阅读说明：本技术 一种用于珊瑚砂地基的灌注桩成孔和侧壁注浆施工方法 (Bored concrete pile hole forming and side wall grouting construction method for coral sand foundation ) 是由 朱艳 林靖 李小军 宣庐峻 高加云 宣以飞 肖炳辉 于 2019-09-11 设计创作，主要内容包括：本发明公开了一种用于珊瑚砂地基的灌注桩成孔和侧壁注浆施工方法,其特点是采用振动与静压交替作业的方法进行灌注桩套管成孔的施工,在拔出钢套管的同时进行桩侧注浆,具体施工包括：成孔、吊放钢筋笼和注浆套管、二次清孔、灌注桩浇筑、拔出钢套管和侧壁注浆等步骤。本发明与现有技术相比具有成桩可靠性和桩基承载力高,有效减少土体扰动,降低颗粒压碎度,提高桩侧摩阻力,较好的解决了珊瑚砂地基中成孔难和侧阻力低的问题,钢套管能够循环利用,大大降低了工程造价,绿色、环保,具有良好的环保效益和推广前景。(the invention discloses a bored concrete pile hole-forming and side wall grouting construction method for coral sand foundation, which is characterized in that the construction of bored concrete pile casing pipe hole-forming is carried out by adopting a vibration and static pressure alternative operation method, pile side grouting is carried out while a steel sleeve is pulled out, and the concrete construction comprises the following steps: the method comprises the steps of pore forming, steel reinforcement cage hoisting and grouting casing pipe hanging, secondary hole cleaning, cast pile pouring, steel casing pipe pulling, side wall grouting and the like. Compared with the prior art, the invention has the advantages of high pile forming reliability and pile foundation bearing capacity, effectively reducing soil disturbance, reducing particle crushing degree, improving pile side frictional resistance, better solving the problems of difficult hole forming and low side resistance in the coral sand foundation, recycling the steel sleeve, greatly reducing engineering cost, being green and environment-friendly, and having good environmental protection benefit and popularization prospect.)

1. The utility model provides a bored concrete pile pore-forming and lateral wall slip casting construction method for coral sand foundation, its characterized in that adopts the method of vibration and static pressure alternate operation to carry out the steel casing pipe pore-forming construction of bored concrete pile, along with the transfer of steel reinforcement cage, pre-buried slip casting sleeve pipe, when extracting the steel casing pipe, puts into the slip casting pipe and carries out the stake side slip casting in the pre-buried slip casting sleeve pipe, and concrete construction includes following step:

a. bored concrete pile pore-forming

adopting a vibration and static pressure alternative operation method, driving the steel sleeve into a coral sand foundation by using a telescopic static pressure device, digging out sandy soil in the steel sleeve by using water flushing after hole forming, and cleaning holes by using water instead of sand;

b. Steel bar placing cage

After the cast-in-place pile is formed, hoisting a reinforcement cage and a pre-buried grouting sleeve in a steel sleeve, and performing secondary cleaning on sediments;

c. Pouring pile-forming

Pouring concrete from bottom to top after secondary hole cleaning;

d. side wall grouting

and when the strength of the cast-in-place pile reaches 70%, opening the grouting sleeve, extending the grouting pipe into the bottom of the grouting sleeve, removing the steel sleeve at a constant speed, grouting the side wall of the cast-in-place pile from bottom to top at a constant speed until the steel sleeve is completely pulled out, and maintaining the cast-in-place pile after taking out the grouting pipe.

2. a method for forming a hole and grouting a side wall of a bored pile for coral sand foundation as claimed in claim 1, wherein said grouting pipe is terminated with a slant pipe having a multi-headed grouting nozzle with an inclination α of not less than 15 °.

Technical Field

The invention relates to the technical field of pile foundation engineering, in particular to a bored pile hole-forming and side wall grouting construction method suitable for a coral sand foundation.

Background

With the needs of national defense construction and the development and utilization of resources such as marine oil gas, fishery, tourism and the like, the number of coral island reef construction projects is increased day by day, the scale is enlarged day by day, and the requirement on the bearing capacity of the foundation is higher and higher. The cast-in-place pile is used as a deep foundation with wide applicability on land, and has great difficulty in island reef construction. The coral reef foundation mainly comprises coral sand, reef limestone, calcareous soil and coral clastic soil, wherein the coral sand (also called calcareous sand) has the characteristics of loose particles, high porosity, large apparent friction angle, easiness in crushing, strong discreteness of soil property and the like, and the construction technology of the ordinary slurry wall-protecting bored pile is easy to collapse, and the bearing capacity of the pile is different from that of prefabricated piles of the same specification. The precast pile faces to various problems such as difficult marine transportation and difficult boulder driving. Therefore, the method provides guarantee for designing and building infrastructure on the island, and has strong practical value for researching the hole forming and side wall grouting processes of the cast-in-place pile.

Disclosure of Invention

The invention aims to design a bored concrete pile hole forming and side wall grouting construction method for coral sand foundation aiming at the defects of the prior art, which adopts a vibration and static pressure alternative operation method to carry out the steel sleeve hole forming construction of the bored concrete pile, carries out pile side grouting while pulling out the steel sleeve, effectively reduces the soil disturbance, reduces the particle crushing degree, improves the pile side frictional resistance, greatly improves the stability of the hole wall and the bearing capacity of a pile foundation, better solves the problems of sand compaction and slow driving caused by a single vibration method and low difficulty and side resistance in the coral sand foundation, can recycle the hole forming steel sleeve, greatly reduces the engineering cost, and is green, environment-friendly and good in economical efficiency.

The purpose of the invention is realized as follows: the utility model provides a bored concrete pile pore-forming and lateral wall slip casting construction method for coral sand foundation, its characteristics are that the steel casing pipe pore-forming construction of bored concrete pile is carried out to the method of adopting vibration and static pressure alternative operation, along with the transfer of steel reinforcement cage, pre-buried slip casting sleeve pipe, when extracting the steel casing pipe, with slip casting pipe put into pre-buried slip casting sleeve pipe and carry out the stake side slip casting, concrete construction includes following step:

a. Bored concrete pile pore-forming

The method adopts a vibration and static pressure alternative operation method, a telescopic static pressure device is utilized to drive the steel sleeve into the coral sand foundation, after the hole is formed, sand in the steel sleeve is removed by water flushing, and the hole is cleaned by replacing sand with water.

b. Steel bar placing cage

After the cast-in-place pile is formed into a hole, a steel reinforcement cage and a grouting sleeve are hung in the steel sleeve, and secondary cleaning of sediments is carried out.

c. Pouring pile-forming

And (5) pouring concrete from bottom to top after secondary hole cleaning.

d. Side wall grouting

And when the strength of the cast-in-place pile reaches 70%, opening the grouting sleeve, extending the grouting pipe into the bottom of the grouting sleeve, removing the steel sleeve at a constant speed, grouting the side wall of the cast-in-place pile from bottom to top at a constant speed until the steel sleeve is completely pulled out, and maintaining the cast-in-place pile after taking out the grouting pipe.

The end part of the grouting sleeve is an inclined pipe of a multi-head grouting nozzle, and the inclination angle alpha of the inclined pipe is not less than 15 degrees.

Compared with the prior art, the invention has the advantages of high pile forming reliability and pile foundation bearing capacity, effectively reducing soil disturbance, reducing particle crushing degree, improving pile side frictional resistance, better solving the problems of sand compaction and slow driving caused by a single vibration method, difficult pore forming in coral sand foundation and low side resistance, recycling the steel sleeve, greatly reducing engineering cost, being green and environment-friendly, and having good environmental protection benefit and popularization prospect.

Drawings

FIG. 1 is a schematic view of the alternating operation of vibration and static pressure of the present invention;

FIG. 2 is a schematic view of the placement of a reinforcement cage and a grouting sleeve;

FIG. 3 is a top view of FIG. 2;

FIG. 4 is a schematic illustration of sidewall grouting according to the present invention.

Detailed Description

The invention will be described and illustrated in further detail below with reference to a pile foundation engineering embodiment: