CN101130959A

CN101130959A - Extruding pile-forming method for multilevel expanding bottom pile with high bearing capacity

Info

Publication number: CN101130959A
Application number: CNA200710157253XA
Authority: CN
Inventors: 王茂华; 吴伟林; 王国奋; 陈宁华; 郑新俊; 周亚萍
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-09-29
Filing date: 2007-09-29
Publication date: 2008-02-27

Abstract

The present invention relates to construction of building pile foundation engineering, and is especially extrusion piling process of multistage under-reamed pile with prefabricated pile foundation and great bearing capacity. The extrusion piling process includes the following steps: immersing immersed tube with metal pile head into hardpan, taking out the metal pile head, forming the lower base space and taking out soil, drawing upwards the immersed tube to designed distance, forming the upper base space and taking out soil, pouring the lower base with concrete and inserting steel dowels, setting the prefabricated pile stem, pouring the upper base with concrete, immersing the upper prefabricated pile stem into the immersed tube to connect the steel dowels of the lower prefabricated pile stem, withdrawing the immersed tube and injecting cement mortar to around the pile stem. The pile has small stem diameter, accurate location, high material strength utilizing rate and other advantages.

Description

The extrusion pile forming method of the multistage under-reamed pile of high bearing capacity

Technical field

The present invention relates to the extrusion pile forming method of the multistage under-reamed pile of a kind of construction of building pile foundation engineering, particularly a kind of high bearing capacity.Be the multistage under-reamed pile large bearing capacity, the job practices of precast pile Foundation Design first-selection.

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 multistage under-reamed pile of high bearing capacity, purpose makes full use of strength of materials utilization rate, improves reduction coefficient, the reliable degree height, base diameter and pile body diameter ratio are big and the accurate positioning precision is good, and single pile bearing capacity is big.

The extrusion pile forming method of the multistage under-reamed pile of high bearing capacity comprises following processing step: a, the immersed tube that has metal pile head is sunk to hardpan to design elevation; B, taking-up metal pile head; C, expand end processing lower base space, get clean hack with extrusion equipment; D, on pull out immersed tube to setpoint distance H; E, expand end processing upper base space, get clean hack with extrusion equipment; F, pour into a mould lower bottom base, be lowered to joint bar with concrete; G, put into the upper end from the immersed tube mouth and have the following precast pile of last joint bar; H, perfusion concrete cast upper bed-plate; The last precast pile that i, lower end have joint bar is lowered to immersed tube, and docks with the joint bar of following precast pile upper end; J, extract immersed tube, in pile body periphery slit, inject cement paste.

The extrusion pile forming method of the multistage under-reamed pile of high bearing capacity comprises following processing step: a, the immersed tube that has metal pile head is sunk to hardpan to design elevation; B, taking-up metal pile head; C, expand end processing lower base space, get clean hack with extrusion equipment; D, on pull out immersed tube to setpoint distance H; E, extrusion equipment expand end processing upper base space, get clean hack; F, pour into a mould lower bottom base, be lowered to joint bar with concrete; G, put into the upper end from the immersed tube mouth and have the following precast pile of last joint bar; The lower end of h, joint bar puts in upper base space, and the upper end puts in 1/3rd places in the pre-hollow pile body; I, go up the precast hollow pile body and be lowered to the immersed tube back that puts in place and upwards irritate concrete cast upper bed-plate and go up 1/3rd sections of precast hollow pile body lower ends in the precast hollow pile body mesopore, joint bar just is connected following precast pile, base anchoring with last precast hollow pile body and is integral like this; J, extract immersed tube, in pile body periphery slit, inject cement paste.

Described extrusion equipment is that hydraulic pressure props up disc shaping machine.

The concrete steps of getting clean hack among the above-mentioned 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.

Can also replace with positive crossover-circulating type method among the described operation c with extrusion equipment expansion end processing base.

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

Upper and lower precast pile among described operation g and the i is a kind of in precast hollow pile body, prefabricated solid pile body and the steel pipe pile body.

Last precast pile among the described operation i can replace with the compound pile body of going up of the steel pipe that cast-in-situ steel concrete in the immersed tube forms.

Last precast pile among the described operation i can inject the steel pipe composite pile body that existing pour concrete forms in immersed tube after the upper bed-plate with short joint bar and replace.

Described operation i and j can merge into the last precast hollow pile body that the lower end has joint bar, are lowered to the operation replacement of injecting cement paste or water glass in the slit behind the immersed tube between pile body and immersed tube inwall.

The present invention is compared with prior art owing to do protection and support with immersed tube; up and down pile body is a precast pile or to go up pile body be that technical measures such as steel pipe prefabricating composite pile body and technology thereof are reasonable in addition; and through evidence have pile body diameter little, with base diameter ratio big; accurate positioning; obviously improve strength of materials utilization rate; its reduction coefficient can reach 0.9-1.0 reliable degree height, and the supporting capacity of single pile can be done very greatly, this be prior art can't be obtained.

Description of drawings

Fig. 1 a-1h is the view of each operation construction of the present invention.

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

Among the figure 1, lower base space; 2, immersed tube; 3, upper base space; 4, go up joint bar; 5, following precast pile; 6, go up precast pile; 7, following joint bar; 9, long reinforcing bar.

The specific embodiment

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

Embodiment 1:

Shown in Fig. 1 a-1h is the per pass operation construction view of piling method of the present invention, comprises following processing step: a, the immersed tube 2 that has metal pile head is sunk to hardpan to design elevation; B, taking-up metal pile head; C, expand a kind of processing lower base space 1 in the end or the positive crossover-circulating type method, get clean hack with extrusion equipment; D, on pull out immersed tube 2 to setpoint distance H, its H be base diameter 2-10 doubly, the value size is relevant with factors such as base progression and pile body height; E, expand a kind of processing upper base space 3 in the end or the positive crossover-circulating type method with extrusion equipment, get clean hack, following pile body is the precast hollow pile body, hack can be swept in the precast pile to get final product; F, perfusion concrete cast lower bottom base insert joint bar; G, put into the solid time precast pile 5 that the upper end has last joint bar 4 from 2 mouthfuls of immersed tube; H, perfusion concrete cast upper bed-plate; The hollow precast pile 6 of going up that i, lower end have joint bar 7 is lowered in the immersed tube 2, and docks with the last joint bar 4 of following precast pile 5 upper ends, shown in figure li; J, extract immersed tube 2, in pile body periphery slit, inject cement paste.

Embodiment 2:

As shown in Figure 2, operation a to g is identical with embodiment 1, and operation h puts into immersed tube 2 with long reinforcing bar 9, and perfusion concrete cast upper bed-plate and cast-in-situ steel concrete and steel pipe are compounded to form pile body, pile.

Embodiment 3:

Operation a to h is identical with embodiment 1, and operation i forms Cast-in-place concrete and compound pile body, the pile gone up of steel pipe with pour into concrete after the short joint bar insertion upper bed-plate in immersed tube 2.This kind method is to be fit to adopt when the Up/down base diameter is all very big.

Embodiment 4:

Operation a to h is identical with embodiment 1, the last precast hollow pile body that operation i lower end has a following reinforcing bar 9 is lowered to the immersed tube back that puts in place and injects cement paste or water glass form pile body on steel pipe and precast pile compound between pile body and immersed tube, and this kind bearing capacity of pile and quality are the highest.

Embodiment 5:

Operation a to g is identical with embodiment 1, and the lower end of operation h joint bar puts in upper base space, and the upper end puts in 1/3rd places in the pre-hollow pile body; I, go up the precast hollow pile body and be lowered to the immersed tube back that puts in place and upwards irritate concrete cast upper bed-plate and go up 1/3rd sections of precast hollow pile body lower ends in the precast hollow pile body mesopore, joint bar just is connected following precast pile, base anchoring with last precast hollow pile body and is integral like this; J, extract immersed tube, in pile body periphery slit, inject cement paste.

Claims

1. the extrusion pile forming method of the multistage under-reamed pile 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 hardpan to design elevation; B, taking-up metal pile head; C, expand end processing lower base space, get clean hack with extrusion equipment; D, on pull out immersed tube to setpoint distance H; E, extrusion equipment expand end processing upper base space, get clean hack; F, pour into a mould lower bottom base, be lowered to joint bar with concrete; G, put into the upper end from the immersed tube mouth and have the following precast pile of last joint bar; H, perfusion concrete cast upper bed-plate; The last precast pile that i, lower end have joint bar is lowered to immersed tube, and docks with the joint bar of following precast pile upper end; J, extract immersed tube, in pile body periphery slit, inject cement paste.

2. the extrusion pile forming method of the multistage under-reamed pile of high bearing capacity according to claim 1 is characterized in that described extrusion equipment is that hydraulic pressure props up disc shaping machine.

3. the extrusion pile forming method of the multistage under-reamed pile of high bearing capacity according to claim 1, the concrete steps that it is characterized in that getting among the above-mentioned operation c clean hack 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 multistage under-reamed pile of high bearing capacity according to claim 1 is characterized in that can also replace with positive crossover-circulating type method with extrusion equipment expansion end processing base among the described operation c.

5. the extrusion pile forming method of the multistage under-reamed pile of high bearing capacity according to claim 1, it is characterized in that setpoint distance H among the described operation d be base diameter 2-10 doubly.

6. the extrusion pile forming method of the multistage under-reamed pile of high bearing capacity according to claim 1 is characterized in that upper and lower precast pile among described operation g and the i is a kind of in precast hollow pile body, prefabricated solid pile body and the steel pipe pile body.

7. the extrusion pile forming method of the multistage under-reamed pile of high bearing capacity according to claim 1 is characterized in that the last precast pile among the described operation i can replace with the compound pile body of going up of the steel pipe that cast-in-situ steel concrete in the immersed tube forms.

8. the extrusion pile forming method of the multistage under-reamed pile of high bearing capacity according to claim 1 is characterized in that the last precast pile among the described operation i can replace with the steel pipe composite pile body that existing pour concrete forms in immersed tube after the short joint bar reeve upper bed-plate.

9. the extrusion pile forming method of the multistage under-reamed pile of high bearing capacity according to claim 1, it is characterized in that described operation i and j can merge into the last precast hollow pile body that the lower end has joint bar, be lowered to the operation replacement of between pile body and immersed tube inwall, injecting cement paste or water glass in the slit behind the immersed tube.