JPS5817849B2 - Foundation pile construction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for constructing foundation piles consisting of a composite of hollow pipes such as steel pipes or other concrete pipes and soil concrete.

Normally, steel pipe piles are constructed using one pile driver and one drive, which causes problems with noise and vibration, and there is a risk of corrosion inside and outside the pipe.

Method 1 to solve the above-mentioned problems The applicant developed a method disclosed in Japanese Patent Application Laid-Open No. 50-2304, which has not yet been put into practical use.

By the way, in the above construction method, as in the conventional example, one steel pipe pile is sunk into the drilled hole, and then the steel pipe pile is struck for stopping.

Therefore, it is necessary to prepare a pile driver, and it is difficult to perform completely noise-free and vibration-free construction.

This invention is an improvement to solve the above problems.
Example 1 will be explained below.

An auger 1 used in carrying out this construction method is provided with an auger head 3 having a hollow rod 2 at its end.

The auger head 3 has a tip 1 bit 4 followed by a helical blade 5. A stirring blade 6 is provided.

The hollow rod 2 is then rotated by a rotary drive device T.

In this case, first, as shown in Fig. 1, while injecting a hardened material 1 with low compressive strength after hardening from the tip of the auger head 3, for example, a slow-hardening ground hardening agent such as poorly mixed cement milk. The ground is excavated to a specified depth to reach the supporting layer.

A hardening material having a high compressive strength after hardening upon reaching the support layer, for example, a hardening hardening material such as rich blended cement milk, is injected in advance.

Subsequently, as shown in FIG. 2, the single auger head 3 is pulled up while rotating to mix the soil and hardening agent.

Next, as shown in FIG. 3, a single steel pipe 8 is suspended and rotated and press-fitted into the uncured fill concrete.

Next, as shown in FIG.
’ into the steel pipe 8 and rotate it until the steel pipe 8 reaches the specified depth.
Then, the auger head 3' is lowered, and the auger head 3' is inserted in advance of the steel pipe 8, and the hardening material 9, such as rich blended cement milk or concrete, is poured to the required depth 1, for example, 1.5D to 3D (D Pile diameter) As a specific example, the lower end of the steel pipe 8 is cemented by pouring to a depth of about 0.5 to 1.5 m.

Next, as shown in FIG. 5, the auger head 3' is pulled out while rotating, leaving one steel pipe β, and as shown in FIG.
The foundation pile is completed, with the inside and outside of this steel pipe 8 filled with soil concrete.

In addition, if the upper part of the steel pipe 8 is stuck, the soil concrete can be removed and concrete filled to increase the strength of the upper part of the foundation pile.

By the way, a spiral protrusion 10 is formed on the outer periphery of the steel pipe 8, particularly at least on the lower outer periphery thereof, so that when the steel pipe 8 is to be lowered, it can be easily lowered.

Also, when soil concrete hardens, its adhesive force E
Thus, the supporting force of the steel pipe 8 can be increased.

Furthermore, if the fill concrete is made of expandable material, the adhesion will increase even more.

By the way, the hardened material used once during excavation, which has a low compressive strength after hardening, only needs to ensure adhesion strength to the hollow pipe, so the compressive strength of the fill concrete may be about 30 kg/cTL.

On the other hand, soil concrete has a compressive strength of 150 k because the hardened material with high compressive strength after hardening requires completely closing the tips of the hollow pipes and strengthening the supporting ground.
g/cy? i, or more is desired.

An example of its formulation is as follows. Further, the calculated bearing capacity of this invention, the pre-poling method, and the 2-hole method is as follows.

This invention has the above-mentioned configuration, and the uncured soil concrete, which has a low compressive strength after hardening with a poor mix, has a complementary high fluidity compared to ordinary earth and sand.

Therefore, the positive resistance of the steel pipe is extremely small, and the construction time is shortened compared to one auger of the same capacity.

It is also possible to construct piles with larger diameters and longer lengths.

In addition, uncured soil concrete - white Maorgas screw 1
Since it does not stick to the ground, it is not discharged onto the ground like earth and sand, and the effect of improving workability is significantly better.

□In addition, in this construction method, in order to increase the supporting force in the vertical and horizontal directions, soil concrete is made one size larger than the steel pipe diameter to the required depth, one steel pipe is erected, and after it hardens, the steel pipe is and within.

In order to integrate the soil concrete outside, the soil and cement milk are stirred sufficiently during the first excavation, when inserting the steel pipe, and when pulling out the auger, so that the steel pipe and hardened soil concrete adhere well. integral f
This is synthesized.

In addition, the completed synthetic pile has a hardened layer of soil concrete formed on the inside and outside of the steel pipe, which provides a preservative effect to the steel pipe. The steel pipes are reinforced with high soil concrete, and the wall thickness of the steel pipes can be relatively thin, and the pipes float in close contact with the ground, preventing subsidence and providing sufficient support strength.

[Brief explanation of drawings]

1, 2, 3, 4, 5, and 6 are sectional views showing an outline of the construction process sequence. 1...Auger, 2...Hollow Rondo,
33'... Auger head, 4... Bit, 5... Spiral blade, 6... Stirring blade, 7
...Rotary drive device, 8... Steel pipe 29.
...Hardened material, 10... Protrusion.

Claims (1)

[Claims] 1. Using an auger, the ground is excavated to the required depth while injecting hardened material with low compressive strength after hardening. 1. Next, the auger is pulled up without stirring the ground soil and the hardened material. 1. Next, the hardened material is unhardened. In between, suspend the hollow tube into the borehole, insert an auger into the hollow tube, rotate it, and sink the hollow tube and auger to a predetermined depth, and insert the auger in advance of the hollow tube. , a construction method for foundation piles, which is characterized in that the lower end of the hollow pipe is hardened with a hardened material that has a high compressive strength after being injected, and the auger is pulled out without stirring the soil and hardened material inside the hollow pipe. .