JPH07109097B2 - How to pull out a pile - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for extracting cast-in-place piles.

(Prior art) Reinforced concrete cast-in-place piles that were constructed using earth drills, reverse circulation machines, Benoto excavators, etc. were removed from existing piles when rebuilding due to deterioration of the building. Construction of new piles is required. However, if it is a pine pile or a simple ready-made pile, it can be excavated by pulling out around the pile, but in the case of cast-in-place pile, since the pile is long and has a large diameter, it cannot be easily pulled out, Is
Using the so-called deep foundation method, etc., the surroundings of the piles are excavated manually, and the piles are lifted by cranes or the like while preventing the soil from collapsing with a framework. In addition, a method of cutting concrete and rebar of the pile over the entire cross section by installing a blade with a cutter on the inside of the tip of the casing bit of the casing driver with a diameter larger than above the pile and rotating it I am taking it. Because of this, labor and labor costs,
It takes a long period of time, and since excavation and frame work, frame dismantling, and mounting of pile lifting members are performed by manual work, it is not preferable in terms of work safety.Because the pile is long and has a large diameter, There was a problem that a large crane or the like was required to pull it out.

(Problems to be Solved by the Invention) In view of the above problems, the present invention is a water jet device capable of safely, easily, efficiently and inexpensively performing work, and capable of cutting a pile into an arbitrary length. The purpose of the present invention is to provide a method for pulling out piles.

(Means for Solving Problems) In order to achieve this object, a method for extracting a cast-in-place pile of the present invention is to drill a hole in the center of a concrete portion of the pile by an excavator,
A feature that the pile is pulled out by excavating the earth and sand on the outer periphery of the pile with a steel pipe having a diameter larger than that of the pile, and repeating at least the following operations (a) and (b) with the steel pipe embedded in the ground. And

(A) A water jet device is inserted into a vertical hole drilled by the excavator so that the bottom position of the vertical hole drilled by the excavator is always below the pile cutting position by the water jet device. The work of cutting the pile by adjusting the pressure so as not to cut the pipe and injecting high-pressure water from the water jet device.

(B) After performing the work of (a), a lifting device for pulling up the cut pile block is inserted into the vertical hole, and the pile block is pulled up.

When cutting the pile with the water jet device, the vertical hole bottom position drilled by the excavator may be always located below the pile cutting position with the water jet device. The work of drilling a hole with an excavator may be first performed to the bottom of the pile, or may be performed in advance every time the pile is cut with the water jet device.

(Operation) In the method for extracting a cast-in-place pile according to the present invention, the friction between the pile and the surrounding soil is cut by excavating the earth and sand around the pile with a steel pipe having a diameter larger than that of the pile. In addition, a vertical hole is drilled in the concrete part, a water jet device is inserted thereinto, the pile is cut into blocks, and each block is pulled up. Depending on the lifting capacity of the crane, etc., the cutting position of the pile is to be cut at any position so that the weight of the cut pile does not exceed that capacity. Since the pressure is adjusted so as not to cut the steel pipe during cutting with the water jet device, the steel pipe is not cut. Further, since the bottom position of the vertical hole drilled by the excavator is always positioned below the pile cutting position by the jet device, a part of the cutting waste generated by the cutting escapes to the vertical hole, and the water jet device. It is possible to avoid the state where the cutting debris is blocked in front of.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an embodiment of a method for extracting cast-in-place piles according to the present invention. (A) is a cast-in-place pile 1 which is buried in the ground, and has reinforcing steel bars 2 for taking a tensile load. For such a pile 1, first, as shown in (b), the center of the pile 1 is drilled by a medium excavator such as an auger 3 having a carbide bit at the lower end. As a medium digging excavator,
For example, a device in which a drive device for the auger 3 is attached so as to be able to move up and down along a reader attached to the work machine body is used.

A vertical hole 6 as shown in (c) by such an auger 3 or the like.
After piercing the pile 1 to the bottom of the pile 1, pull up the auger 3 (c).
As shown in, the casing driver pushes the steel pipe 4 around the pile 1 while rotating or rocking the pile 1 to excavate the earth and sand and cut the friction between the pile 1 and the surrounding soil. As the casing driver, for example, Japanese Patent Application No. 60-11
The one described in No. 2,073 is used. In addition, the friction is cut by softening the outer periphery of the pile 1 while ejecting water from the lower end of the steel pipe 4, suspending the steel pipe 4 with a crane or a pile driver, and applying the downward force or its own weight. You may make it crowded.

In this way, after the steel pipe 4 has been built up to the lower part of the pile 1 by bolt connection as shown in (d), the water jet device 5 is put in the vertical hole 6 and the pile 1 is cut off at the site. By inserting the jet port 5a of the water jet device 5 to a place where it can be lifted by a crane or the like and ejecting a high-pressure water jet from the jet port 5a, the reinforcing bar 2 and the pile 1
Disconnect. In this case, the distance between the cutting surface of the cutting member and the ejection port 5a and the ejection pressure are set appropriately considering the hardness and strength difference between the concrete and the reinforcing bar 2 and the steel pipe 4 which constitute the pile 1. , Concrete and rebar 2
Only the steel pipe 4 can be cut, and the steel pipe 4 can be prevented from being cut.

In addition, if the cutting waste generated when the pile is cut by the water jet device 5 stays at that position, the high-pressure water jetted from the jet port 5a does not directly hit the cut surface, resulting in a significant loss of jetting energy. In the example, a vertical hole is drilled in the center of the concrete in advance, and at least the vertical hole bottom is located below the cutting position by the water jet device, so a part of the cutting waste escapes into the vertical hole, and the front of the ejection port 5a is tightly packed. It is possible to avoid the state where the cutting chips are clogged, and it is possible to reduce the energy loss.

Moreover, the cutting position of the pile can be set to an arbitrary position depending on the lifting capacity of the crane or the like, within a range in which the weight of the cut pile does not exceed the capacity.

Next, as shown in (e), the cut pile block 1A is hoisted using the hoisting device 20. This lifting device 20 has a second
As shown in the figure, left and right parallel links 10 and 10 each mounted on the left and right of the main shaft 9 so as to be vertically rotatable about upper and lower pins 11 and 11, and two parallel links 10 and 10, respectively. The upper and lower ends are rotatably connected to the tip of the pin by a pin 12, and two sets of parallel link mechanisms, each of which is composed of a guide 13 provided with a biting protrusion 14 on the outer surface, are provided. It is connected to the main wire rope 7 to be unwound and the upper part of the parallel links 10 on the left and right is connected to the auxiliary wire rope 8 to be unwound and unwound by the auxiliary winding winch.

When lifting the pile block 1A, use the auxiliary wire rope 8
The main wire rope 7 is loosened, and the main wire rope 7 is loosened to reduce the space between the left and right guides 13 and 13 and the hoisting device 20 is put in the vertical hole 6, and subsequently the main wire rope 7 is stretched in the opposite direction to the above. Loosen the supplementary wire rope 8 and the guide 13
To the outside so that the protrusion 14 bites into the inner wall of the vertical hole 6,
By pulling up the main wire rope 7 in this state, the cut pile block 1A can be lifted as shown in FIG. 1 (e). In this case, the larger the weight of the pile block 1A is, the stronger the guide 13 is in close contact with the wall surface of the drilled hole, and the stronger the grip of the pile block 1A is. In addition, pile block 1A
The hoisting device 20 is not limited to the one having the above-described configuration, and for example, a parallel link is formed by a hydraulic cylinder.
A structure that moves 10 can be used. Also,
Alternatively, the outer peripheral surface of the pile block 1A may be gripped and lifted.

However, as shown in FIG. 2, by constructing the lifting device 20 from the two wire ropes 7 and 8, the link mechanism, and the guide 13, a hydraulic cylinder or the like for gripping the pile becomes unnecessary. As a result, the structure of the gripping device becomes simple, the cost can be provided at low cost, and the pile block can be securely gripped and released.

After sequentially removing the pile blocks 1A in this way, the steel pipe 4
To complete the drawing operation.

(Effects of the Invention) As described above, the method for extracting cast-in-place piles according to the present invention is to drill a vertical hole in the center of the concrete portion of the pile, and use the vertical hole to cut the pile or pull the block of the cut pile. It is necessary to excavate the entire cross section using an earth auger, etc. by inserting a device for raising it and by press-fitting a steel pipe with a diameter larger than the pile in order to cut the friction on the outer peripheral surface of the pile. There is no need to excavate the outer circumference of the pile, construction of the frame, dismantling and installation of the pile lifting member by human power, so the pile extraction work is efficient, less labor, and inexpensive in a short construction period. In addition, it is possible for the worker to perform the work safely because it is not necessary for the worker to enter the groove provided on the outer periphery of the pile.

In addition, since the pile is cut into blocks of any size and lifted up, it is easy to dispose of the pile, and work can be performed using a small crane or the like even in a narrow space. You can

Further, since the pile is cut by the water jet, the work can be performed safely and reliably.

In addition, a vertical hole was drilled in the center of the concrete part, and at least the bottom of the vertical hole was positioned below the cutting position by the water jet device, so that some of the cutting chips escaped to the vertical hole, and a sharp cut was made in front of the injection port. It is possible to avoid a state in which debris is clogged, and it is possible to reduce energy loss of high-pressure water due to the water jet device.

Also, with the steel pipe still buried in the ground, only the pile is cut by injecting high-pressure water from the water jet device while adjusting the pressure so as not to cut the steel pipe, so the steel pipe is pulled out each time the pile is cut. Compared with the case, it is possible to efficiently carry out the drawing work.

In addition, since the outer circumference of the pile is made to be excavated by the steel pipe,
There is no leftover soil as in the case of excavating a groove enough for a person to enter the outer periphery of a pile, as in the past.

[Brief description of drawings]

1 (a) to 1 (e) are process drawings showing an embodiment of a method for extracting cast-in-place piles according to the present invention, and FIG. 2 is a side view showing a hoisting device used in the embodiment.

Claims (1)

[Claims] 1. A center of a concrete portion of a pile is drilled by an excavator, earth and sand on the outer periphery of the pile are excavated by a steel pipe having a diameter larger than that of the pile, and at least the following (a) while the steel pipe is buried in the ground: , (B) is repeated to pull out the pile. (A) A water jet device is inserted into a vertical hole drilled by the excavator so that the bottom position of the vertical hole drilled by the excavator is always below the pile cutting position by the water jet device. The work of cutting the pile by adjusting the pressure so as not to cut the pipe and injecting high-pressure water from the water jet device. (B) After performing the work of (a), a lifting device for pulling up the cut pile block is inserted into the vertical hole, and the pile block is pulled up.