JPS5841374B2 - Foundation pile stabilization method and device - Google Patents

Description

[Detailed description of the invention] TECHNICAL FIELD The present invention generally relates to pile foundation construction methods.

Conventional pile foundation construction methods include installing piles by directly hitting the head of the pile with a drop hammer or diesel hammer, and installing piles using the vibration and resonance force of a vibro hammer. method was used.

However, these construction methods involve noise and vibration pollution, which have become major social problems in recent years, so in recent years, after excavating the ground where the piles are to be installed, cement milk, etc. is poured into the construction method.
There, the cement milk injection method involves building piles, and inserting a screw auger etc. into the hollow part of the hollow pile, excavating the ground at the tip of the pile, and discharging the excavated soil through the hollow part of the pile. The medium excavation method, in which the material is sunk into the ground, has begun to be used.

Since these construction methods are vibration-free and noise-free construction methods, they contribute to resolving pollution problems. However, the former cement milk injection method requires each step of excavating the ground, pouring cement milk, and erecting piles. This method is not suitable for the recent trend toward longer piles, as the piles are not carried out at the same time, which requires a lot of construction time, and the walls of the borehole collapse, making it difficult to add thicker piles.

Secondly, in the latter method, the ground where the pile is installed is disturbed with an auger, etc., so the surface friction force between the outer circumference of the pile and the ground is lost, and the slime, which is the shavings of the excavated soil, is not sufficiently disposed of. However, the soil at the tip of the pile becomes soft due to the accumulation of slime, etc., and as a result, it has the disadvantage that sufficient bearing capacity cannot be expected compared to the impact method.

In addition, in recent years, the shaft of a screw auger has been used to inject a hardening agent such as cement milk from the tip of the auger, wrapping the tip of the pile in a bulbous shape and reinforcing the ground around the tip of the pile to increase its supporting capacity. Although efforts have been made to achieve this, no measures have been taken to recover the friction force on the pile's circumferential surface, and therefore the situation is still far from being able to say that the pile is installed stably.

It is an object of the present invention to provide a method for stabilizing foundation piles that eliminates the above-mentioned drawbacks, allows for relatively short construction time, and allows easy integration of the hard outer periphery and the ground using a hardening agent, and a device therefor. .

In order to achieve the above object, the present invention provides the following basic pile stabilization method and device.

(1) When carrying out the hollow excavation method, in which the ground corresponding to the tip of a hollow pile is excavated, the excavated soil is discharged through the hollow part of the pile, and the pile is sunk into the ground, a hardening agent injection device is used. A friction cutter attached to the outer periphery of the stiff tip of the pile cuts the frictional force between the outer periphery of the pile and the ground while the pile is being lowered, and when the pile reaches the specified position, the hardening agent A foundation pile characterized in that only the spouting device is pulled up in the longitudinal direction along the outer periphery of the pile, and the hardener is jetted from the hardener spouting device to fill the space between the outer periphery of the pile and the ground. Stability method.

(2) A friction cutter to be attached to the outer periphery of the tip of the hollow pile to be sunk, and a hardening agent that is housed in the friction cutter and can be removed from the friction cutter and moved in the longitudinal direction along the outer periphery of the pile. 1. A device for stabilizing a foundation pile, comprising a jetting device and a mechanism for moving the curing agent jetting device.

Next, embodiments of the present invention will be described below with reference to the drawings.

As shown in Figures 1, 5, 6, and 7, the friction cutter 1 includes an annular friction cutter body 2 that can fit around the outer periphery of the tip of a hollow pile P, and a flat plate portion 3 that comes into contact with the tip surface of the pile P. The friction cutter body 2 consists of
It has a hollow part 4 inside thereof, the upper part of the hollow part 4 is opened 5, and the lower part of the hollow part 4 is provided with a plurality of curing agent outlets 6 along the circumference of the annular body 2, and each of the outlets 6 is A valve 7 that can be opened only downward is pivotally attached to the lower surface by a pin 8.

The curing agent ejecting device 9 has an annular shape that can be accommodated in the hollow portion 4 from the upper opening 5 of the annular friction cutter body 2,
It has a hollow part 10 inside, and a plurality of curing agent spouts 11 are provided at equal intervals along the circumference at the lower part of the hollow part 10.
A curing agent injection port 1 is provided in the upper part of the cavity portion 10.
A curing agent injection hose 13 is provided at the injection port 12.
A suitable curing agent source (not shown) is connected to the upper end of the injection hose 13 .

The lower end of the wire 14 is connected to the upper part of the curing agent injection device 9, and the upper end of the wire 14 is connected to a suitable hoist 15.

Note that FIGS. 8 and 9 show modifications of the curing agent jetting device.

Next, the construction order of the method for stabilizing foundation piles according to the present invention will be explained below.

First, as shown in FIG. 1, the annular friction body 2 of the friction cutter 1, which houses the hardening agent injection device 9 in the hollow portion 4 of the friction cutter body 2, is inserted into the hollow peg P.
The flat plate part 3 of the friction cutter 1 is fitted onto the outer periphery of the tip of the hollow pile P, and the flat plate part 3 of the friction cutter 1 is placed against the tip surface of the hollow pile P, and the screw auger 17 having a bit 16 that can be opened and closed at the tip is inserted into the hollow part of the pile P. A pile P is built on the ground G, and while water is injected from the tip of the auger 17, the ground G corresponding to the tip of the pile P is excavated by the auger 17, and the excavated soil is discharged through the hollow part of the pile. is sunk into the ground.

During the pile sinking, the friction cutter 1 rests its flat plate portion 3 against the tip of the pile, so the friction cutter main body 2 is also pushed into the ground as the pile is sunk.
As a result, the ground around the outer circumference of the pile is pushed outward, and therefore no frictional force is generated between the outer circumference of the pile above the part where the friction cutter body 2 is attached, that is, the majority of the outer circumference of the pile, and the ground. , easily submerged.

Meanwhile, the valve 7 of the curing agent outlet 6 is closed by earth pressure.

Next, as shown in FIG. 2, when the peg P reaches a predetermined position, by pulling up the wire 14, the hardening agent injection device 9 is released into the hollow part of the friction cutter 1, as shown in FIG. The hardener M such as cement milk is pulled out from the opening 5 of the pile and pulled up in the longitudinal direction along the outer periphery of the stake, and the hardener M such as cement milk is jetted from the hardener spout 11 of the hardener jetter 9.

Meanwhile, the auger 17 is raised.

Next, when the hardening agent injection device is lifted to the ground, hardening agent M is filled between the outer periphery of the pile and the ground, as shown in FIG. 4, and the foundation pile is thus stabilized.

As can be understood from the above explanation, according to the present invention, the excavation of the ground and the erection of piles are carried out at the same time, and furthermore, the laying of piles is easily carried out, so the construction time is shortened, and the tip of the pile is The outer part of the pile and the part between the outer periphery of the pile and the ground are filled with a hardening agent to restore the frictional force on the peripheral surface of the pile, so that sufficient supporting force can be obtained.

Further, according to the present invention, the excavation of the ground that corresponds to the tip of the pile is
Prior to the pile installation, the ground will turn into muddy water.
The friction cutter body receives little ground resistance, and the piles can be easily sunk.

Furthermore, since the ground around the pile's periphery is excavated by the friction cutter body, high pressure is not required for the subsequent injection and filling of the hardening agent between the pile's outside periphery and the ground, so hardening agent injection pipes, etc. There is no need to use a metal tube; a rubber hose will suffice.

Furthermore, according to the present invention, since the friction cutter only has a structure for attaching to the tip of the stake,
The structure is simple, and since the curing agent injection device can be recovered, it can be used repeatedly and is economical as a whole.

In addition, for construction on soft ground, for example, the hole wall may collapse due to the soft ground surrounding the pile, and normally,
Even when it is impossible to fill the space between the outer periphery of the pile and the ground with the hardening agent, according to the present invention, the hardening agent ejecting device is raised to push up the collapsed soil and fill the space afterward with the hardening agent. be able to.

Furthermore, if the present invention is used in combination with the recent pile tip hardening method in the medium excavation method, it is possible to fill the entire area of the pile installation area with the hardening agent.

[Brief explanation of the drawing]

FIG. 1 is a partial vertical cross-sectional view of the ground, hollow pile, and friction cutter showing the situation during the first step of the foundation pile stabilization method according to the present invention, and FIG. FIG. 3 is a partial longitudinal cross-sectional view of the ground, hollow pile, and friction cutter showing the condition of the ground, hollow pile, and friction cutter, and FIG. FIG. 4 is a partial longitudinal sectional view of the soil, hollow pile, and friction cutter showing the situation after the foundation pile stabilization method is completed; FIG. FIG. 6 is a bottom view of the friction cutter, FIG. 6 is a partial vertical cross-sectional view of the hollow pile, friction cutter, and hardening agent jetting device, FIG. 7 is a partial vertical cross-sectional view of the same as above, and FIG. teeth,
FIG. 9 is a partial vertical cross-sectional view of a modification of the hardening agent jetting device, a hollow peg, and a friction cutter, and FIG. 9 is a longitudinal cross-sectional view of another modification of the hardening agent jetting device. DESCRIPTION OF SYMBOLS 1... Friction cutter, 4... Hollow part of friction cutter, 5... Opening of hollow part 4, 6... Curing agent outlet, 9...・・・・・・
Hardening agent jetting device, 14...Mechanism for moving the hardening agent jetting device, P...Hollow pile, G.
...Ground, M...Hardening agent.

Claims (1)

[Claims] 1. When carrying out the hollow excavation method in which the ground corresponding to the tip of a hollow pile is excavated, the excavated soil is discharged through the hollow part of the pile, and the pile is sunk into the ground, hardening is required. A friction cutter that houses the agent ejecting device and is attached to the outer circumference of the tip of the pile cuts the frictional force between the outer circumference of the pile and the ground while the pile is being set, and when the pile reaches the specified position. , characterized in that only the hardening agent jetting device is pulled up in the longitudinal direction along the outer periphery of the pile, the hardening agent is jetted from the hardening agent jetting device, and the hardening agent is filled between the outer periphery of the pile and the ground. A method for stabilizing foundation piles. 2. A friction cutter to be attached to the outer periphery of the tip of the hollow pile to be sunk, and a curing agent jet that is housed in the friction cutter and can be removed from the friction cutter and moved in the longitudinal direction along the outer periphery of the pile. 1. A device for stabilizing a foundation pile, comprising: a device; and a mechanism for moving the curing agent jetting device.