CN101397784A

CN101397784A - Pile-forming method of immersed tube belled pile

Info

Publication number: CN101397784A
Application number: CNA2007101572440A
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 pile forming method of an immersed tube enlarged-base pile, which is a preferred construction method of a multi-stage base large-bearing-capacity pile. The pile forming method for the immersed tube enlarged-base pile of the invention comprises the following process steps: a. an immersed tube with a metal pile head is sunk to the a hard soil layer for designing elevation; b. the metal pile head is drawn out; c. a lower base space is formed, and excavated fine earth is thoroughly taken out; d. flowing concrete is put into from an opening of the immersed tube to the preset elevation L; e. the immersed tube is pulled upward to a preset height H; f. an earth bucket is put into from an opening of a self-immersed tube, an upper base space is formed mechanically, and the earth bucket is lifted out; g. flowing concrete is used for casting the upper base; h. a precast pile body with dowels are put into and anchored with the base; and i. the immersed tube is pulled out, and concrete slurry is injected into the gap. The construction method can greatly enhance the precision, the quality, and the safety performance for the enlargement of the base.

Description

The piling method of ram-expanded pile

Technical field

The present invention relates to the piling method of a kind of construction of building pile foundation engineering, particularly a kind of ram-expanded pile.It is the job practices of the big bearing peg first-selection of multistage base.

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 bearing capacity 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 present invention is directed to problem that prior art exists provide a kind of piling method of ram-expanded pile, purpose be make process rationally, guarantee the pile foundation engineering quality, obviously improve single pile bearing capacity, improve the strength of materials utilization rate, make stake in most economical state work with improve cost performance.

The piling method of ram-expanded pile of the present invention comprises following processing step: a, the immersed tube with 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, and get the hack that digs down only; D, put into the concrete that flows to calibrating high L from the immersed tube mouth; E, on pull out immersed tube to setpoint distance H; F, the mouth of pipe of drowning oneself are put into and are contained native well-bucket, expand end formation upper base space with extrusion equipment, will contain native well-bucket and propose; G, the mobile concrete cast of usefulness upper bed-plate; H, the precast pile and the base anchoring of putting into the band joint bar; I, extract immersed tube, and between the slit, inject cement paste, pile.

The concrete steps of getting clean 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.

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

The last plane that preset elevation L among the described operation d equals lower bottom base to the bottom surface of upper bed-plate deducts contains the high distance of native well-bucket.

Setpoint distance H among the described operation e equal base diameter 2-10 doubly.

Described precast pile is the precast hollow pile body.

Described precast hollow pile body is pile for prestressed pipe or solid pile body.

The present invention compared with prior art owing to adopt immersed tube to do protection and support, improves so precision, quality and the safety at the end are expanded in construction greatly; Owing to adopted these pile body diameters of precast pile little, it is very big that bearing capacity can be done, and guarantees the pile foundation engineering quality again, reach the Expected Results of design, its reduction coefficient can reach 0.9-1.0, be suitable at the bottom of the multistage expansion large bearing capacity pile foundation and use, this be prior art can't be obtained.This meets the requirement that multistage under-reamed pile body diameter is little, bearing capacity is big, quality requirement is strict fully.

Description of drawings

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

Among the figure, 2, immersed tube; 4, lower base space; H, equal base diameter 2-10 doubly; 5, mobile concrete; 6, contain native well-bucket; 7, upper base space; 8, precast pile; 9, joint bar.

The specific embodiment

Embodiments of the invention 1a-1g in conjunction with the accompanying drawings are described in detail.

The piling method of immersed tube two-stage expanded bore pile of the present invention comprises following processing step: a, the immersed tube 2 with 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 4, and get the hack that digs down only; D, put into the concrete 5 that flows to setting height L from the immersed tube mouth, the height that its L equals last plane to the bottom surface of upper bed-plate of lower bottom base deducts the distance of the height of the native well-bucket of Sheng; E, on pull out immersed tube 2 to the distance H of setting, the 2-10 that its H equals base diameter doubly, relevant according to the progression and the diameter of base, if multistage getting the small value, progression is few as have only the 2-3 level to get high value; F, the mouth of pipe of drowning oneself are put into and are contained native well-bucket 6, expand the end with extrusion equipment and make upper base space 7, promote afterwards and contain native well-bucket 6 to 2 mouthfuls of immersed tube; G, the mobile concrete 5 cast upper base space 7 of usefulness; H, put into the precast pile 8 of band joint bar 9, make joint bar 9 and upper bed-plate anchoring; I, extract immersed tube 2, in the slit, inject cement paste, pile.

Above-mentioned precast pile 8 is precast hollow pile bodies, as pile for prestressed pipe or solid pile body.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.

Secondary expanded bore pile with the inventive method is made has overcome the existing in prior technology defective fully, and intensity height, quality are guaranteed, and can obviously improve reduction coefficient, reduces the building foundation engineering cost, improves strength of materials utilization rate.So satisfy the requirement that multistage under-reamed pile requirement pile body diameter is little, bearing capacity is big, quality requirement is high fully.

Claims

1, the piling method of ram-expanded pile is characterized in that it comprises following processing step: a, the immersed tube with 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, and get the hack that digs down only; D, put into the concrete that flows to calibrating high L from the immersed tube mouth; E, on pull out immersed tube to setpoint distance H; F, the mouth of pipe of drowning oneself are put into and are contained native well-bucket, expand end formation upper base space with extrusion equipment, will contain native well-bucket and propose; G, the mobile concrete cast of usefulness upper bed-plate; H, the precast pile and the base anchoring of putting into the band joint bar; I, extract immersed tube, and between the slit, inject cement paste, pile.

2, the piling method of ram-expanded pile according to claim 1, the concrete steps that it is characterized in that getting among the described 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.

3, the piling method of ram-expanded pile according to claim 1 is characterized in that the extrusion equipment among described operation c and the e is that hydraulic pressure props up disc shaping machine.

4, the piling method of ram-expanded pile according to claim 1 is characterized in that last plane that preset elevation L among the described operation d equals lower bottom base to the bottom surface of upper bed-plate deducts to contain the high distance of native well-bucket.

5, the piling method of ram-expanded pile according to claim 1, it is characterized in that setpoint distance H among the described operation e equal base diameter 2-10 doubly.

6, the piling method of ram-expanded pile according to claim 1 is characterized in that described precast pile is the precast hollow pile body.

7, the piling method of ram-expanded pile according to claim 6 is characterized in that described precast hollow pile body is pile for prestressed pipe or solid pile body.