JPS63223215A - In-situ concrete piling work - Google Patents

Abstract

PURPOSE:To reduce the cost of construction by placing ready-mixed concrete from the tip of an excavator into a pile pit with residual excavated soil. CONSTITUTION:A pile pit 11 with residual excavated soil 10 is excavated by using an excavator 1 having a screw 3 on its tip. Ready-mixed concrete 12 is placed from the tip of the excavator 1 while moving it upwards, and a steel tube 13 is inserted into the concrete 12 to form a pile body 15. The construction cost can thus be further reduced than the conventional methods because of no-use of bentonite mud water.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a cast-in-place concrete construction method for constructing concrete foundation piles etc. underground.

[Conventional technology]

Generally, when constructing a concrete pile, a hole that is difficult to penetrate underground is excavated using an excavator called a screw auger or an earth auger, and the collapse of the hole wall is prevented until the concrete is poured into the hole. It is filled with bentonite water for the purpose of prevention and covering.

(Problems to be Solved by the Invention) In the conventional method described above, it is necessary to drain bentonite mud from the borehole during concrete pouring, and after draining the bentonite mud, the bentonite that has adhered to the hole wall must be washed. There were restrictions such as the inability to place concrete unless the material was removed.

In addition, the discharged bentonite mud cannot be disposed of as it is, so bentonite, earth and sand in the mud are separated by some means, and other mixtures in the mud are removed before being disposed of as wastewater. Therefore, when implementing the construction method, many incidental facilities are required, leading to problems such as high costs.

This invention was devised to solve the problems of the conventional construction method described above, and its purpose is to create a new method that allows concrete foundation piles to be cast in place without using drilling stabilizing liquid such as bentonite slurry. Our goal is to provide construction methods.

[Means for solving problems]

This invention for the above-mentioned purpose uses an excavating body having a screw only around the tip of the tube, and by rotating the excavating body, excavates a pile hole in which excavated soil remains underground, and after the excavation is completed, piles are piled from the tip of the excavated body. Fresh concrete is poured into the bottom of the hole, and the excavated body is moved upward along with the remaining excavated soil, filling the pile hole from the bottom to the top with fresh concrete, and then a steel pipe is inserted into the fresh concrete to complete the required pile body. By doing so, the above-mentioned conventional problems are solved.

〔Example〕

FIG. 1 shows one example of an excavator used in the present invention, and 1 is an excavator having a screw 3 only around the tip of a tube 2, and the tube 2 has a bit 4 (not shown in the drawing). There is a concrete injection pipe that opens at the tip where the concrete is attached, and a mortar pressure feed pipe that has an injection port on the side of the tip.

The excavating body 1 has a pipe body 2 inserted through a rotating device 6 provided at the lower part of the excavating tank 5, and a sheave 8 of the IC 1 part of the excavating tank 5 together with a weight 7 that moves along the side of the excavating tank 5. It is rotatably suspended and set on an excavator.

Figure 2 is an explanatory diagram of the process from drilling a hole to placing concrete foundation piles. After the bit 4 of the excavation body 1 is grounded, the rotary bag @ 6 is loaded with a weight 7.
is activated, the screw 3 and bit 4 are rotated together with the pipe body 2, and excavation of the ground 9 is started.

This excavation is carried out while adding the pipe body 2 to a predetermined depth while leaving the excavated soil 10 between the screws 3 and around the pipe body 2 with soil remaining therein. Therefore, the excavated borehole 11 remains filled with excavated soil 101fi.

When the excavation of the pile hole 11 is completed, the rotating device 6 is stopped, and the excavated body 1 is made free with respect to the rotating device 6, and then the ready-mixed concrete 12 is pumped into the tube from the upper part of the tube 2. , fresh concrete 12 is placed at the bottom of the hole from the tip of the tube.
inject.

The excavated body 1 and excavated soil 10 are pushed upward by this injection pressure, and the excavated area ±10 of the borehole 11 is gradually replaced with fresh concrete 12 as the amount of injection increases. In some cases, the ready-mixed concrete 12 may be poured while the excavated body 1 is being pulled up.

When the pouring of the fresh concrete 12 is completed, a predetermined steel pipe 1 prepared in advance is inserted into the fresh concrete 12.
Insert 3. Spacers 14.14 are protruded from the outer surface of the steel pipe 13 at regular intervals, and the spacers 14.14 allow the steel pipe 13 to be built perpendicularly and concentrically to the borehole 11. A concrete foundation pile 15 with a built-in steel pipe 13 is completed.

In addition, if a bottom-expanding pile is required, before pouring the fresh concrete 12, while rotating the excavation body 1, high-pressure mortar is injected from the tip of the pipe body onto the circumferential wall at the bottom of the hole to partially cover the bottom hole wall. After excavating, ready-mixed concrete 12 is poured.

〔Effect of the invention〕

As described above, this invention excavates a hole in the ground in which excavated soil remains by rotating an excavating body having a screw only around the tip of the pipe body, and after excavation is completed, the excavated soil is passed from the bottom of the hole through the excavating body. By pouring fresh concrete to the top and then inserting steel pipes into the fresh concrete to complete the required cast-in-place concrete piles, there is no need to use bentonite slurry, which is problematic as industrial waste.
In addition, there is no need to clean the hole walls when pouring fresh concrete, and compared to conventional construction methods, not only the process but also the excavation equipment is simplified, resulting in a significant reduction in construction costs.

Furthermore, it has great applicability, such as being able to easily excavate hard ground by changing the bit, and making it possible to create bottom-expanding piles.

[Brief explanation of the drawing]

The drawing shows one of the cast-in-place concrete pile construction methods according to this invention.
An example is shown, and FIG. 1 is a schematic front view of an excavator, and FIG. 2 is a process explanatory diagram. 1... Excavation body 2... Pipe body 3... Screw 4... Bit 5... Excavation tank
6... Rotating device 7... Weight 9.
...Ground 10...Drilling± 11...Pits 12...Ready-mixed concrete 13...Steel pipe 14...
... Spacer 15 ... Basic stake patent applicant Tenox Co., Ltd. Tokki Kogyo Co., Ltd. Figure 1

Claims (1)

[Claims] Using a drilling body with a screw only around the tip of the tube,
A pile hole with residual excavated soil is excavated into the ground by the rotation of the excavation body, and after the excavation is completed, fresh concrete is poured into the bottom of the pile hole from the tip of the excavation body, and the excavation body is moved upward with the remaining excavated soil. A cast-in-place concrete pile construction method characterized by filling ready-mixed concrete from the bottom to the top of the pile hole, and then inserting steel pipes into the ready-mixed concrete to complete the required pile body.