JPH03286020A - Method for driving cast in place concrete pile - Google Patents

Abstract

PURPOSE:To accelerate construction without using a special excavator or producing spoil by boring a hole into the ground up to a required depth by means of a vibrating rod with a shaker and then, while pulling out the rod, injecting stabilizing liquid into the hole. CONSTITUTION:A vibroflot 1, surface feeder type, with a shaker is hung on a three point support type tower 2, positioned at a boring place, given a horizontal vibration, and driven into the ground 3 up to a prescribed depth. After that, stabilizing liquid 5 such as betnight muddy water, is injected into a hole 4 through an injection pipe 6 from the tip of the vibroflot 1, while pulling out the vibroflot 1. After pulling out the vibroflot 1 from the hole 4, a reinforcement cage 7, tension reinforcing member, is suspendedly put into the hole 4 by the tower 2. In addition, a slime disposal is made through a tremie pipe 9, injecting further water by a water injection pipe 8, and concrete 11 is cast, pulling out the tremie pipe 9 with the drainage of the stabilizing liquid 5, to fill the hole 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cast-in-place concrete pile construction method, which is a type of pile foundation construction method.

[Conventional technology] Conventionally, this type of cast-in-place concrete pile construction method
For example, the Benotoe method (all casing method), the earth drill method, the reverse method (reverse circulation method), and other construction methods are known.

The all-casing construction method excavates the inside of the casing using a hammer grab while pushing the casing into the ground.
This method involves excavating the ground to the required depth, suspending reinforcing bars into the casing, and then pulling out the casing while pouring concrete.

In the earth drilling method, a pile hole is drilled by rotating a packet attached to the tip of an extensible rotating shaft called a Kelly bar, and after drilling to the required depth while pouring water to protect the hole wall, reinforcing bars are suspended. , is a method of pouring concrete.

In addition, the reverse method involves rotating a drill bit attached to the tip of a drill rod to drill a pile hole, and continuously discharging the excavated earth and sand using a reverse circulation method while protecting the hole wall with natural mud. This construction method involves excavating to a deep depth, suspending reinforcing bars, and pouring concrete.

Another cast-in-place concrete pile construction method is to excavate a pile hole with an earth auger, then pull out the earth auger while injecting a stabilizing liquid (bentonite slurry, etc.) into the hole from the tip of the earth auger, and suspend the reinforcing bars. Using the method of pouring concrete (in Italy) or the Deebvibro method, which is a type of lot compaction pile method, a pile hole is drilled by vibration of a rod, and then a material supply vibrator installed along an extension pipe is used to drill the hole. This is a construction method (West Germany) that makes simple piles by injecting mortar inside and pulling out the rods.

[Problems to be Solved by the Invention] However, the conventional Benoto construction method, earth drill construction method, and industrial reverse construction method have the following problems.

(1) Requires special excavation equipment.

(2) Excavated soil is generated, which is troublesome to dispose of.

(3) Excavation speed is slow and construction efficiency is poor.

On the other hand, in the construction method known in Italy, the above (2)
In addition, in the construction method known in West Germany, the completed piles have sufficient strength against vertical loads, but because the reinforcing bars are not manned, they cannot withstand tensile forces. They are weak and extremely brittle against horizontal loads, making it almost impossible to support structures as piles in Japan, where earthquakes occur frequently.

SUMMARY OF THE INVENTION Therefore, the present invention aims to provide a cast-in-place concrete pile construction method that does not require a special excavator, does not cause soil removal, has a high construction speed, and can improve the vertical and horizontal strength of the pile. .

[Means for Solving the Problems] In order to solve the above-mentioned problems, the cast-in-place concrete pile construction method of the present invention includes a method that includes a vibrating device to perform drilling performed prior to suspending tensile reinforcing material or placing concrete. This is a construction method in which stabilizing fluid is injected into the hole while the rod is pulled out after reaching the required depth in the ground by vibration of the rod.

[Function] In the above means, drilling is performed by penetration by vibration of a rod equipped with a vibration device, and collapse of the hole wall is prevented by injecting a stabilizing liquid when drilling the bow, and the rod at the time of drilling is The vibrations force the ground around the pile hole to become compacted.

Other sections are used.

It is customary to apply slime treatment before concrete is poured.

Rods equipped with a vibration device include those that generate horizontal vibrations using a vibration device at the lower end, such as the vibroflot used in the vibroflotation method;
Alternatively, a vibro hammer used in the vibro hammer construction method, which generates vertical vibration using an excitation device at the upper end, may be used, and the diameter of the rod may be constant over the entire length, or the diameter of the rod may be set to a larger diameter at the lower end. You can also use it as

As the stabilizing liquid, bentonite mud and other liquids are used.
As the injection means, a hollow portion of the rod or a pipe extending along the rod is used.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

First, a safety feed type Vibroflot 1 was used as a rod equipped with a vibrating device, and it was suspended from a three-point support tower 2 and positioned at the drilling location (see Figure 1 (a).
) After that, the vibroflot 1 was penetrated to a required depth of the ground 3, for example, to the support layer 3a, by horizontal vibration caused by the operation of the vibration excitation device (see FIG. 1(b)). This penetration of Vibroflot 1 forcibly compacted the surrounding ground.

Next, while pulling out the vibroflot 1, a stable liquid 5 such as bentonite mud was injected into the hole 4 created by the penetration from the tip of the vibroflot 1 through the inside of the vibroflot 1 (Fig. 1 (C)). reference). By injecting this stabilizing liquid 5, collapse of the hole wall was prevented even if the ground to be drilled was sandy ground or soft and viscous ground.

In addition, when pulling out the vibroflot 1, the hole diameter may be expanded by vertically moving the vibrating device while operating it (see FIG. 1(d)).

After removing the pipe flot 1 from the hole 4, the reinforcing bar cage 7, which is a tensile reinforcing material, is inserted into the hole 4 using the three-point support tower 2.
(See Figure 1 (e)), and while pouring water using the water injection vibrator 8, use the tremie tube 9 to treat the slime (see Figure 1 (f)). At the same time as the stabilizing liquid 5 was drained, concrete 11 was poured using the tremie pipe 9 while being pulled up (3
(See Figure 41 (g)). Then, fill-in was performed (see Fig. 1 (h)) to obtain cast-in-place concrete piles with a constant diameter (0.8 to 1.0 m in diameter and 30 m in length).

In addition, in the above embodiment, the case where the three-point support type tower 2 is used as the tower for suspending the vibroflot 1 was described, but it is not limited to this, and for example, a suspended type, a suspended leader type Other types of towers may also be used.

Furthermore, the rod equipped with the vibration device is not limited to the Vibroflot 1, which generates vibrations in the horizontal direction, but may also be a rod that generates vibrations in the vertical direction, such as a vibrohammer. The diameter is not limited to a fixed diameter, and the lower end may have a larger diameter.

Injection of the stabilizing liquid 5 is not limited to the so-called suface feed type that uses the hollow part of the vibroflot 1, but may also be of the so-called bottom feed type that uses a liquid injection vibrator along the vibroflot 1.

The reinforcing bar cage 7 may be suspended not only before the concrete 11 is placed, but also after the concrete 11 is placed and before it hardens.

In addition, the obstructive reinforcing member is not limited to the reinforcing bar cage 7, but also H-shaped steel,
■Shaped steel or other shaped steel may be used.

[Effects of the Invention] As described above, according to the present invention, drilling is performed by penetration due to the vibration of a rod equipped with a vibrating device, and collapse of the hole wall is prevented by injecting a stabilizing liquid when the rod is pulled out. Unlike the conventional all-casing construction method, earth drill construction method, and reverse construction method, this method does not require a special excavator, does not cause soil removal, and can speed up construction.

Furthermore, since the ground around the pile hole is forcibly compacted by the vibration of the rod during drilling, the vertical and horizontal strength of the pile can be improved, which is extremely economical.

[Brief explanation of drawings]

The figures show one embodiment of the present invention, and FIGS. 1(a) and 1(b)
). (c), (d), (e), (f), (
g) and (h) are longitudinal sectional views showing each step of the cast-in-place concrete pile construction method. 1... Piper Flot 3... Ground 3a...
Support layer 4...hole 5...stabilizing liquid
6...Reinforced cage 11...Concrete

Claims (1)

[Claims] (1) After drilling a hole prior to suspending tensile reinforcing material or placing concrete to the required depth in the ground by vibration of a rod equipped with an excitation device, stabilize liquid is poured into the hole while pulling out the rod. A cast-in-place concrete pile construction method characterized by injecting.