing wall recess space 4b is formed which communicates with the recess space 4a of the preceding wall that has already been formed (Fig. 4).6 Then, after cleaning the wall surface, a recess space 4b is formed that communicates with the recess space 4a of the preceding wall. The reinforcing bars [2c] are inserted, concrete is poured, and the construction of the joint is completed.

As a result, the horizontal main reinforcement of the preceding wall forms a lap joint with the horizontal main reinforcement of the connecting reinforcing bar 2c through the joint surface parallel to the continuous underground wall, and the joint surface that exists between them. Since it is an uneven surface with vertical grooves, it does not impair the transmission of shear force of the concrete and increases the structural strength of the joint.

In this example, a locking box was also used on the trailing wall side, but this was not used and the trailing wall reinforcing bar 1
1R2b and the front connection reinforcing bar 2c are integrally formed and inserted, and the Nib of the trailing wall body and the notch space 4a of the leading wall body are inserted.
Even if concrete is poured at the same time, the effects of the present invention will not be impaired.

As described above, since the present invention provides an uneven joint surface between the horizontal main reinforcements of the leading wall and the trailing wall that form a lap joint, the main reinforcement is provided on the weir plate of the joint surface. There is no need to penetrate the weir, and therefore a locking box can be used in place of the weir plate, which has the advantage of maintaining the structural strength of the joint without leaving the weir plate unfilled.

[Brief explanation of the drawing]

1 to 4 are plan sectional views showing an embodiment of the present invention in the order of steps. lal lb- groove, 2 a % 2 b % 2 c
・-In front of reinforcing bar, 3... Locking box, 3a...
・Steel frame, 3b...Deck plate, 4a, 4b
... Notch space portion, 5 ... Partition plate, 6 ... Leading wall end face, 7 ... Reaction force receiving patent applicant Oaibe Kinu Co., Ltd.

Claims (1)

[Claims] (+) When constructing a continuous underground wall by repeatedly inserting the reinforcing bar into a 1 liter cut groove and pouring concrete, when inserting the reinforcing bar, at least the next wall side 2 at the end
A locking box whose surface along the main reinforcing bars has an uneven vertical groove is inserted between the rows of main reinforcing bars, and after concrete is poured, it is removed and cut into the joint to form a space, and this space is A method of constructing a joint part of a continuous underground wall, characterized by inserting reinforcing bars at the joint part common to the next wall part, and then pouring concrete. (2) The method for constructing a continuous underground wall joint according to claim 1, wherein the vertically grooved uneven surface is a deck plate.