JPS5857576B2 - Pile foundation construction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for constructing a pile foundation, and in particular a noiseless and vibrationless method for constructing a pile foundation, in which a hole is excavated underground using muddy water, and a foundation pile is reliably placed in the hole. This invention relates to a pile foundation construction method suitable for driving-in-place piles in urban areas.

Conventionally, various pile foundation construction methods have been proposed and developed in response to social demands for eliminating noise and vibration pollution when constructing foundation piles for buildings in urban areas.

One of these methods is the cast-in-place pile method, in which a hole is excavated in the ground by various means and then concrete or the like is poured at the construction site.

Furthermore, this method of driving piles in place includes, as a method particularly suitable for the above-mentioned anti-pollution measures, a method in which muddy water is used to excavate into the ground with a hammer club or the like, and a foundation pile is constructed in the hole.

According to this method, the slime that has accumulated at the bottom of the hole is removed using an air lift, etc., but it is not possible to confirm whether the slime has been completely removed or not, and as a result, there are concerns about the strength of the foundation pile. There is a drawback.

Another pile foundation construction method is the deep foundation method.

In this method, workers drill a hole in the ground while installing retaining material, then install reinforcing bars and pour concrete. Although it is possible to check the condition at the bottom of the excavation, According to this method, if the ground in which the hole is to be excavated is sandy soil, there is a drawback that the construction is hindered by sand boiling.

In addition, among the deep foundation construction methods, a mechanical method in which the hole wall is supported entirely by a casing, the hole is excavated with a hammer grab, the slime accumulated at the bottom of the hole is disposed of by a worker, and concrete, etc. is poured while pulling out the casing. There is a deep foundation construction method, but even with this method, if the ground is sandy soil, the construction will be hindered by boiling, and if the layer of sandy soil is thick, it will be difficult to pull out the casing. If the casing is not pulled out, the disadvantage is that the increased amount of casing used increases costs.

Furthermore, the mechanical deep foundation construction method uses a casing that is divided into small pieces because the casing is press-fitted with jacks, but according to this method, it is necessary to take measures to prevent water leakage from the joints between the divided casings. Moreover, in order to withstand press-fitting by jacks, thin-walled steel pipes or the like cannot be used as foundation pile members, resulting in an overall high construction cost.

Therefore, an object of the present invention is to reliably dispose of the slime deposited at the bottom of the hole when drilling a hole in the ground using a mud drilling method and constructing a foundation pile in the hole, and to ensure that the slime that accumulates at the bottom of the hole is properly treated. To provide a noiseless and vibrationless method for constructing a pile foundation, which can be applied to a wide range of ground without restrictions, and can be constructed at low cost overall by using thin-walled steel pipes as foundation piles.

The present invention basically involves drilling a hole in the ground using a stabilizing liquid, installing a tubular body in the hole, and then installing the tubular body in order to protect the hole wall and support the tubular body. The stabilizing liquid surrounding the tubular body outside the tubular body is solidified in the hole without solidifying the stabilizing liquid inside the tubular body, and then the stabilizing liquid inside the tubular body is discharged to the outside of the hole. The slime deposited on the bottom of the hole inside the tubular body is removed, and it is confirmed whether the slime deposited on the bottom of the hole has been properly removed by an operator who descends to the bottom of the hole through the inside of the tubular body. , after confirming that the slime has been properly removed, concrete is poured inside the tubular body to construct a pile foundation.

The features of the invention will become more apparent from the following description of the illustrated embodiment.

First, referring to FIG. 1, a hole 10 is excavated into the ground while being filled with a stabilizing liquid such as bentonite slurry to prevent collapse of the hole wall.

Next, a tubular body 12 made of a steel pipe is vertically built into the hole 10.

A precast concrete pipe may be used as the tubular body 12.

Further, as the tubular body 12, a steel pipe may be used in which the diameter of the distal end gradually increases in order to increase the supporting area of the distal end.

Thereafter, a chemical solution is injected into the ground near the bottom of the hole 10 as needed.

Thereby, for example, when the ground near the bottom of the hole 10 is made of sandy soil and the groundwater level is high, it is possible to make it impermeable and increase the supporting strength.

However, if the ground near the bottom of the hole 10 is impermeable clayey soil or a gravel layer with high support strength, it is not necessary to inject the chemical solution.

Furthermore, this chemical solution may be injected after solidification of the stabilizing liquid 11, which will be described later.

Thereafter, the stabilizing liquid 11 which is external to and surrounds the tubular body 12 is solidified within the bore 10 .

The stabilizing liquid 11 is solidified by, for example, adding a solidifying agent mainly composed of cement and sodium silicate to the stabilizing liquid in the hole and stirring and mixing.

In addition, when mixing the stabilizing liquid 11 and the solidifying agent, the stabilizing liquid 11 is mixed into the hole 1.
This can also be done during circulation between the 0 and an above-ground mixing plant (not shown).

The solidified product 14 (FIG. 2) of the stabilized liquid 11 thus obtained forms an underground wall that is integral with the tubular body 12, protects the hole wall, supports the tubular body, and supports the vertical arrangement of the tubular body. ensure that

Next, the stabilizing liquid 11 inside the tubular body 12 is discharged to the outside of the hole 10 by an air lift or the like.

After that, the inside of the tubular body 12 from which the stabilizing liquid 11 was discharged is drilled with a hole 1.
Lower the worker to the bottom of the 0.

At this time, the operator confirms whether or not slime has been deposited at the bottom of the hole 10 due to excavation.

Furthermore, if slime is deposited on the bottom, the slime is removed by the operator.

Thereafter, concrete 15 is placed only at the tip inside the tubular body 12.

When the tubular body 12 is a thin-walled steel pipe, this concrete 15 is poured over the entire interior of the tubular body 12.

The tubular body 12 constitutes a pile foundation integrally with the concrete 15, and resists external loading force together with the tip ground.

According to the method for constructing a pile foundation according to the present invention, when placing a tubular body as a foundation pile member underground, a hole is excavated using a muddy drilling method and the tubular body is built in the hole, rather than by hammering. Because the tube is filled in, almost no noise or vibration is generated, and thin-walled steel pipes can be used as the tubular body, reducing construction costs.Furthermore, since the stabilizing liquid surrounding the tubular body is solidified outside the tubular body, , the vertical arrangement of the tubular body can be ensured without being restricted by the soil quality of the ground near the hole.

Furthermore, since the present invention injects a chemical solution near the bottom of the excavated hole, the strength of the ground near the bottom can be increased, and it can be widely applied without being restricted by the soil quality of the ground. .

According to the present invention, as described above, since the presence or absence of residual slime can be directly confirmed by the worker, slime can be reliably removed, and thereby a pile foundation with sufficient bearing capacity can be constructed. .

Further, the stable liquid inside the tubular body to be removed is not solidified and is discharged out of the hole in a liquid state, so that the operation of discharging the stable liquid can be performed extremely easily and quickly.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a state in which a tubular body is built into a hole filled with a stabilizing liquid in the method for constructing a pile foundation according to the present invention, and FIG. It is a sectional view showing a state in which a pile foundation is constructed by pouring concrete into the tip after removing the internal stabilizing liquid. 10... Hole, 11... Stabilizing liquid, 12.
...Tubular body, 14...Solidified material, 15 Concrete.

Claims (1)

[Claims] 1. Excavating a hole in the ground using a stabilizing liquid, building a tubular body into the hole, and manufacturing the tubular body without solidifying the stabilizing liquid inside the tubular body. solidifying the stabilizing liquid surrounding the tubular body in the pore; discharging the stabilizing liquid inside the tubular body to the outside of the pore; removing slime deposited at the bottom of the pore inside the tubular body; After confirming that the slime deposited at the bottom of the hole has been properly removed by the worker descending to the bottom of the hole through the inside of the body, A method of constructing pile foundations that consists of placing concrete inside the pile. 2. Excavating a hole in the ground using a stabilizing liquid, erecting a tubular body in the hole, and removing the stabilizing liquid outside the tubular body without solidifying the stabilizing liquid inside the tubular body. solidifying a stabilizing liquid surrounding the tubular body within the hole; injecting a chemical into the ground near the bottom of the hole before or after the stabilizing liquid outside the tubular body solidifies; and discharging the stabilizing liquid inside the tubular body out of the hole. discharging, and removing the slime deposited at the bottom of the hole inside the tubular body, and checking whether the slime deposited at the bottom of the hole was properly removed by an operator descending to the bottom of the hole through the inside of the tubular body. A method of constructing pile foundations that consists of confirming that the slime is properly removed, and then pouring concrete inside the tubular body. 3. Claim 1, wherein the tubular body is a thin-walled steel pipe.
The pile foundation construction method described in Section 2. 4. The pile foundation construction method according to claims 1 and 2, wherein the tubular body is a precast concrete pipe. 5. The pile foundation construction method according to claim 1.2.3, wherein the concrete is placed over the entire area inside the tubular body. 6. Claim L2, characterized in that the concrete is placed only at the tip portion inside the tubular body.
, 4. Pile foundation construction method 7. The pile foundation construction method according to claims 1 and 2, wherein the tubular body is a steel pipe, and the steel pipe has a diameter that gradually increases at its tip. . 8. The pile foundation construction method according to claims 1 and 2, wherein the stabilizing liquid is solidified by adding and stirring a solidifying agent mainly composed of cement and sodium silicate.