CN103195052A - Cast-in-place pile used in high concentration saline solution corrosion environment and construction method thereof - Google Patents

Abstract

The invention discloses a cast-in-place pile used in a high concentration saline solution corrosion environment and a construction method thereof. A steel pile casing is arranged on the periphery of a cast-in-place pile body, the bottom edge of the steel pile casing is arranged below a high concentration saline solution corrosion area, and the top edge of the steel pile casting is level to the top portion of the cast-in-place pile body. The construction method of the cast-in-place pile is that the length and wall thickness of the steel pile casing are determined first, the steel pile casing is manufactured in advance, then the steel pile casing is sunk to be in place and level to the designed height of the cast-in-place pile body, and finally the cast-in-place pile body is constructed in the steel pile casing. The steel pile casing is used as a corrosion-resistant protecting barrier of the cast-in-place pile body, and the high concentration saline solution is prevented from corroding the cast-in-place pile body. Corrosion-resistant age limit of the steel pile casing can be controlled through steel plate thickness, corrosion-resistant effect reliability degree is high, and a permanent protective effect within the service life of the cast-in-place pile body can be achieved. Construction is simple, the process is mature, the steel pile casing is used as a template of the cast-in-place pile in a construction process, a hole-collapsing preventing effect and a protecting effect for soil with loose surface layers and sludge soil are obtained, and the cast-in-place pile and the construction method are favorable for pile foundation construction.

Description

A cast-in-situ pile used in a high-concentration salt solution corrosion environment and its construction method

technical field

The invention relates to a pile foundation structure and a construction method thereof, in particular to an anti-corrosion structure of a cast-in-place pile foundation and a construction method thereof. the

Background technique

"Technical Specifications for Anti-corrosion of Concrete Structures in Highway Engineering (JTG/T B07-01-2006)" clearly stipulates that "the anti-corrosion durability of highway concrete structures shall be Design. When different components in the same structure and different parts of the same component have different local environments, they should be treated differently. The durability design of concrete structure anti-corrosion should ensure the application of the structure in its long-term service life In order to meet the needs of reliability, repairability and safety, maintenance and inspection requirements during use must be put forward." At the same time, the "General Specifications for Design of Highway Bridges and Culverts" proposes that the basic design principles of bridges are "advanced technology, safe and reliable, applicable and durable, and economical and reasonable. ", so the durable and anti-corrosion design of highway bridge components is an indispensable design link. the

According to the different design reference periods, service environment categories and environmental action levels of bridge components, the specification puts forward specific requirements for the corrosion resistance durability design of bridge components. Class F) components, additional anti-corrosion measures may be taken for durability design. the

The cast-in-situ pile foundation is located below the surface, which is a concealed project. It is not easy to be found after being damaged by corrosion, and the inspection and maintenance work is extremely difficult. Therefore, it poses a challenge to the anti-corrosion durability design of the cast-in-place pile foundation in a high-concentration salt solution corrosion environment. . The corrosion level of the cast-in-situ pile foundation under the corrosive environment of high-concentration salt solution is relatively high, generally above D level. In addition to meeting the basic structural requirements and material durability requirements of the code, necessary additional anti-corrosion measures must be taken to reduce the workload of post-maintenance, improve the durability of the pile foundation, and ensure the safety of the pile foundation components. the

Conventional anti-corrosion measures for cast-in-situ pile foundations are to put forward durability design requirements for concrete materials, and meet the design requirements by putting forward durability design indicators for concrete strength grade, maximum water-cement ratio, minimum amount of cementitious materials and concrete admixtures. According to the requirements of "Technical Specification for Corrosion Protection of Concrete Structures in Highway Engineering JTG/T B07-01-2006", for structural parts in important projects that are severely affected by the environment (D, E and F grades), the durability of the material meets the design requirements. On the other hand, it is necessary to take other necessary measures to ensure the safety and reliability of the main structure. the

Contents of the invention

The present invention aims to solve the technical problem of high anti-corrosion and durability requirements for cast-in-situ pile foundations used in high-concentration salt solution corrosion environments, and provides a cast-in-place pile and its construction method, which can improve the durability of the cast-in-situ pile foundation structure, At the same time, it reduces the difficulty of construction and the difficulty of later maintenance. the

In order to solve the problems of the technologies described above, the present invention is realized through the following technical solutions:

A cast-in-situ pile in a high-concentration salt solution corrosion environment, comprising a cast-in-situ pile body, a steel casing is arranged on the periphery of the cast-in-place pile body, the bottom edge of the steel casing is located below the high-concentration salt solution corrosion area, and the top edge is in contact with the cast-in-situ pile. The top of the cast-in-situ pile body is flush. the

Generally, the wall thickness of the steel casing is 12mm-25mm. the

Preferably, the wall thickness of the steel casing is 15mm-20mm. the

A construction method for cast-in-situ piles used in a high-concentration salt solution corrosion environment is carried out according to the following steps:

(1) Determine the length of the steel casing according to the corrosion range of the cast-in-place pile body, determine the wall thickness of the steel casing according to the design anti-corrosion period of the cast-in-situ pile body, and prefabricate the steel casing;

(2) Sink the steel casing into place according to the positioning of the pile foundation, sink until the top edge of the steel casing is flush with the design elevation of the cast-in-place pile body, and temporarily support the steel casing;

(3) Constructing the cast-in-place pile body in the steel casing. the

The beneficial effects of the present invention are:

The invention uses the steel casing as the anti-corrosion protection barrier of the cast-in-place pile body, which can isolate the high-concentration salt solution around the cast-in-situ pile body and prevent the high-concentration salt solution from corroding the cast-in-situ pile body; and the anti-corrosion life of the steel casing can be passed through the thickness of its steel plate Control, the anti-corrosion effect is highly reliable, and can achieve the effect of permanent protection within the service life of the cast-in-place pile body. the

The invention has simple construction and mature technology. During the construction process, the steel casing is used as the formwork of the cast-in-situ pile, which can protect the loose ground layer and muddy soil from collapsing holes, and is more conducive to pile foundation construction. the

Description of drawings

Fig. 1 is the structural representation of cast-in-place pile provided by the present invention;

Fig. 2 is a sectional view of cast-in-place pile provided by the present invention;

Fig. 3 is a schematic diagram of the use state of the cast-in-situ pile provided by the present invention. the

In the figure: 1: cast-in-situ pile body; 2: steel casing; 3: cap; 4: pier column. the

Detailed ways

The present invention will be described in further detail below through specific examples. The following examples can enable those skilled in the art to understand the present invention more comprehensively, but do not limit the present invention in any way. the

As shown in Figures 1 and 2, this embodiment discloses a cast-in-situ pile in a high-concentration salt solution corrosion environment. A steel casing 2 is arranged around the cast-in-situ pile body 1, and the steel casing 2 serves as the cast-in-situ pile body 1 Additional anti-corrosion components. The steel casing 2 is a cylindrical structure made of steel, and its height extends from the corrosion area of the high-concentration salt solution to the top of the cast-in-situ pile body 1 outside the cast-in-situ pile body 1 . The wall thickness of the steel casing 2 is controlled by the design anticorrosion period, and the anticorrosion effect is highly reliable. Generally, the wall thickness of the steel casing 2 is 12mm-25mm. Preferably, the wall thickness of the steel casing is 15 mm to 20 mm, and the wall thickness within this range can better guarantee the corrosion resistance requirements of the cast-in-situ piles within the design reference period of the bridge. the

As shown in Figure 3, cast-in-place pile of the present invention can be applied to bridge substructure, and bridge substructure comprises cap 3 and pier column 4, and the outside of cast-in-place pile body 1 of cap 3 bottom is provided with steel casing 2, steel casing 2. The bottom edge is located below the high-concentration salt solution corrosion area, and the top edge is flush with the top of the cast-in-situ pile 1 body. The steel casing 2 can isolate the high-concentration salt solution around the cast-in-situ pile body 1 and prevent the high-concentration salt solution from corroding the cast-in-situ pile body 1 . the

The construction method of the above-mentioned cast-in-place piles for high-concentration salt solution corrosion environment is as follows:

The cast-in-situ pile body 1 is subjected to stress analysis and cross-section reinforcement according to the conventional pile foundation. At the same time, the concrete of the cast-in-situ pile is made of high-performance durable concrete, and the thickness of the steel bar protection layer is determined according to the requirements of the anti-corrosion design code. The steel casing 2 does not participate in the structural force;

Determine the corrosion range of the cast-in-situ pile body 1 according to the geological report, determine the length of the steel casing 2 according to the corrosion range of the cast-in-place pile body 1; determine the wall thickness of the steel casing 2 according to the structural design reference period of the pile foundation;

Prefabricated steel casing 2 according to the length and wall thickness of steel casing 2;

Pile foundation positioning, according to the pile foundation positioning, sink the steel casing 2 into place until the top edge of the steel casing 2 is flush with the design elevation of the cast-in-situ pile body 1;

After the steel casing 2 is in place, the construction temporary support structure is buried;

After the drilling rig is in place, the construction of the cast-in-situ pile body 1 is carried out according to the conventional method. the

Although the preferred embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments. The above-mentioned specific embodiments are only illustrative and not restrictive. Those of ordinary skill in the art Under the enlightenment of the present invention, without departing from the purpose of the present invention and the scope of protection of the claims, personnel can also make specific changes in many forms, and these all belong to the protection scope of the present invention. the

Claims (4)

1. A cast-in-place pile for a high-concentration salt solution corrosion environment, comprising a cast-in-place pile body, characterized in that a steel casing is arranged on the periphery of the cast-in-place pile body, and the bottom edge of the steel casing is located at a place where the high-concentration salt solution corrodes Below the region, the top edge is flush with the top of the cast-in-place pile body. 2. A cast-in-situ pile for high-concentration saline solution corrosion environment according to claim 1, characterized in that the wall thickness of the steel casing is 12 mm to 25 mm. 3. A cast-in-situ pile for high-concentration saline solution corrosion environment according to claim 2, characterized in that the wall thickness of the steel casing is 15mm-20mm. 4. A cast-in-place pile construction method for high-concentration saline solution corrosion environment as claimed in claim 1, is characterized in that, carries out according to the following steps: (1) Determine the length of the steel casing according to the corrosion range of the cast-in-situ pile body, determine the wall thickness of the steel casing according to the design anticorrosion period of the cast-in-situ pile body, and prefabricate the steel casing; (2) Sink the steel casing into place according to the positioning of the pile foundation, sink until the top edge of the steel casing is flush with the design elevation of the cast-in-place pile body, and temporarily support the steel casing; (3) Constructing the cast-in-place pile body in the steel casing.

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