Micro-disturbance construction method for full-casing cast-in-situ bored pile adjacent to subway

Abstract

The invention provides a micro-disturbance construction method for a full-casing cast-in-situ bored pile adjacent to a subway, and belongs to the technical field of foundation engineering. The micro-disturbance construction method adopts a 360-degree full-rotation drilling machine to rotate a customized steel casing into soil firstly, so that the steel casing penetrates through (3)-4b silty clay powder mixed lump silty-fine sand layer and (3)-4c silty-fine sand layer to enter a supporting layer by 100 mm; then, a rotary drilling rig is adopted for taking soil in a cylinder, a reinforcement cage is lowered, concrete is poured, slight disturbance to an adjacent subway is achieved in the whole construction process, a customized steel sleeve with a plate tooth tool bit is used for drilling, through reasonable segmentation of the steel sleeve, optimization of the connection mode between segments and the like, the steel sleeve can smoothly penetrate through a silty-fine sand layer with the thickness of 17 m without deformation, and the hole forming quality is guaranteed; and due to the fact that a steel sleeve protecting wall is adopted in the hole forming process, the phenomena of sandflowing, sand gushing and hole collapsing in a hole are effectively prevented, the pile forming quality of concrete in the sleeve is improved, a soil body is basically free of deformation in the construction process, and the influence on the surrounding environment is effectively controlled.

Description

technical field [0001] The invention belongs to the technical field of foundation engineering, and in particular relates to a micro-disturbance construction method for a full-casing bored pile adjacent to a subway. Background technique [0002] With the intensification of the urban rail transit line network, there are more and more situations where the surrounding buildings are demolished and rebuilt during the operation of the subway, and there are more and more cases of crossing the subway tunnel on the railway and highway. common. [0003] The conventional construction process of bored piles with mud retaining wall is: drilling machine in place → drilling → mud injection → continue drilling → slag discharge → hole cleaning → lifting reinforcement cage → bottom cleaning → pouring concrete, this construction process During the hole forming process, due to the release of soil stress around the hole wall, the soil is more likely to move toward the center of the hole, and eve...

AI Technical Summary

Problems solved by technology

[0004] The embodiment of the present invention provides a micro-disturbance construction method for a full casing bored pile adjacent to a subway. Even if the hole wall collapses or shrinks in diameter, when the construction is near the existing subway tunnel, it will inevitably cause a large displacement and deformation of the subway tunnel, which will seriously affect the operation safety of the train and bring difficulties to the maintenance and repair of the subway in the later period

Images