CN101397791A

CN101397791A - Pile-forming method of belled pile

Info

Publication number: CN101397791A
Application number: CNA200710157285XA
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 a two-stage enlarged-base pile. The pile forming method of the two-stage enlarged-base pile 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 formed by extrusion equipment, and all fine earth is thoroughly taken out; d. the immersed tube is pulled upward by a height H; e. an upper base space is formed by the extrusion equipment and all fine earth is taken out; f. steel bars are put into from an opening of the immersed tube; g. flowing concrete is poured; h. a recast pile body with dowels are put into from the opening of the immersed tube and anchored with the steel bars; and i. the immersed tube is pulled out, and concrete slurry is injected into the gap for forming pile. The construction method has the advantages and effects that the pile body diameter is small, and the bearing capacity can be designed very large, and the quality can be ensured through inspection, thus being applicable to the multi-base large-bearing-capacity pile.

Description

The piling method of expanded bore pile

Technical field

The present invention relates to the piling method of the secondary expanded bore pile of a kind of construction of building pile foundation engineering, particularly a kind of expanded bore pile.

Background technology

According to the national regulation whole body is cast-in-place expanded bore pile, i.e. pile body Cast-in-place concrete, and base also is a Cast-in-place concrete, its base diameter ratio maximum value 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 to exist and pile bottom sediment can't be cleaned out, and Zhejiang Province's standard is 0.24 discount, it is too big to give a discount, 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 problem that the present invention is directed to the prior art existence provides a kind of piling method of expanded bore pile, purpose be process rationally, guarantee pile quality, give full play to the utilization rate of the strength of materials, make bearing capacity of single pile higher, all the time be in work under the most economical state, reduction coefficient reaches 0.9-1.0, obviously improves the cost performance of stake, reaches the Expected Results of design.

Piling method 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, and get clean hack; D, pulling out the H distance on the immersed tube; E, expand the end with extrusion equipment and form upper base space, get clean hack; F, put into reinforcing bar from the immersed tube mouth; G, the mobile concrete of perfusion; H, put into precast pile, and dock with reinforcing bar with joint bar from the immersed tube mouth; I, extract immersed tube, and between the slit, inject cement paste, pile.

The concrete steps of getting clean hack among described operation c and the e 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 2-10 that pulls out distance H on the immersed tube among the described operation d and be base diameter doubly.

Also be included among the described operation e between two Up/down bases and extrude the triangle space that is the cross setting with extrusion equipment.

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

Compared with prior art owing to do protection and rely on immersed tube, precision, degree of safety, quality that the end is expanded in construction all improve greatly in the present invention, the more important thing is it can direct visual record see below whole work progresss; Because immersed tube prefabricated multistage under-reamed pile has adopted precast pile, steel pipe pile body and prefabricated pile body of answering in advance, these pile body diameters are little, and it is very big that bearing capacity can be done, and quality can be checked and guarantee, adapts to very much the large bearing capacity pile that a plurality of bases are arranged and uses.It is little to meet multistage under-reamed pile requirement pile body diameter fully, and bearing capacity is big, the requirement that quality requirement is high.In addition, in environmental protection, energy-conservation all significantly better than prior art.

Description of drawings

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

Among the figure 1, metal pile head; 2, immersed tube; H is 2-10 a times of base diameter; 4, lower bottom base; 5, be the crosswise triangle space; 6, reinforcing bar; 7, upper bed-plate; 8, precast pile; 9, joint bar.

The specific embodiment

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

The piling method of expanded bore pile of the present invention comprises following processing step:

A, as shown in Figure 1a sinks to the hardpan design elevation to the immersed tube 2 that has metal pile head 1; B, shown in Fig. 1 b, take out metal pile head; C, shown in Fig. 1 c, prop up disc shaping machine with hydraulic pressure and expand the end and form upper base space 4, 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; D, shown in Fig. 1 d, pulling out the H distance on the immersed tube 2, its H be base diameter 2-10 doubly; E, shown in Fig. 1 e, prop up disc shaping machine with hydraulic pressure and expand end formation upper bed-plate 7, inhaling indigenous equipment with air fetches 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, and props up the disc shaping machine extruding at the position between two bases 4,7 up and down with YEJ800 type hydraulic pressure and overlook and be triangle space 5 that crosswise is provided with the frictional resistance between increase pile body and the hardpan; F, shown in Fig. 1 f, put into reinforcing bar 6 from the immersed tube mouth; G, shown in Fig. 1 g, the perfusion concrete that flows; H, shown in Fig. 1 h, put into the precast pile 8 that has joint bar 9, and dock with reinforcing bar 6 from the immersed tube mouth; I, shown in Fig. 1 i, extract immersed tube, in pile body and mud layer slit, inject cement paste or after the inwall of immersed tube injects cement paste, extract immersed tube again, pile.

Claims

1, the piling method of expanded bore pile is characterized in that comprising the steps: 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, and get clean hack; D, pulling out the H distance on the immersed tube; E, expand the end with extrusion equipment and form upper base space, get clean hack; F, put into reinforcing bar from the immersed tube mouth; G, the mobile concrete of perfusion; H, put into precast pile, and dock with reinforcing bar with joint bar from the immersed tube mouth; I, extract immersed tube, and between the slit, inject cement paste, pile.

2, the piling method of expanded bore pile according to claim 1, the concrete steps that it is characterized in that getting among described operation c and the e 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 expanded bore 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 expanded bore pile according to claim 1, the 2-10 that it is characterized in that pulling out on the immersed tube among the described operation d distance H and be base diameter doubly.

5, the piling method of expanded bore pile according to claim 1 is characterized in that also being included among the described operation e triangle space that is the cross setting between two Up/down bases with the extrusion equipment extrusion.

6, the piling method of expanded bore pile according to claim 5 is characterized in that described extrusion equipment is that hydraulic pressure props up disc shaping machine.