阅读说明：本技术 适用于强腐蚀性地质条件下的后注浆灌注桩及其施工方法 (Post-grouting cast-in-place pile suitable for strongly corrosive geological conditions and construction method thereof ) 是由 李俊刚 邓尤贵 陈罡 王兆村 朱美佳 闫虹瑞 于 2021-09-26 设计创作，主要内容包括：适用于强腐蚀性地质条件下的后注浆灌注桩及其施工方法,涉及混凝土灌注桩设计及施工技术领域。本发明解决了强腐蚀性坚硬土地质条件下不宜采用混凝土灌注桩而预制桩沉桩困难的问题。本发明包括钢管护筒、灌注桩本体、后注浆层；具体实施主要包括定位放线、强腐蚀性介质深度范围内钻孔、吊放所述钢管护筒、更换钻头并进行二次钻孔、清孔后吊放钢筋笼、二次清孔、灌注桩身混凝土、钢管护筒外侧后注浆、工程桩检测等。本发明提供的钢管护筒+后注浆灌注桩设计及其施工方法可有效解决强腐蚀性坚硬土地质条件下灌注桩硬化前强腐蚀性介质对灌注桩的腐蚀问题,同时能保证灌注桩与桩周土之间的侧摩阻,施工简单,具有良好的市场前景。(A post-grouting bored concrete pile suitable for highly corrosive geological conditions and a construction method thereof relate to the technical field of concrete bored concrete pile design and construction. The invention solves the problem that the precast pile is difficult to sink because the concrete cast-in-place pile is not suitable for the hard soil texture condition with strong corrosivity. The invention comprises a steel pipe pile casing, a cast-in-place pile body and a rear grouting layer; the concrete implementation mainly comprises positioning and paying off, drilling in a depth range of strong corrosive medium, hoisting the steel pipe casing, replacing a drill bit, carrying out secondary drilling, hoisting a reinforcement cage after hole cleaning, cleaning holes secondarily, pouring pile body concrete, grouting outside the steel pipe casing, detecting engineering piles and the like. The design and construction method of the steel pipe casing and the post-grouting cast-in-place pile can effectively solve the problem that the cast-in-place pile is corroded by a strong corrosive medium before the cast-in-place pile is hardened under the condition of strong corrosive hard soil, can ensure the side friction between the cast-in-place pile and the soil around the pile, and has simple construction and good market prospect.)

1. Post slip casting bored concrete pile suitable for under strong corrosive nature geological conditions, its characterized in that: the post-grouting bored concrete pile comprises a bored concrete pile body (1), a steel pipe pile casing (2) and a post-grouting layer (6); wherein the steel pipe pile casing (2) is positioned at the outer side of the cast-in-place pile (1); the rear grouting layer (6) is positioned on the outer side of the steel pipe pile casing (2); the cast-in-place pile body (1), the steel pipe pile casing (2) and the rear grouting layer (6) penetrate through a strong-corrosion interface and enter a non-strong-corrosion medium (5).

2. The post-grouting bored concrete pile construction method suitable for the strongly corrosive geological condition is characterized by comprising the following steps of: drilling twice, wherein the first drilling is drilling in the depth range of a strong corrosive medium, and hoisting a steel pipe protective cylinder; the second drilling is the drilling within the depth range of the non-strong corrosive medium, and a reinforcement cage is hoisted to carry out the operation of pouring the cast-in-place pile body; and after the cast-in-place pile body is initially set, grouting is carried out on the outer side of the steel pipe pile casing to form a rear grouting layer.

Technical Field

The invention relates to a post-grouting bored concrete pile design and construction method suitable for a strong corrosive hard soil geological condition, and relates to the technical field of bored concrete pile design and construction.

Background

With the rapid advance of social and economic transformation and urban construction processes, a large number of old industrial parks are gradually left unused. In order to fully utilize the old industrial sites, the old industrial sites need to be reformed and utilized, the influence of the past industrial production on the surrounding environment is large, and part of sites have strong corrosivity on reinforced concrete structures. For the reconstructed building, when the foundation bears large pulling force, the pile foundation is an economic and reasonable foundation scheme.

When hard soil exists in a certain depth range around the pile body, pile sinking of the precast pile is very difficult. When adopting the bored concrete pile, because the bored concrete pile is in the cast-in-place construction, easy and the strong corrosive medium contact under the unhardened condition of concrete, the protection is comparatively difficult, and inside strong corrosive medium got into the bored concrete pile, the durability of concrete is difficult to be guaranteed, so need take special processing mode under the strong corrosive environment bored concrete pile. The invention aims to find a concrete cast-in-place pile form suitable for the geological condition of strong corrosive hard soil, and solve the problems of corrosion of a strong corrosive medium to pile body concrete and steel bars and effective side friction between a blocking material and pile surrounding soil in the cast-in-place pile casting hardening process.

Disclosure of Invention

The invention mainly solves the problem that the pile sinking of the precast pile is difficult because the cast-in-place concrete pile is not suitable under the condition of strong corrosive hard soil texture, and is mainly characterized in that a blocking material is arranged between the cast-in-place concrete pile and a strong corrosive medium, specifically, a steel pipe pile casing is arranged in the depth range related to the strong corrosive medium at first, then the cast-in-place pile is poured, the strong corrosive medium can be blocked from directly contacting with a pile body before the cast-in-place pile concrete is hardened through the steel pipe pile casing, in addition, a post-grouting pipe is arranged on the outer side of the steel pipe pile casing, and the side friction between the steel pipe pile casing and the pile surrounding soil is ensured through the grouting of the post-grouting pipe after the pile body concrete is initially set.

A post-grouting bored concrete pile suitable for strongly corrosive geological conditions comprises a bored concrete pile body 1, a steel pipe pile casing 2 and a post-grouting layer 6; wherein the steel pipe pile casing 2 is positioned outside the cast-in-place pile 1; the rear grouting layer 6 is positioned on the outer side of the steel pipe casing 2; the cast-in-place pile body 1, the steel pipe pile casing 2 and the rear grouting layer 6 penetrate through a strong corrosive interface and enter a non-strong corrosive medium 5.

A post-grouting bored concrete pile construction method suitable for under the strongly corrosive geological condition includes drilling twice, the first drilling is a drilling within the depth range of a strongly corrosive medium, and the steel pipe pile casing is hoisted; the second drilling is a drilling within the depth range of the non-strong corrosive medium, and a reinforcement cage is hoisted to perform the operation of the cast-in-place pile body; after the cast-in-place pile body is initially set, grouting after passing through the outer side rear grouting pipe; the method mainly comprises the following implementation steps:

step one, positioning and paying off: positioning the pile according to the known coordinate points and the general plane diagram;

step two, drilling in the depth range of the strong corrosive medium: the diameter of the drill hole is D3, and the drill hole penetrates through a strong corrosive interface to enter a non-strong corrosive medium;

step three, hoisting the steel pipe protection cylinder: a rear grouting pipe 3 is arranged on the outer side of the steel pipe casing 2, and is hoisted and placed into the drill hole;

step four, replacing the drill bit and carrying out secondary drilling: replacing a drill bit matched with the diameter of the cast-in-place pile body 1, performing secondary drilling, and drilling to the bottom of the pile;

fifthly, after the secondary drilling hole is cleaned, hoisting a reinforcement cage;

step six, secondary hole cleaning;

step seven, pouring concrete into the pile body: pouring high-performance concrete;

step eight, post grouting outside the steel pipe pile casing: after the cast-in-place pile body 1 is initially set, grouting is carried out through the outer side rear grouting pipe 3, and side friction between the steel pipe pile casing 2 and the soil around the pile is guaranteed;

step nine: detecting the engineering pile: and carrying out integrity detection and bearing capacity detection according to the specification requirement.

The design and the construction method of the post-grouting cast-in-place pile outside the steel pipe pile casing can solve the problem that the strong corrosive medium corrodes concrete and steel bars before cast-in-place pile concrete is hardened under the condition of strong corrosive hard soil, can ensure the side friction between the cast-in-place pile and the soil around the pile, and have simple construction and good market prospect.

Drawings

FIG. 1 is a schematic diagram of a post-grouting bored concrete pile suitable for a strong corrosive hard soil geological condition, according to the present invention;

wherein: the grouting pile comprises a cast-in-place pile 1, a steel pipe pile casing 2, a rear grouting pipe 3, a strong corrosive medium 4, a non-strong corrosive medium 5, a rear grouting layer 6 and the like.

Detailed Description

The utility model provides a back slip casting bored concrete pile suitable for under strong corrosive geological conditions, mainly relates to bored concrete pile 1, steel pipe pile casing 2, back slip casting pipe 3, strong corrosive medium 4, non-strong corrosive medium 5, back slip casting 6, and the embodiment mainly includes following step:

step one, positioning and paying off: positioning the pile according to the known coordinate points and the general plane diagram;

step two, drilling in the depth range of the strong corrosive medium: the diameter of the drill hole is D3, and the drill hole penetrates through a strong corrosive interface to enter a non-strong corrosive medium 6 for a certain length L3;

step three, hoisting the steel pipe casing 2: a rear grouting pipe 3 is arranged on the outer side of the steel pipe casing 2, and is hoisted and placed into the drill hole;

step four, replacing the drill bit and carrying out secondary drilling: replacing a drill bit matched with the diameter of the cast-in-place pile 1, carrying out secondary drilling, and drilling to the bottom of the pile, wherein the bottom of the pile enters a bearing stratum by a certain depth, and a pile body comprises two sections L1 and L2;

fifthly, hoisting a reinforcement cage after hole cleaning;

step six, secondary hole cleaning;

step seven, pouring concrete into the pile body: pouring high-performance concrete;

step eight, post grouting outside the steel pipe pile casing: after the pile body of the cast-in-place pile 1 is initially set, the outer side rear grouting pipe 3 is used for grouting, so that the side friction between the steel pipe pile casing 2 and the soil around the pile is ensured.

Step nine: detecting the engineering pile: and carrying out integrity detection and bearing capacity detection according to the specification requirement.