Complex karst site anti-collapse impact holing construction method

Abstract

The invention relates to a complex karst site anti-collapse impact holing construction method. The method comprises the following steps that a, a punching drilling machine is mounted, and a slurry pool and a slurry circulation system are prepared; b, a steel casing is driven and reinforced; c, impact holing is conducted through a punch hammer of the punching drilling machine in a short-stroke lowpunching and rapid tamping mode, and wall protection is conducted through the steel casing, a mudstone hole wall and the slurry circulation system; and d, a punched hole is cleaned, a reinforcement cage is descended, and concrete is poured. Through the anti-collapse impact holing construction method, construction is convenient and safe, construction in karst sites with complex geologies can be achieved, and meanwhile, the safety of pile driving machines and operators and the pile-forming quality of pile foundations are ensured.

Description

technical field [0001] The invention relates to a construction method for punching piles, in particular to a construction method for preventing collapse and impacting holes in complex karst sites. Background technique [0002] At present, the design method and construction technology of pile foundations are relatively mature, but the geological conditions in covered karst areas are complex, and the construction of pile foundations is prone to engineering quality problems such as "sliding piles", "hanging piles" and "semi-hanging piles". base instability. Therefore, before the construction of punching piles in karst sites, the soil caves and karst caves are generally grouted and the upper loose and weak soil layers are reinforced. According to the sequence of cave first big and then small, first outside and then inside, first concrete and then grout, first down and then up, use high-pressure pouring of plain concrete or cement mortar, low-pressure injection of pure cement gr...

AI Technical Summary

Problems solved by technology

This kind of karst grouting reinforcement method is relatively mature, but for unfilled, semi-filled or beaded connected karst caves, the amount of grouting is closely related to the grouting experience. Large, the cost is too high for pile foundation engineering, and the best economic benefits cannot be achieved; for the treatment method of strengthening the upper loose and weak soil layer, stirring piles are usually used for reinforcement; for strata with deep silt layers and sand layers, it is necessary Large-scale equipment is used and the reinforcement effect is not obvious; once the wall protection mud leaks when the pile foundation is formed, the hole collapse risk will easily occur, the project cost will increase, the construction time will be prolonged, and the use will be limited.

[0003] To sum up, in the pile foundation engineering of karst sites, grouting is used to fill dissolved soil caves or to strengthen soft soil layers in a large area. The huge amount of engineering, long construction period, and poor economic benefits limit its large-scale promotion. Therefore, there is an urgent need for a A construction method for preventing collapse and impacting holes in complex karst sites

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