JP3219993B2 - Piling method in pit structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of foundation work for construction and civil engineering, and more particularly, to a method of driving a new pile in an existing pit structure.

[0002]

2. Description of the Related Art In construction and civil engineering work, a new pile is installed in an existing pit structure (hereinafter simply referred to as pit 3) whose groundwater level 1 is higher than a floor surface 2 as shown in FIG. 4 needs to be cast. At this time, when a hole 7 is dug in the bottom plate 5 (often a concrete bottom) of the pit 3, groundwater 6 naturally springs out and wets the existing equipment and devices (not shown) in the pit 3. Or make them unusable or unusable. Therefore, conventionally, prior to the foundation work, lowering the groundwater level 1 (for example, taking water near the pit, taking measures not to return the groundwater, etc.) was performed, and the water level as shown by the broken line 8 in FIG. After confirming that the pit 3 had been formed, the floor surface 2 in the pit 3 was gradually drilled and the pile 4 was driven.

[0003]

However, if the work for lowering the groundwater level around the pile before drilling the pile driving position is carried out, the cost for water replacement and water treatment increases. However, there has been a problem that the entire foundation construction cost is high. In view of such circumstances, an object of the present invention is to provide a method in which a pile can be driven in a pit without performing a prior work for lowering the water level even in a pit having a groundwater level higher than the floor surface.

[0004]

Means for Solving the Problems In order to achieve the above-mentioned object, the inventor has made intensive studies to omit the work of lowering the groundwater level, and conceived of the use of pods. That is, the present invention provides a method for driving a pile into a pit structure having a groundwater level higher than the floor, wherein the pile has a top end higher than the groundwater level and an inner diameter of the pile at the pile driving position on the floor of the pit structure. A pile driving method in a pit structure, characterized in that a sheath having a diameter larger than the outer diameter is fixed and built, and a pile is driven after drilling the inside of the sheath. The present invention is also a method for driving a pile in a pit structure, wherein the inner diameter of the sheath is 1.5 times or more and 2.0 times or less the outer diameter of the pile.

According to the present invention, even if the groundwater level is higher than the floor surface and the groundwater springs up at the time of drilling, the groundwater falls within the sheath and the pile can be driven therein. As a result, stakeout is possible in the pit without leakage of groundwater.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be specifically described below with reference to FIGS. Inner diameter 7 as sheath tube 9
The pile driving method according to the present invention was implemented using a steel pipe having a length of 62 mm, a thickness of 7 mm, and a length of 4500 mm. At this time, the groundwater level 1 was at a level about 2000 mm higher than the floor of the pit 3, and a steel pipe having an outer diameter of 508 mm and a length of 25 m was used as the pile 4.

First, the sheath tube 9 was fixed to the concrete floor at the bottom of the pit with bolts 10 so as to surround the pile driving position. As shown in FIG. 3, this fixing was performed by providing a flange portion 11 on the sheath tube 9 and using 204 bolts 10 there. Further, in order to prevent water leakage from the sheath tube 9 into the pit 3, the flange portion 11 was covered with an epoxy putty material 12 for completeness.

[0008] Then, primary drilling was performed by a drilling machine (not shown) arranged above the sheath tube 9. In this primary drilling,
As shown in FIG. 2, the concrete floor 3 of the pit 3
About 100 mm thickness was left without drilling, and a hook 13 for removing the remaining portion 14 was attached (see FIG. 3).
The drilling operation was temporarily stopped, and water was injected into the hole 7 in the sheath until the ground water level 1 became the same level. And
Secondary drilling was performed again in the water, and at the final stage of drilling, the remaining portion 14 was pulled out to complete the hole 7.

The pile 4 was driven by placing a known pile driver (not shown) above the sheath tube 9 and repeatedly hitting the upper end of the pile. In the above embodiment, the drilling is divided into two times, primary and secondary, and the drilling amount after 9 sets of sheath pipes is dispersed to facilitate the entire drilling operation. Then, the above-mentioned hook 13 may be attached from the beginning of the drilling head to perform the full drilling. Further, water is injected into the sheath pipe 9 in order to prevent water from spurting and scattering due to the groundwater pressure 1 when the hole 7 penetrates in the secondary drilling. When the underground water pressure is not so high as compared with the height of the sheath 9, it is not always necessary to inject water. FIG. 1 shows the final state of the present invention. Although water remains in the gap between the sheath tube 9 and the pile 4 even after the pile driving is completed, the thickness may be designed in consideration of the corrosion amount of the steel pipe pile.

Further, in the present invention, the inner diameter of the sheath and the outer diameter of the pile are set to 1.5 times or more and 2.0 times or less.
If it is less than 1.5 times, the drilling work is difficult, and if it is more than 2.0 times, it is too wide and the work is wasted. In the present invention, a ceramic tube or a resin tube can be used without limiting the sheath tube to a steel tube, and the cross-sectional shape of the tube may not be circular.

[0011]

As described above, according to the present invention, even in a pit where the groundwater level is higher than the floor surface, piles can be driven in the pit without prior work of lowering the water level. . As a result, the prior work of lowering the groundwater level, which had been performed in the past, became unnecessary, and the cost of foundation work was reduced.

[Brief description of the drawings]

FIG. 1 is a view showing an example constructed by a pile driving method according to the present invention.

FIG. 2 is a diagram showing a situation in which a pile driving method according to the present invention is being performed.

FIG. 3 is a view showing another situation different from FIG. 3 in which the pile driving method according to the present invention is being performed.

FIG. 4 is a diagram showing a state of drilling by a conventional construction method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Groundwater level 2 Floor surface 3 Pit 4 Pile 5 Bottom plate 6 Groundwater 7 Hole 8 Dashed line 9 Sheath pipe 10 Bolt 11 Flange part 12 Epoxy putty material 13 Hook 14 Remaining part

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Fukuichi Kato 1-chome, Mizushima-Kawasaki-dori, Kurashiki-shi (No address) Inside Kawatetsu Techno Construction Co., Ltd. (56) References JP-A-48-21312 (JP, A) Hei 7-305351 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) E02D 13/04 E02D 7/00 E21B 7/00

Claims (2)

(57) [Claims] When a pile is driven into a pit structure having a groundwater level higher than the floor surface, the pile head is higher than the groundwater level and has an inner diameter outside the pile at the pile driving position on the floor surface of the pit structure. A method for driving piles in a pit structure, comprising fixing a sheath pipe having a diameter larger than the diameter of the pipe, piercing the inside of the sheath pipe, and then placing a pile. 2. The pile driving method in a pit structure according to claim 1, wherein the inner diameter of the sheath tube is 1.5 times or more and 2.0 times or less of the pile outer diameter.