阅读说明：本技术 一种抗上拱变形钻孔灌注桩的施工方法 (Construction method of anti-arching deformation cast-in-situ bored pile ) 是由 姚裕春 李安洪 龚建辉 吴沛沛 李宁 张耀 高继涛 袁报 房立凤 于 2018-06-05 设计创作，主要内容包括：一种抗上拱变形钻孔灌注桩的施工方法,以有效消除钻孔灌注桩在上拱变形区的不利摩擦阻力影响,从而节约工程投资。包括如下步骤：在地基上进行钻孔灌注桩施工平面定位；钻孔灌注桩桩孔施工,采用泥浆进行护壁,直至施工设计高程；制作与钻孔灌注桩桩径匹配的外护管,长度等于地面至上拱变形区分界线的深度；在外护管的内壁上覆盖固定复合土工膜；把内衬复合土工膜的外护管压入钻孔灌注桩的桩孔内,管口与地面齐平；穿过外护管,在桩孔中放入钻孔灌注桩的钢筋笼；向桩孔底部置入混凝土注入管,从孔底注入混凝土,缓慢提升混凝土注入管,直至设计桩顶高程。(a construction method of an upward-arching deformation resistant cast-in-situ bored pile is used for effectively eliminating the adverse friction resistance influence of the cast-in-situ bored pile in an upward-arching deformation area, so that the engineering investment is saved. The method comprises the following steps: performing construction plane positioning of the cast-in-situ bored pile on the foundation; drilling and pouring pile holes, and performing wall protection by adopting slurry until the construction design elevation is reached; manufacturing an outer protecting pipe matched with the diameter of the bored pile, wherein the length of the outer protecting pipe is equal to the depth of the boundary line of the upper arch deformation of the ground; covering and fixing a composite geomembrane on the inner wall of the outer protective pipe; pressing the outer protecting pipe of the lining composite geomembrane into a pile hole of the cast-in-situ bored pile, wherein the pipe orifice is flush with the ground; penetrating through the outer protecting pipe, and placing a reinforcement cage of the cast-in-situ bored pile into the pile hole; and (3) placing a concrete injection pipe into the bottom of the pile hole, injecting concrete from the hole bottom, and slowly lifting the concrete injection pipe until the pile top elevation is designed.)

1. a construction method of an upward-arching deformation resistant cast-in-situ bored pile comprises the following steps:

Firstly, performing construction plane positioning on a bored pile (1) on a foundation;

secondly, constructing a pile hole of the cast-in-situ bored pile (1), and performing wall protection by adopting slurry until the construction design elevation is reached;

Thirdly, manufacturing an outer protecting pipe (2) matched with the diameter of the cast-in-situ bored pile (1), wherein the length of the outer protecting pipe is equal to the depth of the boundary line (A) between the ground and the upper arch deformation;

Fourthly, covering and fixing the composite geomembrane (3) on the inner wall of the outer protective pipe (2);

Pressing the outer protective pipe (2) of the lining composite geomembrane (3) into a pile hole of the cast-in-situ bored pile (1) to enable the pipe orifice to be flush with the ground;

Sixthly, a reinforcement cage of the cast-in-situ bored pile (1) is placed in the pile hole after penetrating through the outer protective pipe (2);

And seventhly, placing a concrete injection pipe into the bottom of the pile hole, injecting concrete from the hole bottom, and slowly lifting the concrete injection pipe until the pile top elevation is designed.

2. the method for constructing an uplift deformation-resistant cast-in-situ bored pile as claimed in claim 1, wherein: the longitudinal two ends of the composite geomembrane (3) extend out of the upper port and the lower port of the outer protecting pipe (2) and are reversely folded and bonded with the outer wall of the outer protecting pipe (2).

3. The method for constructing an uplift deformation-resistant cast-in-situ bored pile as claimed in claim 1, wherein: the outer protecting pipe (2) is made of a PVC pipe.

Technical Field

the invention relates to geotechnical engineering, in particular to a construction method of an upward-arching deformation resistant cast-in-situ bored pile.

background

when the ballastless track high-speed railway passes through the expansive rock-soil foundation, the deep-cut soft rock foundation and the seasonally frozen soil region in the form of cutting, the following technical problems can occur: the expansive rock-soil foundation can generate a large upward expansive force under the action of water; under the great unloading action of the deep-excavated soft rock, the rock body can generate upward creep deformation or rheological deformation, and the duration time is long; the rock soil body in the freezing depth influence range of the seasonal frozen soil area generates cyclic frost heaving deformation, in order to ensure the operation safety of a high-speed railway, an upward arching deformation resisting structure is needed to be arranged, the cast-in-situ bored pile is a commonly used uplift pile structure, but when the cast-in-situ bored pile is used for resisting upward arching deformation, because foundation rock soil exists in an arching deformation area, the friction resistance of the rock soil body to the pile in the influence area is upward, which is unfavorable force, only the friction resistance of a non-arching deformation area is favorable, the existing problems cannot be solved by the traditional cast-in-situ bored pile construction, and therefore, the construction method for the upward arching resistant cast-in-situ bored pile is provided, and has the characteristics of being capable of eliminating the adverse friction influence of the arching deformation area, convenient to construct, good in economy, environment-.

Disclosure of Invention

The invention aims to solve the technical problem of providing a construction method of an upward-arching deformation resistant cast-in-situ bored pile, so as to effectively eliminate the adverse friction resistance influence of the cast-in-situ bored pile in an upward-arching deformation area, thereby saving the engineering investment.

the technical scheme adopted by the invention for solving the technical problems is as follows:

the invention relates to a construction method of an upward arch deformation resistant cast-in-situ bored pile, which comprises the following steps:

firstly, performing construction plane positioning of a cast-in-situ bored pile on a foundation;

Secondly, drilling and pouring pile holes, and adopting slurry to protect walls until the construction design elevation;

Manufacturing an outer protecting pipe matched with the diameter of the bored pile, wherein the length of the outer protecting pipe is equal to the depth of the boundary line of the upper arch deformation;

Covering and fixing a composite geomembrane on the inner wall of the outer protective pipe;

Pressing the outer protecting pipe lined with the composite geomembrane into a pile hole of the cast-in-situ bored pile, wherein the pipe orifice is flush with the ground;

sixthly, a reinforcement cage of the cast-in-situ bored pile is placed in the pile hole after penetrating through the outer protective pipe;

And seventhly, placing a concrete injection pipe into the bottom of the pile hole, injecting concrete from the hole bottom, and slowly lifting the concrete injection pipe until the pile top elevation is designed.

the invention has the advantages that the outer protecting pipe and the composite geomembrane are arranged in the upper arch deformation area of the foundation soil, the composite geomembrane is arranged to a required elevation position through the outer protecting pipe, the outer protecting pipe is contacted with the foundation soil with larger friction force, the composite geomembrane is contacted with the cast-in-situ bored pile with larger friction force, the friction force between the outer protecting pipe and the composite soil membrance is very low, when the foundation soil is subjected to upper arch deformation, unfavorable upward pulling force can not be generated on the cast-in-situ bored pile, the adverse friction resistance influence of the cast-in-situ bored pile in the upper arch deformation area can be effectively eliminated, and the anchoring section of the cast-in-situ bored pile for resisting pulling can be greatly reduced, so that the engineering investment is greatly saved; has the characteristics of convenient construction, high efficiency, economy, environmental protection and the like.

Drawings

The specification includes the following two figures:

Fig. 1 is a schematic structural diagram of a construction method of an upward arch deformation resistant cast-in-situ bored pile according to the present invention.

fig. 2 is a schematic structural view of an outer protecting pipe and a composite geomembrane of the construction method of the upward arching deformation resistant cast-in-situ bored pile of the present invention.

the component names and corresponding labels are shown in the figure: the cast-in-situ bored pile comprises a cast-in-situ bored pile 1, an outer protective pipe 2, a composite geomembrane 3 and an upper arch deformation influence distinguishing boundary A.

Detailed Description

The invention is further described with reference to the following figures and examples:

referring to fig. 1 and 2, the construction method of the cast-in-situ bored pile with the deformation resistance to the upward arch according to the present invention includes the following steps:

firstly, performing construction plane positioning on a cast-in-situ bored pile 1 on a foundation;

secondly, constructing a pile hole of the cast-in-situ bored pile 1, and performing wall protection by adopting slurry until the construction design elevation is reached;

Thirdly, manufacturing an outer protecting pipe 2 matched with the diameter of the cast-in-situ bored pile 1, wherein the length of the outer protecting pipe is equal to the depth of an arch deformation distinguishing boundary A from the ground;

fourthly, covering and fixing the composite geomembrane 3 on the inner wall of the outer protective pipe 2;

pressing the outer protective pipe 2 of the lining composite geomembrane 3 into the pile hole of the cast-in-situ bored pile 1, wherein the pipe orifice is flush with the ground;

sixthly, the steel reinforcement cage of the cast-in-situ bored pile 1 is placed in the pile hole after penetrating through the outer protective pipe 2;

and seventhly, placing a concrete injection pipe into the bottom of the pile hole, injecting concrete from the hole bottom, and slowly lifting the concrete injection pipe until the pile top elevation is designed.

through set up outer pillar 2 and compound geomembrane 3 in the deformation zone of encircleing on ground, bored concrete pile 1 is owing to set up compound geomembrane 3 in this degree of depth scope district, the frictional resistance of compound geomembrane 3 and outer pillar 2 is minimum, when the deformation takes place to encircleing for ground rock, can not produce unfavorable upwards pulling force to bored concrete pile 1, owing to avoided unfavorable arch force to bored concrete pile 1's effect, bored concrete pile 1 is used for the anchor section of resistance to plucking to reduce greatly, thereby practice thrift the engineering investment by a wide margin, and have construction convenience, high efficiency, economy, characteristics such as environmental protection.

The longitudinal two ends of the composite geomembrane 3 extend out of the upper port and the lower port of the outer protecting pipe 2, and are reversely folded and wrapped to be bonded with the outer wall of the outer protecting pipe 2. The length of the reverse turn-back pack is typically 1 m. The outer protective pipe 2 is usually made of PVC pipe.