Re-drilling concrete wall protecting method for hole formation of rock-socketed pile in karst region

Abstract

The invention relates to a re-drilling concrete wall protecting method for hole formation of a rock-socketed pile in a karst region. Firstly, a plain concrete bored pile comprising a retaining concrete thin-wall tubular pile and a concrete solid pile capable of being extracted from the plain concrete bored pile as the core of the plain concrete bored pile and located inside the retaining concrete thin-wall tubular pile is constructed in overlaying soil, the pile diameter of the plain concrete bored pile is larger than the hole diameter of a pile hole of a rock-socketed pile of underlying bedrock, the pile length of the plain concrete bored pile is the depth from the natural ground to the top surface of the underlying bedrock, after the age of concrete of a pile body reaches 3-7 d, the core (namely the concrete solid pile) of the plain concrete bored pile is extracted by a rotary drilling rig, after the concrete solid pile is taken out, a re-drilling concrete wall protecting structure is formed by the wall protecting concrete thin-wall tubular pile, then the underlying bedrock is exposed, and hole formation construction of the rock-socketed pile of the underlying bedrock is conducted in a bedrock stratum. The method has the advantages of simplicity, easiness in operation, stability, reliability, high hole formation efficiency, large wall protecting depth, wide application range, environment-friendliness and the like and can provide a reference for hole formation construction of rock-socketed piles in similar strata.

Description

Technical field [0001] The invention relates to a method for re-drilling concrete wall protection, which is especially suitable for the wall protection of the hole-forming construction of rock-socketed piles at the overlying soil layer in karst areas. Background technique [0002] With the rapid development of social economy, urban construction is also in full swing, and it is inevitable to carry out engineering construction in karst areas. Before the construction of the main structure of the building, the construction of the building foundation is the primary link. When the bearing capacity and deformation control requirements must be met at the same time, the design needs to choose rock-socketed piles as the main foundation form of the high-rise building. It is inevitable for the pile foundation to form holes in the bedrock. Because there are caves, crevices, karst grooves or karst grooves in the bedrock stratum, when the hole construction of rock-socketed piles exposes the u...

AI Technical Summary

Problems solved by technology

Before the construction of the main structure of the building, the construction of the building foundation is the first link. When the bearing capacity and deformation control requirements must be met at the same time, the design needs to choose rock-socketed piles as the main foundation form of high-rise buildings. At this time, the following It is inevitable to form holes in the pile foundation in the bedrock. Because there are caves, fissures, ditches or grooves in the bedrock strata, when the hole-forming construction of rock-socketed piles exposes the underlying bedrock, the caves, fissures, and ditches Or the dissolution tank and the interior of the pile hole will form a communication channel. Once the cave, dissolution gap, dissolution ditch or dissolution tank is not completely filled, water leakage and slurry leakage will occur instantly, resulting in negative pore pressure inside the pile hole, and the water level of the cement slurry will drop rapidly. The wall of the pile hole formed in the overlying soil layer will immediately collapse due to the loss of the wall protection effect of the cement slurry, which will lead to ground subsidence and the overturning of the drilling rig, which will directly endanger the safety of construction personnel and mechanical equipment. It is too late to prevent the hole wall from collapsing even if the cement slurry is added inside

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