CN101130965A

CN101130965A - Pile-forming method for three-level expanding bottom combined pile body

Info

Publication number: CN101130965A
Application number: CNA2007101572703A
Authority: CN
Inventors: 童乐天; 王国奋; 吴伟林; 郑新俊
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-09-29
Filing date: 2007-09-29
Publication date: 2008-02-27

Abstract

The piling process of three-stage under-reamed composite pile stem includes the following steps: 1. immersing immersed tube with metal pile head into hardpan to design elevation; 2. taking out the metal pile head; 3. forming the lower base space with under reaming apparatus, drawing upwards the immersed tube to the first designed distance, forming the middle base space and taking out soil, setting the prefabricated hollow pile stem with steel dowels in the lower end into the immersed tube, pouring concrete to form the lower base, the lower base and the lower pile stem; 4. drawing upwards the immersed tube to the second designed distance, forming the upper base space and pouring concrete to form the upper base; 5. setting the prefabricated upper pile stem with steel dowels in the lower end into the immersed tube and connecting the steel dowels to upper base; and 6. withdrawing the immersed tube and injecting cement mortar to the gap. The pile has high material strength utilizing rate and low cost.

Description

The piling method of third level bottom-expanded combined pile body

Technical field

The present invention relates to the piling method of a kind of construction of building pile foundation engineering, particularly a kind of third level bottom-expanded combined pile body.It is the job practices of the multistage base large bearing capacity of highrise building pile foundation engineering 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 piling method of third level bottom-expanded combined pile body, purpose is to improve the utilization rate and the reduction coefficient of the strength of materials, make single pile bearing capacity big, guaranteeing that pile foundation quality reaches the Expected Results of design, and can reduce cost.

The piling method of third level bottom-expanded combined pile body of the present invention, the immersed tube that it comprises following processing step: a, have a metal pile head sinks to hardpan to design elevation; B, taking-up metal pile head; C, with mechanical bottom-expanding equipment processing lower base space, on pull out immersed tube to setpoint distance H ₁, with mechanical bottom-expanding equipment processing center base space, with the hack in the peace and quiet base space of borrow equipment, the precast hollow pile body that the lower end has joint bar is lowered in the immersed tube, and the perfusion concrete waters and pours down, middle base reaches pile body down; D, on pull out immersed tube to the distance H of setting ₂, with mechanical bottom-expanding equipment processing upper base space, its hack falls in the precast hollow pile body, perfusion concrete cast upper bed-plate; E, the last precast pile that the lower end is had a joint bar are lowered in the immersed tube, and joint bar and upper bed-plate are anchored; F, extract immersed tube, outside pile body, inject cement paste in the slit.

The piling method of third level bottom-expanded combined pile body, the immersed tube that it comprises following processing step: a, have a metal pile head sinks to hardpan to design elevation; B, taking-up metal pile head; C, with mechanical bottom-expanding equipment processing lower base space, on pull out immersed tube to setpoint distance H ₁, with mechanical bottom-expanding equipment processing center base space, with the hack in the peace and quiet base space of borrow equipment, the precast hollow pile body that the lower end has joint bar is lowered in the immersed tube, and the perfusion concrete waters and pours down, middle base reaches pile body down; D, on pull out immersed tube to the distance H of setting ₂, with mechanical bottom-expanding equipment processing upper base space, its hack falls in the precast hollow pile body, perfusion concrete cast upper bed-plate; E is lowered to reinforcing bar and be anchored with upper bed-plate from immersed tube, with pile body on the concrete pouring; F), take out immersed tube.

Concrete steps with the hack in the peace and quiet base space of borrow equipment 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.

The mechanical bottom-expanding equipment of above-mentioned operation c and the usefulness among the d expands the end, and to process upper and lower base space concrete steps as follows: the mark that the detent rail pin of bottom-expanding equipment is aimed on the immersed tube mouth is lowered to immersed tube, start equipment after the equipment upper end is also fixedly positioning and expand the end, expand the end and be vertical earlier expand the end again level expand the end, when reaching, construction stops automatically after design is marked deeply, base cavity pocket is formed on the bottom, expanding the work of undercutting sharpener this moment reaches when designing base diameter, be that power rail reaches predetermined number of revolutions, expand end shoveling and finish, bottom-expanding equipment is hung out ground.

The setpoint distance H of described operation c and d ₁And H ₂Be base diameter 2-10 doubly.

Borrow equipment among the described operation c is to be used for pipe sinking prefabricated steel concrete club-footed pile to inhale indigenous equipment.

Last precast pile among the described operation e can replace with pile body on the cast-in-place notes steel concrete.

On immersed tube, pull out to setpoint distance H among the described operation d ₂Cement injection between precast hollow pile body and soil afterwards.

The present invention is compared with prior art owing to adopt immersed tube to do protection and rely on, and three bases and down pile body be cast-in-place notes steel concrete pile body, in to go up pile body be technical measures such as precast pile, and expand end precision height, accurate positioning good concentricity through the evidence construction; Base diameter and pile body diameter ratio can reach 3.5-5.0, and reduction coefficient can reach 0.9, obviously improve the utilization rate of the strength of materials, and it is little to satisfy multistage under-reamed pile requirement pile body diameter fully, and bearing capacity is big, the requirement that quality requirement is high; Not only eliminate the defective that prior art exists, but also reached the Expected Results of design; Can also reduce construction cost.

Description of drawings

Fig. 1 a-Fig. 1 b is the construction view of the embodiment of the invention 1 each operation.

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

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

The specific embodiment

Embodiments of the invention 1a-Fig. 1 b and Fig. 2 in conjunction with the accompanying drawings are described in detail.

Embodiment 1:

The piling method of third level bottom-expanded combined pile body of the present invention, the immersed tube 2 that comprise following processing step: a, has a metal pile head sinks to the hardpan design elevation; B, taking-up metal pile head; C, prop up a kind of processing lower base space 4 in the disc shaping machine with mechanical bottom-expanding equipment, explosive forming and YEJ-800 hydraulic pressure, on pull out immersed tube 2 to setpoint distance H ₁, processing center base space 5 is expanded the end with immersed tube prefabricated steel concrete and is inhaled indigenous equipment and get hack in the clean lower base space 4, and the precast hollow pile body 3 that the lower end is had a joint bar is lowered in the immersed tube 2 cast-in-place base, pile body, the middle bases down of pouring down of perfusion concretes; D, on pull out immersed tube 2 to the distance H of setting ₂, between the slit of precast hollow pile body 3 and soil, inject cement paste, with mechanical bottom-expanding equipment processing upper base space 6, the cleaning hack makes it to fall in the precast hollow pile body 3, existing pour concrete upper bed-plate; E, the solid or hollow precast pile 7 of going up that the lower end is had a joint bar are lowered in the immersed tube 2, and make joint bar and upper bed-plate anchor it under; F, extract immersed tube 2, outside pile body, inject cement paste, pile in the slit.The setpoint distance H of described operation c and d ₁And H ₂Be base diameter 2-10 doubly.Adopt the inventive method to make three grades of expanded bore piles, and the like can process the expanded bore pile of 4-20 level.

Embodiment 2:

Its operation a to d is identical with embodiment 1, and operation e is lowered to reinforcing bar 8 and be anchored with upper bed-plate from immersed tube 2, with pile body on the concrete pouring; F, taking-up immersed tube.

Claims

1. the piling method of third level bottom-expanded combined pile body is characterized in that it comprises following processing step: a, the immersed tube that has a metal pile head sinks to hardpan to design elevation; B, taking-up metal pile head; C, with mechanical bottom-expanding equipment processing lower base space, on pull out immersed tube to setpoint distance H ₁, with mechanical bottom-expanding equipment processing center base space, with the hack in the peace and quiet base space of borrow equipment, the precast hollow pile body that the lower end has joint bar is lowered in the immersed tube, and the perfusion concrete waters and pours down, middle base reaches pile body down; D, on pull out immersed tube to the distance H of setting ₂, with mechanical bottom-expanding equipment processing upper base space, its hack falls in the precast hollow pile body, perfusion concrete cast upper bed-plate; E, the last precast pile that the lower end is had a joint bar are lowered in the immersed tube, and joint bar and upper bed-plate are anchored; F, extract immersed tube, outside pile body, inject cement paste in the slit.

2. the piling method of third level bottom-expanded combined pile body according to claim 1, it is characterized in that the concrete steps with the hack in the peace and quiet base space of borrow equipment 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.

3. the piling method of third level bottom-expanded combined pile body according to claim 1, it is characterized in that the mechanical bottom-expanding equipment of above-mentioned operation c and the usefulness among the d expands in the end processing, the lower base space concrete steps are as follows: the mark that the detent rail pin of bottom-expanding equipment is aimed on the immersed tube mouth is lowered to immersed tube, start equipment after the equipment upper end is also fixedly positioning and expand the end, expand the end and be vertical earlier expand the end again level expand the end, when reaching, construction stops automatically after design is marked deeply, base cavity pocket is formed on the bottom, expanding the work of undercutting sharpener this moment reaches when designing base diameter, be that power rail reaches predetermined number of revolutions, expand end shoveling and finish, bottom-expanding equipment is hung out ground.

4. the piling method of third level bottom-expanded combined pile body according to claim 1 is characterized in that the setpoint distance H of described operation c and d ₁And H ₂Be base diameter 2-10 doubly.

5. the piling method of third level bottom-expanded combined pile body according to claim 1 is characterized in that the borrow equipment among the described operation c is to be used for pipe sinking prefabricated steel concrete club-footed pile to inhale indigenous equipment.

6. the piling method of third level bottom-expanded combined pile body according to claim 1 is characterized in that the last precast pile among the described operation e, can replace with pile body on the cast-in-place notes steel concrete.

7. the piling method of third level bottom-expanded combined pile body according to claim 1 is characterized in that pulling out on immersed tube to setpoint distance H among the described operation d ₂Cement injection between precast hollow pile body and soil afterwards.