CN101397781A

CN101397781A - Extrusion pile-forming method of belled prefabricated pile body with high bearing ability

Info

Publication number: CN101397781A
Application number: CNA2007101572402A
Authority: CN
Inventors: 王国奋
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-09-29
Filing date: 2007-09-29
Publication date: 2009-04-01

Abstract

The invention relates to a construction method for building pile foundation engineering, in particular to a extrusion pile forming method a high-bearing-capacity enlarged-base precast pile body. The pile forming method of the invention comprises the following process steps: a. an immersed tube with a metal pile head is sunk to a hard soil layer for designing elevation; b. the metal pile head is drawn out; c. a lower base space is processed by base enlarging equipment and the sunk tube is drawn upward to a preset height H, and an upper base space is processed and fine earth is thoroughly sucked by an earth sucking device; d. a lower precast hollow pile body with dowels at the lower end is connected with an upper precast hollow pile by steel bars and laid down from an opening of the immersed tube to the right position; e. concrete is poured from a center hole of the pile body to cast an upper base and a lower base; and f. the immersed tube is pulled out, and slurry is poured into the gap. The construction method has the advantages and effects of high utilization rate of the material strength, and the strength reduction can reach 0.9 to 1.0.

Description

The extrusion pile forming method of the bottom-enlarging prefabricated pile body of high-bearing capacity

Technical field

The present invention relates to the piling method of a kind of construction of building pile foundation engineering, particularly a kind of bottom-enlarging prefabricated pile body.

Background technology

According to the national regulation whole body be cast-in-place (be the pile body Cast-in-place concrete, base also is a Cast-in-place concrete) its base diameter ratio maximum value of expanded bore pile is limited in 3-3.5, and pipe sinking prefabricated steel concrete club-footed pile, this stake is the prefabricated concrete of pile body, the base Cast-in-place concrete, obviously this ratio 3-3.5 is broken, generally 3.5-5 can be reached,, requirement of engineering can't be satisfied although bearing capacity is bigger, particularly, the opposite end bearing capacity to give a discount 0.9 when bellout diameter during greater than 1.5 meters.For this reason, immersed tube prefabricated multistage under-reamed pile has appearred again.Existing multiple bearing capacity dish stake technology has two common ground, and first all is to expand the end with positive crossover-circulating type method pore-forming; Second all carries out pile without immersed tube expands the end.This two point-to-points load dish (at the bottom of the multistage expansion) stake is quite unfavorable, in other words, bring two problems, 1), national building code requirement, expand the base end load at the end with positive crossover-circulating type method pile and will take advantage of 0.45 coefficient, because have mud existence and pile bottom sediment to clean out, (Zhejiang Province's standard is 0.24 discount) gives a discount too big, though a plurality of bases are arranged, loss end load is very big; 2); without immersed tube; condition of construction can not get protection; positive in addition crossover-circulating type method is operation under water; expand bottom application worker situation and cannot see, the difficult measurement noted down, when also usually taking place to expand the end under water; top soil body a slice situation that falls down also happens occasionally; also have because the multistage stake of prior art all is the whole body Cast-in-place concrete, and that the intensity of Cast-in-place concrete is done is not high, and difficult quality guarantee; and in water, water concrete; the difficult control of quality adds that the pile capacity of a plurality of bases is all bigger, and its pile body diameter of above factor must be done greatlyyer; and this a plurality of base is afraid of that pile body diameter is big most; development test shows that pile body diameter increases, and its bearing capacity decay is very serious.

Summary of the invention

The problem that the present invention is directed to the prior art existence provides a kind of extrusion pile forming method of bottom-enlarging prefabricated pile body of high-bearing capacity, purpose is to improve the utilization rate and the reduction coefficient of the strength of materials, make bearing capacity of single pile higher, make that base diameter and pile body diameter ratio are big to reach the expected design effect fully.

The extrusion pile forming method of the bottom-enlarging prefabricated pile body of high-bearing capacity of the present invention comprises following processing step:

A, the immersed tube that has metal pile head is sunk to the hardpan design elevation; B, taking-up metal pile head; C, expand the end with extrusion equipment and form lower base space, on pull out immersed tube to setpoint distance H, expand the end with extrusion equipment and form upper base space, inhale indigenous equipment exhaustion hack; D, the following precast hollow pile body that the lower end is had a joint bar put down until putting in place with the mouth of pipe of drowning oneself after last precast hollow pile body links to each other by reinforcing bar; E, pour into concrete, water and pour down upper bed-plate from the mesopore of pile body; F, extract immersed tube, between the slit, inject cement paste.

The extrusion pile forming method of the bottom-enlarging prefabricated pile body of secondary high-bearing capacity comprises following processing step:

A, the immersed tube that has metal pile head is sunk to the hardpan design elevation; B, taking-up metal pile head; C, expand the end with extrusion equipment and form lower base space, on pull out immersed tube to setpoint distance H, expand the end with extrusion equipment and expand the end and form upper base space, inhale indigenous equipment exhaustion hack; D, pour into concrete cast lower bottom base from the immersed tube mouth; E, the following prefabricated solid pile body 8 that the lower end is had a joint bar 7 insert in the immersed tube 2 until putting the cast upper bed-plate in place by reinforcing bar 6 back that links to each other with last precast hollow stake 4; F, extract immersed tube 2, between the slit, inject cement paste.

Extrusion equipment among the described operation c is that hydraulic pressure props up disc shaping machine.

The concrete steps of exhaustion hack are as follows among the described operation c: inhale indigenous equipment with air and fetch earth, when only surplus a small amount of loosing during soil in the base, from immersed tube mouth pouring, pouring limit, limit sops up, and is clean up to fetching earth.

Setpoint distance H among the described operation c is 2-10 a times of base diameter.

The present invention is compared with prior art owing to do protection and support with immersed tube; and adopt technical measures such as precast hollow combined pile body; and through its strength of materials utilization rate height of evidence; reduction coefficient can reach 0.9-1.0; the ratio of base diameter and pile body diameter surpasses state-set standard, and the single pile bearing capacity height obviously reduces the pile foundation engineering cost; reaching the Expected Results of design fully, is the preferred job practices of multistage base large bearing capacity pile.

Description of drawings

Fig. 1 a-1e is each operation status of processes schematic diagram of the present invention.

Fig. 2 is the master operation construction view of another embodiment of the present invention.

Among the figure 1, lower base space; 2, immersed tube; 3, upper base space; 4, go up the precast hollow pile body; 5, following precast hollow pile body; 6, reinforcing bar; 7, joint bar; 8, prefabricated solid pile body.

The specific embodiment

Embodiments of the invention are described in detail in conjunction with the accompanying drawings.

Embodiment 1:

Extrusion pile forming method as the bottom-enlarging prefabricated pile body of Fig. 1 a-Fig. 1 e high-bearing capacity of the present invention comprises following processing step:

A, the immersed tube 2 that has metal pile head 1 is sunk to the hardpan design elevation; B, taking-up metal pile head; C, expand the end with extrusion equipment and form lower base space 1, on pull out immersed tube 2 to setpoint distance H, expand the end with extrusion equipment and form upper base space 3, with inhaling indigenous equipment exhaustion hack; D, the following precast hollow pile body 5 that the lower end is had a joint bar 7 put down until putting in place from 2 mouthfuls of immersed tube by reinforcing bar 6 back that links to each other with last precast hollow pile body 4; E, pour into concrete, water and pour down upper bed-plate from the mesopore of pile body; F, extract immersed tube 2, between the slit, inject cement paste.

Embodiment 2:

Operation a to c is identical with embodiment 1.As shown in Figure 2, operation d pours into concrete cast lower bottom base from the immersed tube mouth; The following prefabricated solid pile body 8 that operation e has the lower end joint bar 7 inserts in the immersed tube 2 until putting the cast upper bed-plate in place by reinforcing bar 6 back that links to each other with last precast hollow stake 4; Operation f extracts immersed tube 2, injects cement paste between the slit.

Setpoint distance H described in embodiment 1 and the embodiment 2 is 2-10 a times of base diameter.

Extrusion equipment among the operation c described in embodiment 1 and the embodiment 2 is that hydraulic pressure props up disc shaping machine.The concrete steps of exhaustion hack are as follows among the operation c described in embodiment 1 and the embodiment 2: inhale indigenous equipment with air and fetch earth, when only surplus a small amount of loosing during soil in the base, from immersed tube mouth pouring, pouring limit, limit sops up, and is clean up to fetching earth.

The pile foundation engineering of the inventive method manufacturing is eliminated the existing in prior technology defective fully, owing to adopted precast pile, these pile body diameters are little, and it is very big that bearing capacity can be done, and quality can check and guarantee, be particularly suitable for multistage expansion at the bottom of large bearing capacity pile use.

Claims

1, the extrusion pile forming method of the bottom-enlarging prefabricated pile body of high-bearing capacity is characterized in that it comprises following processing step: a, the immersed tube that has metal pile head is sunk to the hardpan design elevation; B, taking-up metal pile head; C, expand the end with extrusion equipment and form lower base space, on pull out immersed tube to setpoint distance H, expand the end with extrusion equipment and form upper base space, inhale indigenous equipment exhaustion hack; D, the following precast hollow pile body that the lower end is had a joint bar put down until putting in place with the mouth of pipe of drowning oneself after last precast hollow pile body links to each other by reinforcing bar; E, pour into concrete, water and pour down upper bed-plate from the mesopore of pile body; F, extract immersed tube, between the slit, inject cement paste.

2, the extrusion pile forming method of the bottom-enlarging prefabricated pile body of high-bearing capacity according to claim 1 is characterized in that the extrusion equipment among the described operation c is that hydraulic pressure props up disc shaping machine.

3, the extrusion pile forming method of the bottom-enlarging prefabricated pile body of high-bearing capacity according to claim 1, the concrete steps that it is characterized in that exhaustion hack among the described operation c are as follows: inhale indigenous equipment with air and fetch earth, when only surplus a small amount of loosing during soil in the base, from immersed tube mouth pouring, pouring limit, limit sops up, and is clean up to fetching earth.

4, the extrusion pile forming method of the bottom-enlarging prefabricated pile body of high-bearing capacity according to claim 1, it is characterized in that setpoint distance H among the described operation c be base diameter 2-10 doubly.