CN111424664A

CN111424664A - Construction method for removing pile head of pre-fractured bored pile

Info

Publication number: CN111424664A
Application number: CN202010306341.7A
Authority: CN
Inventors: 陈岩; 董光; 吕涛; 李振兵; 王振东; 杨胜楠; 李恒旭; 安宝石; 赵一山; 高峦; 高鑫; 李成
Original assignee: China Railway No 9 Group Co Ltd; Seventh Engineering Co Ltd of China Railway No 9 Group Co Ltd
Current assignee: China Railway No 9 Group Co Ltd; Seventh Engineering Co Ltd of China Railway No 9 Group Co Ltd
Priority date: 2020-04-17
Filing date: 2020-04-17
Publication date: 2020-07-17

Abstract

The invention relates to a construction method for removing a pile head of a pre-fractured bored pile, which comprises the following steps of: 1) the outer side of the reinforcement cage is annularly and fixedly connected with an annular expansion box; 2) the concrete pouring is completed to reach a final setting state; 3) the annular expansion box expands, the volume of the annular expansion box is increased, and the upper surface and the lower surface of the expansion box generate contact pressure; 4) the pile head and the pile body are broken under the expansion action of the expansion box. Annular expansion box is installed to pile head position steel reinforcement cage outside hoop in the pile foundation construction, and the expansion of expansion box makes the pile head fracture, reaches abolish pile head purpose, convenient operation, and the time limit for a project is short, reduces the risk index.

Description

Construction method for removing pile head of pre-fractured bored pile

Technical Field

The invention relates to a construction method, in particular to a construction method for removing pile heads of pre-fractured bored piles.

Background

In bridge construction, a pile foundation form is the most common structural form at present, and a construction method commonly adopted in pile head breaking construction is a manual pneumatic pick chiseling method at present. Cutting the pile top of the pile foundation, chiseling the concrete of the reinforcing steel bar protection layer along the cutting line by using an air pick, stripping all reinforcing steel bars at the position of the pile head, drilling holes around the pile head by using an electric drill, and expanding the pile head by using an expanding device such as an expanding drill or a splitting machine to insert into the holes to break the pile head by using a crane to lift the pile head, wherein the analysis shows that the existing construction method mainly has the following defects:

1) the cost is high: pile head chiseling needs the manual work to use the hoop cutting machine to cut in pile head position round, and the manual work uses the pneumatic pick to chisel the protective layer concrete, punches in pile head department with drilling equipment, uses expansion equipment to expand absolutely with the pile head, and during the construction, need drop into manual work, small-size machines are more, and the cost is higher.

2) The construction period is long: after the pile head is excavated, the whole construction process is time-consuming and labor-consuming due to the full manual chiseling in the construction link, the whole pile head needs one person for construction for 1-2 days, and the construction period is seriously influenced if the number of the pile heads on site is large and the number of air compression equipment is insufficient.

3) The quality is low: because the pile head adopts the manual chiseling mode, the end face of the pile head is easy to be irregular in the construction process.

4) The safety risk is high: the traditional construction method needs more manpower and small-sized machines, and equipment such as an air compressor, an air pick, a hoop cutting machine, a hydraulic expansion drill rod, a splitting machine and the like has certain risks in the use process.

Disclosure of Invention

The invention aims to solve the technical problem of providing a construction method for removing the pile head of a pre-fractured bored pile.

In order to solve the above problems, the specific technical scheme of the invention is as follows: a construction method for removing pile heads of pre-fractured bored piles comprises the pile heads, wherein reinforcement cages are arranged on the pile head parts, and the steps are as follows: 1) the outer side of the reinforcement cage is annularly and fixedly connected with an annular expansion box; 2) completing initial strength setting of concrete pouring; 3) the annular expansion box expands, the volume of the annular expansion box is increased, and the upper surface and the lower surface of the expansion box generate contact pressure; 4) the pile head and the pile body are broken under the expansion action of the expansion box.

The outer circumference of each steel bar of the steel bar cage of the pile head part is sleeved with a pvc pipe. The pvc pipe prevents the steel bar from being bonded with the concrete.

When the annular expansion box is a slow expansion type expansion box, a water-swelling adhesive tape is placed in the slow expansion type expansion box, and the annular expansion box expands to 2-3 times of the original volume within 72 hours after meeting water.

The annular expansion box is a timing expansion box, a static explosive and a water-full plastic pipe are arranged in the timing expansion box, a resistance wire is fixed on the pipe wall, and the electric wire of the resistance wire is connected to the pile head. After the concrete reaches a final setting state, an expansion reaction is triggered before pile detection, the resistance wire is electrified, the plastic pipe is heated and melted, water in the plastic pipe is in contact with an expansion agent to react, the volume is rapidly increased, and huge contact pressure is generated by expansion, so that a pile head and a pile body are pulled to break.

The invention has the following beneficial effects: 1. the cost is saved; 2. the construction speed is improved, and the construction period is saved; 3. the construction quality is improved, and the end face of the pile head is smooth; 4. and the construction safety factor is improved.

Drawings

Fig. 1 is a schematic diagram of a pile foundation structure.

Fig. 2 is a schematic diagram of a pile foundation structure provided with an expansion box.

Fig. 3 is a structural schematic diagram of the annular expansion box.

Fig. 4 is a schematic diagram of the internal structure of the annular expansion box.

Fig. 5 is a resistance connection circuit diagram.

Detailed Description

As shown in fig. 1 to 5, a construction method for removing a pile head of a pre-fractured bored pile includes a pile head 1, a reinforcement cage is arranged at the part of the pile head 1, and the steps are as follows: 1) the outer side of the reinforcement cage is annularly and fixedly connected with an annular expansion box 2; 2) completing initial strength setting of concrete pouring; 3) the annular expansion box 2 expands, the volume is increased, and the upper surface and the lower surface of the expansion box generate contact pressure; 4) the pile head 1 and the pile body are broken under the expansion action of the expansion box.

The outer circumference of each steel bar of the steel bar cage of the part of the pile head 1 is sleeved with a pvc pipe 3.

When the annular expansion box 2 is a slow expansion type expansion box, a water-swelling adhesive tape is placed in the slow expansion type expansion box, the water-swelling adhesive tape expands to 2-3 times of the original volume within 72 hours after meeting water, and the water-swelling adhesive tape expands within 72 hours after concrete pouring is completed to generate huge surface contact pressure, so that the pile body and the pile head 1 are broken in a tensile manner, and the purpose of breaking the pile head 1 is achieved.

When the annular expansion box 2 is a timing expansion box, a static explosive and a water-full plastic pipe 2-1 are arranged in the timing expansion box, a resistance wire 2-2 is fixed on the pipe wall, an electric wire of the resistance wire 2-2 is connected to the pile head 1, when concrete reaches a final setting state, an expansion reaction is triggered before pile detection, the resistance wire 2-2 is electrified, the plastic pipe 2-1 is heated and melted, water in the pipe is in contact with the static explosive to react, the volume is rapidly increased, and huge contact pressure is generated by expansion, so that the pile head 1 and the pile body are pulled to break.

What has been described above is merely a preferred embodiment of the invention. It should be noted that variations and modifications can be made by those skilled in the art without departing from the principle of the present invention, and they should also be considered as falling within the scope of the present invention.

Claims

1. The utility model provides a pre-fracture drilling pile head gets rid of construction method, includes the pile head, and pile head part is equipped with the steel reinforcement cage, its characterized in that following step: 1) the outer side of the reinforcement cage is annularly and fixedly connected with an annular expansion box; 2) completing initial strength setting of concrete pouring; 3) the annular expansion box expands, the volume of the annular expansion box is increased, and the upper surface and the lower surface of the expansion box generate contact pressure; 4) the pile head and the pile body are broken under the expansion action of the expansion box.

2. The pile head removing construction method of the pre-fractured bored pile according to claim 1, comprising: the outer circumference of each steel bar of the steel bar cage of the pile head part is sleeved with a pvc pipe.

3. The pile head removing construction method of the pre-fractured bored pile according to claim 1, comprising: the annular expansion box is a slow expansion type expansion box, a water-swelling adhesive tape is placed in the slow expansion type expansion box, and the annular expansion box expands to 2-3 times of the original volume within 72 hours after meeting water.

4. The pile head removing construction method of the pre-fractured bored pile according to claim 1, comprising: the annular expansion box is a timing expansion box, a static explosive and a plastic pipe filled with water are arranged inside the timing expansion box, an electric heating resistance wire is fixed on the wall of the plastic pipe, an electric wire of the electric heating resistance wire is connected to the pile head, the resistance wire is electrified during a triggering reaction, the plastic pipe is heated and melted, water in the pipe reacts with the expansion agent, the volume is rapidly increased, and the expansion agent is expanded until the pile head is broken.