JP3236582B2 - Concrete drilling method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for drilling a pile hole required for constructing a cast-in-place pile in concrete.

[0002]

2. Description of the Related Art A steel caisson is submerged in water, concrete is poured into a caisson frame, and a cast-in-place pile is formed by full rotation from above the caisson in order to firmly fix the concrete to the ground. That is, cast-in-place piles are constructed from concrete to ground. In order to construct cast-in-place piles in concrete, it is necessary to process pile holes in concrete in advance.

For example, there is a method in which, before casting concrete in a caisson frame, a box is punched out of a steel pipe having the same inner diameter as the pile hole, and then concrete is cast and the pile hole is processed into concrete. However, such a method requires labor and time to firmly fix the steel pipe.
Furthermore, when concrete is cast, the steel pipe and the fixing material required for fixing are buried and uneconomical.

[0004] For this reason, there is a method of omitting box removal with a steel pipe, casting concrete in a caisson frame, and subsequently processing a pile hole. In this method, a casing machine is used to cut around a cast-in-place pile by pushing a casing tube while rotating the casing tube. next,
The cast-in-place pile is excavated and the pile hole is machined by removing the concrete existing inside the casing tube using a hammer rub. However, when excavating a hard part such as a concrete foundation, the periphery of the drilled portion is cut by the tip of the casing tube, but it is difficult to remove the core part in the casing tube with a hammer rub.

[0005] Therefore, as shown in FIG. 6, after the concrete 140 is cut by the casing tube 150, the chisel 170, which is a heavy weight, is dropped inside the casing tube 150 and collides with the concrete 140, thereby causing the casing 140 to collide with the concrete 140. After crushing the drilled portion 141 in the tube 150, the concrete fragments 144 generated by the crushing are repeatedly discharged by a hammer club (not shown), thereby drilling.

[0006]

However, in such a method, when the concrete 140 is cut by the casing tube 150, the casing tube 15 is cut.
0 and the concrete of the non-drilled portion 142 and the drilled portion 141 are in close contact with each other, and there is almost no gap.
Only concrete in the vicinity of the collision portion with zero can be crushed, and the crushing efficiency of concrete is poor.

Furthermore, when concrete is present in water, the impact force of the drilled portion 141 of the chisel 170 on the concrete is attenuated by the collision of the chisel 170 with the water surface and the buoyancy in the water. Spends a lot of time and is inefficient.

Further, when the chisel 170 collides with the concrete in the drilled portion 141, the chisel 170 may adversely affect the concrete in the surrounding non-drilled portion 142, and the quality of the concrete is not reliable.

Accordingly, an object of the present invention is to provide a concrete drilling method capable of efficiently crushing concrete and not adversely affecting surrounding concrete caused by weight collision.

[0010]

In order to solve the above-mentioned problems, the invention according to claim 1 provides a tubular member (for example, a fume pipe 20) whose impact strength is substantially equal to or less than that of concrete.
Erecting the concrete at the place where the concrete is to be cast, casting the concrete (40) around the tubular member, and after setting the concrete, setting the weight on the tubular member and the surrounding concrete from above. (Eg Chisel 70)
And a step of crushing and drilling the cylindrical member and the concrete around it by repeatedly dropping the concrete.

As described above, according to the first aspect of the present invention, concrete can be box-punched out of a cylindrical member having an impact strength substantially equal to or less than that of concrete, and the weight is dropped to remove the cylindrical member and the surrounding concrete. Can be easily crushed.
Moreover, since the concrete is crushed in the direction of the boxless portion, it is possible to reduce the adverse effect on the concrete of the surrounding non-drilled portion due to the weight collision.

According to a second aspect of the present invention, there is provided the concrete drilling method according to the first aspect, wherein the casing tube (50) is rotated and pushed into the concrete around the cylindrical member, and the weight is dropped into the casing tube. Is characterized.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a concrete drilling method according to the present invention will be described below with reference to FIGS. FIG. 1 is a longitudinal sectional view showing an upright state of a cylindrical member used for drilling concrete as an example to which the present invention is applied, and showing an inside of a caisson submerged in water before casting concrete. . FIG. 2 is a longitudinal sectional view showing an operation of crushing and drilling the concrete with a weight after hardening the concrete poured into the caisson of FIG.

In this embodiment, as a first step, a caisson 10 made of steel is laid down. Then, as a second step, prior to placing concrete in the caisson 10, as shown in FIG.
Is erected. In the subsequent third step, as shown in FIG. 2, concrete 40 is poured into the caisson 10, and after the concrete 40 is hardened, the fume pipe 20 and the surrounding concrete portion are removed as described later. Crush and drill. Further, as a final fourth step, a cast-in-place pile is formed in the drilled portion by a full turn from above the caisson 10. In addition, the technique of laying a caisson and the technique of forming a cast-in-place pile by full turning are well-known techniques, and thus description thereof is omitted here.

Next, as shown in FIG.
A process of erecting the fume pipe 20 before placing the concrete 40 in the interior will be described. In this step, the fume pipes 20a, 20b,... In this case, as shown in FIG. 3, the fume pipes 20 a and 20 b are connected on land using the temporary joining lumber 33 and the temporary joining number wire 34.

Next, the fume tubes 20a, 20b connected by using a crane are suspended and erected in the caisson 10 while being suspended. The fume tubes 20a and 20b are fixed to the caisson 10 using the fixing reinforcing bar 31 in order to prevent the fume tubes 20a and 20b from falling over. Further, since the fume pipes 20a and 20b generate buoyancy when the concrete is poured, the fume pipes 20a and 20b are prevented from being lifted up by the lift prevention rebar 32 connecting the fume pipe 20b and the caisson 10. In this manner, the fume pipes 20a, 20b,... Are increased upward, and as shown in FIG. 2, the height H of the fume pipe 20 as a whole is the thickness h of the concrete layer to be cast. Stand upright.

As described above, after the fume pipes 20, 20, 20, 20 are erected along the circumferential direction in which the hole is to be drilled in the next step, as shown in FIG. Set up. After the cast concrete has hardened, the casing tube 50 is installed from the work place 100 above the caisson 10 toward the fume pipe 20 so that the fume pipe 20 is disposed in the casing tube 50. From 100, it is suspended using a casing machine 60.

Next, a heavy chisel 70, for example, a weight of about 7.5 t is suspended in the casing tube 50 by a crane 90 via a rope 80. Here, the chisel 70 has a cross shape as shown in FIG.
The lower end of the chisel 70 is a cross-shaped blade 71 for easily crushing the fume tube 20 and the concrete 40 around it. The upper part of the chisel 70 is provided with a hollow portion 72 corresponding to a cross shape so as not to receive resistance in water.
A circular frame portion 73 having 72, 72, 72 is provided.
The diameter D of the chisel 70 is larger than the inner diameter d of the fume tube 20.
00 mm, the diameter of the chisel 70 is 1750 mm or the like.

As described above, when the crane 90 is used to freely drop the chisel 70 toward the fume tube 20 and the concrete 40, holes are drilled. First, while rotating the casing tube 50 by the casing machine 60, the concrete portion around the fume tube 20 is cut, and the casing tube 50 is pushed into the concrete portion around the fume tube 20. Next, the chisel 70 is allowed to fall freely into the casing tube 50, and FIG.
As shown in the enlarged view, the fume tube 20 in the casing tube 50 and the concrete portion around the fume tube 20 collide with the cross-shaped blade 71 of the chisel 70, thereby crushing the fume tube 20 and the surrounding concrete portion. Concrete fragments 43 resulting from the crushing fall into the internal space 41 of the fume tube 20. After performing this crushing to a predetermined depth, concrete fragments 43 that have fallen into the internal space 41 of the fume tube 20 are taken out by a hammer club (not shown). The drilling is completed by repeating the above.

According to the above-described embodiment, as shown in FIG. 5, since the concrete 40 has a box-cut portion by the fume tube 20, when the chisel 70 collides with the fume tube 20 and the concrete around it, Tube 2
Since the 0 pieces and the concrete pieces 43 around the 0 pieces are crushed into the box-extracted portion (the internal space 41 of the fume tube 20), the concrete at the lower portion can be crushed, and the concrete can be easily crushed.

Further, the fragments of the fume tube 20 and the concrete fragments 43 fall into the internal space 41 of the fume tube 20, that is, the concrete is crushed in the direction of the boxless portion, so that it collides with the surrounding non-perforated portion. Adverse effects are reduced.

In the above embodiment, the concrete 40 is underwater. However, for example, the chisel 70 cannot be hung high and the chisel 70 is lightweight. It is also effective when it is difficult to drill holes.

Although the cylindrical member is a fume tube made of concrete, it may be a cylindrical member made of vinyl chloride, paper, styrene foam, or the like. However, in water, the workability deteriorates because of the large buoyancy of vinyl chloride and foamed styrene, and the wettability of paper.
Therefore, when drilling underwater concrete, it is effective to use a fume pipe. In addition, it goes without saying that specific details such as the step of erecting the tubular member, the step of placing concrete, and the shape of the weight can be appropriately changed.

[0024]

As described above, according to the method for drilling concrete according to the present invention, since concrete is boxed out of a cylindrical member having an impact strength substantially equal to or less than that of concrete, the weight is dropped and the cylindrical member and its The surrounding concrete can be easily crushed, and the crushing efficiency can be improved.

Further, since the concrete is crushed in the direction of the boxed portion, the adverse effect on the non-perforated portion around due to the weight collision can be reduced, and therefore, the reliability of the concrete around the perforated portion can be improved. Can be achieved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an upright state of a cylindrical member used for concrete drilling as an example to which the present invention is applied, showing an inside of a caisson submerged in water before concrete is poured. is there.

FIG. 2 is a longitudinal sectional view showing an operation of crushing and drilling the concrete with a weight after hardening the concrete poured into the caisson of FIG.

FIG. 3 is an enlarged view showing a specific example in which a cylindrical member is erected in the caisson of FIG.

FIG. 4 is an enlarged perspective view showing a chisel used for drilling concrete in FIG. 2;

FIG. 5 is an enlarged view showing a concrete crushed state in the concrete drilling hole of FIG. 2;

FIG. 6 is a longitudinal sectional view showing a conventional concrete crushing example.

[Explanation of symbols]

 Reference Signs List 20 fume pipe (cylinder member) 40 concrete 41 cylinder member inner space 43 concrete debris 50 casing tube 70 chisel (weight) 71 cruciform blade

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) E21B 1/00 E02D 23/08

Claims (2)

(57) [Claims] A step of erecting a cylindrical member having an impact strength substantially equal to or less than that of concrete at a place where the concrete is to be cast; a step of casting concrete around the cylindrical member; After hardening, repeatedly dropping the weight onto the cylindrical member and surrounding concrete from above, thereby crushing and drilling the cylindrical member and surrounding concrete, and concrete. Drilling method. 2. The method for drilling concrete according to claim 1, wherein the casing tube is rotated and pushed into the concrete around the cylindrical member, and the weight is dropped into the casing tube.