JPH07324330A - Pile driving construction method - Google Patents

Abstract

PURPOSE:To allow a ready-made pile with little settlement to be driven in without generating the obstruction of vibration and noise even in a place with a severe outskirt environmental condition such as an urban area and enable sufficient examination of soundness at the time of pile construction even in an on-site driven pile. CONSTITUTION:Tension material 4 bent in U-turn shape is inserted into a pile driving drilled hole 2 drilled in the ground 1. The tip part of the tension material 4 is fixed to a supporting layer at the lower part of the hole bottom, and the upper end part is led out of a hole port 2a. In this state, concrete 11 is placed in the drilled hole 2 to form a pile body 12. After the pile body 12 is sunk by previously applying a specified load to the pile body 12 by the tension material 4, the tension material 4 is pulled out and eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pile driving method.

[0002]

2. Description of the Related Art Conventionally, when constructing a building, the foundation design including piles must obey bearing capacity and settlement.

For this reason, in the case of a direct foundation, both are inevitably examined, but in the case of a pile foundation, the examination of settlement is often handled roughly by the consideration of bearing capacity alone. This was because it was thought that the pile would not support settlement if it was supported, and in fact the settlement caused by the building load.

Particularly in the case of ready-made piles in the embedded pile method, if a building is built without considering the settlement of the piles, uneven settlement will occur. Therefore, after the piles have been laid, generally, the pile head is tapped. Some subsidence is being done.

[0005] In addition, there are several points to be noted in the cast-in-place pile by the embedded pile method, such as slime treatment, and confirmation of the soundness of the pile is important, but in reality, it is almost nothing. However, non-destructive inspections are sometimes performed.

[0006]

However, the method of tapping the pile head after constructing the prefabricated pile by the embedded pile method as described above causes a vibration or noise obstacle in a place where the surrounding environmental conditions such as an urban area are severe. There was a problem that it occurred. For cast-in-place piles, non-destructive inspections to examine the soundness during pile construction were not always reliable.

The present invention has been made in view of the above problems, and an object thereof is to drive ready-made piles without generating vibrations or noise obstacles even in places with severe environmental conditions such as urban areas. It is also possible to provide a method for driving a pile, which is capable of sufficiently examining the soundness at the time of constructing a pile even for cast-in-place piles.

[0008]

[Means for Solving the Problems] In order to achieve the above-mentioned object, a pile driving method of the present invention is such that a tension material is inserted into a drilling hole for driving a pile, which is excavated in the ground, and a lower end portion thereof is bored. While fixing to the support layer at the bottom bottom, concrete is placed in the excavation hole in a state where the upper end of the pile is led out from the hole mouth to form a pile body, and a predetermined load is previously applied to the pile body by the tension member. The tension member is removed after the pile body is submerged by adding the load to the pile body, and the load applied in advance to the pile body is larger than the design load. It is to make a structure.

[0009]

[Advantage] According to the above construction, by pre-loading the pile body with the tension material, the ready-made pile by the embedded pile method can be generated without generating vibration or noise even in a place where the surrounding environmental conditions such as an urban area are severe. In addition to the above-mentioned effects, the soundness of the pile can be sufficiently checked because it can be subsided in advance and in the case of cast-in-place pile, it is the same as performing a load test for each pile. Further, by making the load to be applied in advance larger than the design load, it is possible to reduce the amount of subsidence of the pile due to the re-loading of the construction that is added after the tendon is removed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the cast-in-place driving method of the present invention will be described in detail below with reference to the drawings. 1 to 6 are cross-sectional views showing a method for driving a cast-in-place pile.

In the cast-in-place driving method, first, as shown in FIG. 1, a drilling hole 2 for driving a pile is excavated and formed in a predetermined place of a ground 1 where a building is constructed. And
At the bottom of the excavation hole 2, the tendon insertion hole 3 is excavated to the support layer or near the support layer.

Next, the tension member 4 bent in a U-turn shape is inserted into the excavation hole 2, and the U-turn portion 4a is inserted downward into the tension member insertion hole 3. In this case, a plurality of tendons 4 are inserted according to the diameter of the pile, but one excavation hole 3 or excavation depending on the number of tendons 4 can be performed. This tension member 4 is a PC as shown in FIGS. 7 and 8.
It is formed by covering the steel stranded wire 5 with a sheath 6 made of synthetic resin and filling a lubricant 7 such as grease between them, and is bent in a U-turn shape so as to be able to be pulled out after driving.

The lower end of the tension member 4, that is, U
The turn portion 4a is inserted into the tendon insertion hole 3 and the upper end of the turn portion 4a is led out from the hole opening 2a of the excavation hole 2.

Next, the lower end of the tension member insertion hole 3 is filled with grout 8 to form an anchor body 9, and the edge of the pile and the tension member 4 is formed in the tension member insertion hole 3 above the anchor body 9. In order to cut, the sand 10 is filled and the lower end of the tendon 4 is fixed.

Next, the reinforcing rod cage 13 is inserted into the excavation hole 2 and the concrete 11 is cast to form the pile body 12.
At this time, a spacer 13a is attached to the tension member 4 so that the tension member 4 is installed at the substantially central portion of the pile body 12.

After the concrete 11 is hardened and exhibits a predetermined strength, the upper end portion of the tension member 4 is tensioned with a tension jack to apply a load larger than the designed load to the pile body 12. Subside.

After applying a predetermined tension force to the tension member 4 in this manner, the upper end of the tension member 4 is fixed by the fixing metal fitting 14. Then, in this state, after the elapse of a predetermined period, the tendon 4 is pulled out from the anchor body 9 and removed. This removal is performed by pulling one of the PC steel strands 5 at the upper end of the tension member 4 bent in a U-turn shape.

When the tension member 4 is pulled out, the pile body 12
The subsidence does not change significantly because the ground rebound is small (see Fig. 9).

After preliminarily sinking the pile body 12 in this manner,
When the re-loading of the building is added to it, the amount of re-subsidence becomes the width shown in Fig. 9. The re-subsidence amount varies depending on the ground, but if the initial settlement is 50 mm, it will be 10 mm or less.

Then, after the pile body 12 is subsided as described above, the upper foundation is constructed to construct the upper structure.

Further, ready-made piles by the embedded pile method are also driven by the same method as described above.

[0022]

EFFECTS OF THE INVENTION A state in which a tension member is inserted into an excavation hole for driving a pile formed in the ground to fix the lower end portion to a support layer below the hole bottom and the upper end portion is led out from the hole mouth. After placing concrete in the excavation hole to form a pile body,
A predetermined load is applied to the pile body in advance with the tension material to sink the pile body to a predetermined depth, and then the tension material is removed, so that vibration or vibration can be generated even in a severe environment condition such as an urban area. It is possible to give the pile an initial settlement that is almost the same as when it was built without causing noise interference.

Since the load is applied to the pile body by the tension member, an arbitrary load can be applied accurately and efficiently by freely controlling the tension force.

By making the load pre-applied to the pile body after construction larger than the design load, it is possible to reduce the amount of re-subsidence of the pile body when a re-load is applied by the building load.

Further, in the case of cast-in-place pile, the same as carrying out a load test for each pile, the soundness of the pile can be sufficiently checked.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an excavation hole excavated in the ground.

FIG. 2 is a cross-sectional view of an excavation hole in which a tendon insertion hole is provided at the bottom of the hole bottom.

FIG. 3 is a cross-sectional view of an excavation hole in which a tension member is fixed to a tension member insertion hole.

FIG. 4 is a cross-sectional view of a pile body formed by placing concrete in an excavation hole.

FIG. 5 is a cross-sectional view of a pile body to which a load is applied by a tension member.

FIG. 6 is a cross-sectional view of the pile body from which the tension material is removed.

FIG. 7 is a cross-sectional view of a tendon.

FIG. 8 is a front view of a tension member.

FIG. 9 is a relationship diagram between a load and a subsidence amount.

[Explanation of symbols]

 1 Ground 2 Drilling Hole 3 Tensile Material Insertion Hole 4 Tensile Material 5 PC Steel Stranded Wire 6 Sheath 7 Lubricant 8 Grout 9 Anchor 10 Sand 11 Concrete 12 Pile 13 Reinforcing Bar Cage 14 Anchorage

Claims (2)

[Claims] 1. A state in which a tension material is inserted into an excavation hole for driving a pile excavated in the ground to fix the lower end portion to a support layer at the lower part of the hole bottom and the upper end portion is led out from the hole mouth. It is characterized in that concrete is poured into the excavation hole to form a pile body, and the pile body is sunk by applying a predetermined load to the pile body in advance with the tension material, and then the tension material is removed. Pile driving method. 2. The pile driving method according to claim 1, wherein a load applied in advance to the pile body is larger than a design load.