Precast pile combined pile structure for special soil foundation, design method and construction method of precast pile combined pile structure

Abstract

The invention discloses a precast pile combined pile structure for a special soil foundation, a design method and a construction method of the precast pile combined pile structure, and relates to the technical field of building foundations. According to the design method, different combination modes of large piles and small piles and related parameters are selected according to different soil foundation conditions; a precast pile obtained according to the design method structurally comprises at least two precast piles, the section of at least one precast pile is smaller than that of other precast piles, prestressed steel bars and spiral stirrups are arranged in the precast piles, at least one end of a prestressed steel bar body is provided with an upset cap, and a boss is arranged at the top of the upset cap; and finally, the obtained precast pile is used for construction, and the corresponding construction method is obtained. According to the precast pile combined pile structure for the special soil foundation, the design method and the construction method of the precast pile combined pile structure, the bearing capacity of building pile foundations for underground foundation floating resistance in liquefied soil, frost heaving soil and collapsible loess areas can be improved effectively.

Description

technical field [0001] The invention relates to the technical field of building foundations, in particular to a prefabricated pile composite pile foundation structure for special soil foundations, a design method and a construction method thereof. Background technique [0002] In areas of liquefied soil, frost heaving soil and collapsible loess and building pile foundations used for anti-floating of underground foundations have always affected the safety and use of buildings. Collapsible loess is widely distributed in my country, and collapsible loess accounts for more than 70% of the total area of ​​loess in the country. Before construction in collapsible loess areas, the collapsibility of the foundation must be treated, otherwise the foundation will be affected by groundwater. After erosion, it is very easy to cause a series of disasters such as liquefaction and earthquake subsidence, which seriously endanger the safety of buildings located on collapsible loess. [0003] A...

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Problems solved by technology

[0003] At present, the main methods for foundation treatment in collapsible loess and liquefied soil areas include dynamic compaction, compaction piles, pre-soaked water, pile foundation, etc. The foundation treatment methods such as dynamic compaction, compacted piles, and pre-soaked water not only have high construction requirements The process is complicated, so the safety and reliability of the foundation cannot be guaranteed, and the depth of treatment is limited and the cost of foundation treatment is also high; Soil makes the foundation design and construction more difficult, and at the same time, the cost will also be greatly increased, and the existing design method has the problem of insufficient safety factor

For the anti-floating foundation of the underground foundation and the building foundation located in the frost heaving soil area, when prefabricated piles are used, prefabricated piles with equal side length or equal diameter or prefabricated piles with various special-shaped cross-sections are often used, such as ribbed piles on the outside of the pile body. Prefabricated piles increase the friction between the surface and the soil, thereby improving the ability of the pile foundation to float due to rising groundwater levels and soil frost heave. However, this single pile structure requires modification of the existing mold and additional modification Cost and due to the complex structure of the pile body, there are problems of low manufacturing efficiency, inconvenient stacking and transportation

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