JPH01131717A - Construction of in-situ pile - Google Patents

Abstract

PURPOSE:To construct an underground pile with good efficiency by a method an excavated pile pit is filled with mud water, reinforcement such as reinforcing bar cage, etc., and a concrete injecting pipe are inserted into the mud water, and concrete is placed into the pie while drawing up the injecting pipe. CONSTITUTION:While jetting fresh water from the tip of an auger rod tipped with a spiral blade, the auger rod is turned to excavate a pile pit 6. After the auger rod is drawn out, a reinforcing bar cage 8 and a concrete injecting pipe 9 are inserted into the mud water of the pit 6. While raising the pipe 9 gradually from the pile pit bottom, concrete 14 is poured by a pump 13 to construct a concrete pile 15 in the pit 6. Ready-mixed concrete can thus be placed with good efficiency on site.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a cast-in-place pile construction method for constructing concrete piles on-site.

(Conventional technology) Conventionally, when constructing concrete piles on site, for example, the planned pile driving position is excavated with a screw auger to form a pile hole, and then reinforcing materials such as rebar cages are placed inside the pile hole. ,
Furthermore, a tremie pipe is inserted into this pile hole.Next, a ready-mixed concrete truck parked near the pile hole is activated, and the ready-mixed concrete is sent from the ready-mixed concrete truck into this tremie pipe and dropped into the tremie pipe, and the ready-mixed concrete is poured into the pile hole. It is being poured.

(Problem to be Solved by the Invention) However, in the conventional method described above, when the diameter of the pile hole is large, sufficient self-weight drop can be achieved, but when the diameter of the pile hole becomes small, sufficient self-weight drop can be obtained. There is a problem that a falling effect cannot be obtained.

To explain this in detail, a reinforcing bar cage is placed inside the pile hole, and a tremie tube is inserted into this reinforcing bar cage, so if the pile hole diameter is about 700 au, the diameter of the tremie tube is 250 au. ~300 seagulls.

In the case of a tremie pipe with a smaller diameter, the contact friction between the inner surface of the pipe and the fresh concrete falling inside the pipe increases, which reduces the falling speed of the fresh concrete, which reduces the effect of concrete falling under its own weight. Therefore, the problem arises that the quality of concrete piles deteriorates.

Therefore, in the conventional method, the lower limit of the pile hole diameter is about 700 mm, and a sufficient concrete placing effect cannot be obtained with a pile hole having a diameter smaller than this.

Further, in the above method, since it is necessary to arrange a ready-mixed concrete truck near the pile hole, it is difficult to work in a narrow place, and there is also the problem of stones.

The basic purpose of this invention is to solve the above-mentioned problems, and it is possible to efficiently construct high-quality concrete piles even in narrow pile holes or in narrow work areas where ready-mixed concrete trucks cannot fit. This provides a pile construction method.

(Means for Solving the Problems) In order to achieve the above object, the present invention involves forming a pile hole by excavating a pile driving position, and then inserting reinforcing material and a concrete injection pipe into the pile hole. Inject the ready-mixed concrete into the pile hole using a pump through a transfer pipe connected to the pipe head, press the ready-mixed concrete sequentially from the bottom of the pile hole, lift the pipe from the pile hole, and place the ready-mixed concrete. This is a characteristic feature.

In addition, when forming the pile hole, it is also possible to inject mortar into the lower end of the pile hole to form a foot hardening section prior to press-fitting the fresh concrete.

Moreover, it is possible to use a reinforcing bar basket or a steel pipe as the above-mentioned reinforcing material.

In addition, if the diameter of the pipe is about 100In1, 3
It is suitable for application to pile holes having a diameter of about 00 to 600 mm. In addition, the length of the pile to be constructed is, for example, 10
~20m.

(Function) According to the present invention, fresh concrete is forced into the pile hole through the pipe by the pump, and concrete is placed reliably and efficiently. Therefore, it can be applied to a pile hole with a small diameter with the same effect. Also,
Since fresh concrete is transferred by a pump, it is not necessary to be close to the pile hole, and if it can be transferred by hose, it can be placed far away, so concrete can be placed efficiently even in a narrow work space.

(Example) An example of the present invention will be described below based on FIGS. 1 to 6.

First, the auger rod 1 is placed at a pile driving position to form a pile hole. This auger rod 1 has a spiral blade 2 formed on the tip side of the rod, and a digging blade 3 formed on the tip edge. Further, kneading drums 4 are provided on the rod above the spiral blade 2 at predetermined intervals, and plate-shaped stirring blades 5 are installed radially between the drums 4.4. The auger rod 1 is rotated and lowered to excavate the piling position. During this excavation, fresh water is injected into the excavated portion from the tip of the auger rod 1, if desired. The excavated earth and sand becomes mud, which is stirred by stirring blades 5 and kneaded onto the wall of the excavated hole by drum 4, forming a pile hole 6 having a diameter of, for example, 300 to 600 mm. A cylindrical casing 7 is inserted into the upper end of this pile hole 6. This casing 7 has a flange 7a formed on its upper edge, and by inserting the casing 7, mud clods near the ground surface can be removed. It is possible to prevent the pile hole 6 from falling into the pile hole 6 or the inner wall of the pile hole 6 from collapsing.

After forming the pile hole 6, cement milk is supplied from the lower end of the auger rod 1, and the mixture of residual earth and sand and cement milk is used to harden the roots.Then, the auger rod 1 is removed from the pile hole 6, and the auger rod 1 is removed from the pile hole 6. Insert and install the reinforcing bar cage 8 into 6. Note that it is also possible not to perform root hardening if desired.

Furthermore, at the center of the pile hole 6 and on the inner circumferential side of the reinforcing bar cage 8,
A concrete injection pipe 9 having a diameter of approximately 100 mm is inserted. A simple cover (not shown), such as tape, is provided on the tip edge of the concrete injection pipe 9 to prevent the mud in the pile hole 6 from penetrating inside. Since this simple lid generates buoyancy when the concrete injection pipe 9 is inserted into the pile hole 6, a counterweight (not shown) is provided at its lower end.

Note that one end of a hose 12, which is a transfer pipe, is connected to the head of the concrete injection pipe 9.
A pump 13 is connected to the other end of 2.

By the operation of the pump 13, the ready-mixed concrete 14 from a ready-mixed concrete storage unit (not shown) (such as a ready-mixed concrete truck) is sent into the pipe 9 through the hose 12.In the pipe 9, the ready-mixed concrete 14 comes into contact with the inner wall of the pipe 9, causing friction. However, since the fresh concrete 14 is forcibly injected by the pump 9, the fresh concrete 14 can be pumped through the pipe 9 regardless of this friction, and the fresh concrete 14 is poured from below the pile hole 6. will be established. After press-fitting a predetermined amount of fresh concrete 14 into the pile hole 6, the pipe 9 is pulled up to a predetermined length, and the pump 13 continues to operate.
Fresh concrete 14 is press-fitted from below. By repeating this process, the ready-mixed concrete 14 is pressed into the pile hole 6 and placed. By placing the ready-mixed concrete 14, the residual mud in the pile hole 6 is replaced with the ready-mixed concrete 14 and discharged outside the pile hole 6.

After finishing placing the fresh concrete 14, the pipe 9 is extracted from the pile hole 6, and the casing 7 is further extracted from the pile hole 6.

After this, the fresh concrete 14 hardens over time, so
Concrete piles 15 are efficiently constructed on site, concrete can be placed efficiently even in pile holes with a small diameter, and work efficiency is good, and high-quality piles can be obtained. In addition, concrete can be placed efficiently in cases where the specific gravity of the concrete and the residue in the pile hole is large, making it difficult to place concrete, or in cases where the length of the pile hole is short and the concrete's own weight cannot be fully utilized. It can be carried out.

In this embodiment, a reinforcing bar cage was used as the reinforcing material, but a steel pipe may also be used. In short, it is sufficient as long as it has the effect of reinforcing the concrete. Further, it is also possible to use as a reinforcing material a combination of different materials such that a high-strength steel pipe is located on the upper side of the pile, which is subject to strong bending stress, and a reinforcing bar basket is located on the lower side.

In the above embodiment, the foot protection part at the bottom of the pile hole was also made to have the same diameter as the pile hole, but the chain part may be enlarged to provide an expanded bottom foot protection part.

(Effects of the Invention) As explained above, according to the present invention, after forming a pile hole by excavating a pile driving position, a reinforcing material is placed in the pile hole, a pipe is inserted, and a pipe is inserted into the pipe. Ready-mixed concrete is injected by a pump through a transfer pipe connected to the pipe head, and the ready-mixed concrete is sequentially pressed into the pile hole from the lower part, the pipe is lifted, and concrete is poured, so piles can be constructed efficiently on site. Furthermore, even when constructing small-diameter piles, ready-mixed concrete can be placed efficiently, and a sufficient placing effect can be obtained. Because the concrete is placed under pressure, the concrete can be placed densely and quickly.

[Brief explanation of the drawing]

Figures 1 to 6 are schematic diagrams showing the implementation process of the present invention, where Figure 1 is a diagram during excavation, Figure 2 is a diagram of foot protection, Figure 3 is a diagram of the auger being pulled up, and Figure 4 is a diagram showing the state in which the auger is pulled up. The figure shows the concrete injection pipe inserted, Figure 5 shows the concrete injection pipe pulled up, and Figure 6 shows the concrete pile after it has hardened. 1... Auger rod 6... Pile hole 8... Rebar basket 9... Concrete injection pipe 12... Hose 13... Pump 14... Fresh concrete 15... Concrete pile

Claims (1)

[Claims] After excavating the pile driving position and forming the pile hole, reinforcing material and a concrete injection pipe are inserted into the pile hole, and fresh concrete is injected with a pump through the transfer pipe connected to the head of the pipe, and the concrete is poured into the bottom of the pile hole. A cast-in-place pile construction method characterized by pouring ready-mixed concrete into the pile hole sequentially from the beginning and placing the ready-mixed concrete by lifting the pipe.