Construction method of bored pile main body steel casing under deepwater foundation and bare rock environment

Abstract

The invention discloses a construction method of a bored pile main body steel casing under a deepwater foundation and bare rock environment, which comprises the following steps of: when a large-diameter bored pile in a deepwater sea area is constructed, firstly, leveling a seabed by adopting an auxiliary steel casing, then guiding a hole in a hole guiding channel of the auxiliary steel casing, emptying bare rock at the position of a casing wall, hoisting away the auxiliary steel casing, and finally, constructing the large-diameter bored pile in the deepwater sea area. And the main steel casing is placed in the hollowed-out hole, and finally, grouting and built-in are conducted inside and outside the main steel casing of the circular ring hole, so that a built-in layer is formed in the section, and the main steel casing becomes a stable structure. According to the construction method for sinking the bored pile main body steel casing through the auxiliary steel casing, the requirement for the plane precision of a first lead hole is low, a self-stabilizing foundation of the main body steel casing under the bare rock and inclined rock surface environment is provided, and rapid rock entering of the auxiliary steel casing under the bare rock geology is greatly facilitated; the problem of built-in of the main body steel casing in the bare rock geological environment is solved, the risk of offshore construction is reduced, and good economic benefits are generated.

Description

technical field [0001] The invention relates to a construction method for a bridge engineering bored pile structure, in particular to a construction method for a steel casing of a bored pile main body under deep water foundations and bare rock environments. Background technique [0002] With the rapid development of my country's economy and society, the scale of infrastructure construction is also increasing, and bridge construction is constantly moving towards deep-water harbor areas and ocean areas. In general water environment, the traditional bored pile construction uses thin-walled round steel pipes as steel casings, which are lowered by floating cranes, and then drilled with drilling platforms on the water; however, for inclined rock formations with bare rock geology and relatively hard rock strength, use Conventional construction methods will cause the following problems: [0003] (1) After the simple steel casing is lowered, it cannot be self-stabilized, cannot resi...

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Problems solved by technology

[0003] (1) After the simple steel casing is lowered, it cannot be self-stabilized, cannot resist the wind and wave environment, and cannot carry out drilling construction;

[0004] (2) For deep-water foundations exceeding a certain depth, if the large-diameter steel casing adopts a simple steel pipe structure and the wall thickness of the casing is selected according to common specifications, the weight of the steel casing will be heavy, and the requirements for hoisting equipment will be too high. The above comparison is not the optimal solution; if the wall thickness of the steel casing is reduced, the rigidity of the steel casing is likely to be insufficient under deep water foundations

[0005] Therefore, the traditional bored pile construction method and the single steel pipe casing structure have certain limitations in the construction of deep water foundations, inclined seabeds, and bare rock geological environments; in similar cases, an auxiliary structure with high rigidity and light weight must be used The steel casing structure pre-treats the seabed for the lead hole. When the treated seabed has self-stabilization conditions, the main steel casing is lowered to carry out drilling construction

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