JPH0672417B2 - How to remove a continuous concrete wall - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for removing a concrete continuous wall, and more particularly, to easily cut off a planned cutting position of a reinforcing bar embedded inside the continuous wall by using a shape memory alloy. Concerning the method that was made possible.

《Conventional technology》 When it is necessary to remove a temporary structure using continuous walls made of reinforced concrete to a certain depth after construction, conventionally, concrete at the planned separation position is removed by chipping, etc., and the exposed reinforcement is cut. It was supposed that the removal work would be completed by fusing and cutting.

<< Problems to be Solved by the Invention >> However, this removal work requires a great deal of labor and time, and has drawbacks such as noise.

Further, such a method can be applied only to a relatively shallow portion because removal work in the ground or underwater at a large depth is dangerous.

The method of the present invention solves the above problems, and an object of the present invention is to provide a method for removing a continuous concrete wall that can easily and quickly remove unnecessary portions of the continuous concrete wall using a shape memory alloy even at a large depth. And

<Problems to be Solved by the Invention> In order to achieve the above object, the present invention is a method of cutting and removing a continuous wall made of reinforced concrete at a predetermined position after construction, in which a heater is wound around the reinforcing bars at the predetermined position. While pre-joined with a sleeve made of a turned shape memory alloy, drilling an injection hole along the predetermined position, injecting a static crushing agent into this hole, crushing the concrete part,
By energizing the heater to deform the shape of the sleeve,
The restraint between the reinforcing bars is released.

<< Action >> The static crushing agent injected into the concrete part expands to increase the volume, pressurizes the peripheral concrete, and crushes and separates the concrete along the planned cutting position (predetermined position). Further, the sleeve made of the shape memory alloy is deformed to the memorized state by the heating of the heater, and the restraint state of the outer periphery of the joint portion between the reinforcing bars is released.

<< Embodiment >> An embodiment of the present invention will be described in detail below with reference to the drawings.

1 to 7 show an embodiment in which the method of the present invention is applied to a temporary earth retaining wall.

In Fig. 1 and Fig. 2, the concrete continuous wall 1 which constitutes the temporary earth retaining wall is cut so that the lower side 1a is buried as a part of the underground structure and the upper side 1b is removed after the underground structure is constructed. It is designed to cut along the planned position S.

And this concrete continuous wall 1 constructs a reinforced basket 3 inside the excavation groove 2 excavated in the ground E while enclosing the construction planning area E1 of the underground structure, and then the concrete 4 inside the excavation groove 2 The construction is completed by placing.

The reinforcing bar cage 3 is a rectangular cage formed by binding the horizontal bars 6 to the vertical bars 5, and as shown in FIG. 1, the vertical bars 5 at the planned cutting position S are separated beforehand. As a result, the reinforcing bar cage 3 is divided into a lower reinforcing bar cage 3a, which is a structure that is buried in the ground, and an upper reinforcing bar cage 3b, which is removed after the completion of temporary construction work. By fitting a joining sleeve 7 made of a shape memory alloy on the outer periphery, the respective reinforcing bar cages 3a, 3b are integrally joined.

At a normal temperature, this sleeve 7 is kept in a tubular shape, and the outer circumferences of the joint ends of both longitudinal bars 5 are joined in a tight fit state.

Further, it is memorized that the sleeve 7 becomes a flat plate shape when the temperature becomes high. Therefore, the sleeve 7 presses the concrete on the outer periphery to open, and the restraint between the both vertical bars 5 is released. 5 can be easily pulled out from the lower vertical streak 5.

A heater 8 made of nichrome wire or the like for heating is wound around the outer circumference of the sleeve 7, and lead wires of these heaters 8 are wound.
8a is wired to a power receiving box 9 arranged on the side of the lower reinforcing bar 3a, and is connected to an external power source through a lead wire 10 led from the power receiving box 9 to the surface side.

The continuous wall 1 constructed as described above is used as an ordinary earth retaining wall after construction, and when the construction is completed, as shown in FIG. Build the structure 12.

After the construction of the underground structure 12 is completed, the upper side 1b of the continuous wall 1 becomes unnecessary and is removed.

At the time of removal, as shown in FIG. 4, a plurality of injection holes 14 are drilled at predetermined intervals in the direction orthogonal to the paper surface along the planned cutting position S, and the injection holes 14 are drilled inside. Inject static crushing agent 15.

This static crushing agent 15 is, for example, calcium oxide such as quicklime mixed with water and reacted. After the reaction, calcium hydroxide becomes calcium hydroxide to double its volume, and its pressure (about 300 k
The concrete is crushed by g / cm ² ) and the concrete portion 4 on the upper side 1b and the lower side 1a of the continuous wall 1 is separated along the planned cutting position S.

However, in this state, since the vertical streaks 5 are kept in the connected state, the upper side 1b does not fall inward and maintains independence.

Therefore, after the work of separating the concrete part 4 by the static crushing agent 15 is completed, the construction planned area E1 is backfilled with the earth and sand 16 as shown in FIG. 5 to prevent the upper side 1b from collapsing.

Next, the heater 8 is heated by energizing an external power source to the lead wire 10 led to the surface of the earth. The sleeve 7 is heated as the temperature of the heater 8 rises, and when the temperature reaches a predetermined temperature, the sleeve 7 is deformed to release the restraint of the vertical streak 5 from the outer periphery of the joint.

In this state, if the upper side 1b of the continuous wall 1 is lifted by a large crane or the like, as shown in FIG. 6, only the upper side 1b can be pulled out, and the removal work is completed.

Then, the extracted portion is backfilled with earth and sand 16 to complete the construction.

In addition, although the case where the present invention is applied to the earth retaining wall for temporary construction is shown in the above-mentioned embodiment, it is another temporary structure and needs to be removed after completion of the structure, for example, removal of temporary wall of concrete caisson. Of course, it can be applied to the end processing of the expansion planning section.

<< Effects of the Invention >> As described in detail with reference to the embodiments above, in the method for removing a concrete continuous wall according to the present invention, the concrete portion is cut along the planned cutting position with the static crushing agent filled inside the concrete. Since it is separated into crushed state and the sleeve made of shape memory alloy is deformed to separate the upper side reinforcing bar from the lower side reinforcing bar, compared to the conventional removal method by chipping, it can be used in deep water or underground. The removal work can be performed safely, reliably and economically.

[Brief description of drawings]

1 to 7 are explanatory views showing an embodiment when the method of the present invention is applied to a temporary earth retaining wall. 1 ... Continuous concrete wall 1a ... Lower side, 1b ... Upper side S ... Cutting plan position 3 ... Reinforcing bar cage 3a ... Lower side reinforcing bar cage, 3b ... Upper side reinforcing bar cage 4 ... Concrete 5 ... Vertical bar 6 ... Horizontal bar 7 ... Shape memory Joining sleeve made of alloy 8 ... Heater 8a, 10 ... Lead wire 14 ... Injection hole 15 ... Static crushing agent

Claims (1)

[Claims] 1. A method of cutting and removing a continuous wall made of reinforced concrete at a predetermined position after being constructed, wherein the reinforcing bars at the predetermined positions are pre-joined with a sleeve made of a shape memory alloy around which a heater is wound, The injection hole is drilled along the predetermined position, the static crushing agent is injected into the drilled hole, the concrete part is crushed, the heater is energized to deform the sleeve, and the reinforcing bars are joined together. A method for removing a continuous concrete wall, which is characterized by releasing the restraint of.