Construction method of supporting bolts for deep foundation pit under high pressure

Abstract

The invention relates to a construction method of a high-pressure-bearing water-depth foundation pit supporting anchor rod. The construction method includes the steps of binding and fastening a reserved steel pipe of an underground diaphragm wall reinforcement cage, conducting pipe-following drilling through a steel sleeve, mounting a PVC sleeve and an anchor cable, conducting primary grouting, sealing and plugging pores, forming an anchored-section high-pressure grouting body through secondary high-pressure splitting grouting, conducting antiseptic treatment, tensioning and locking the anchor cable, conducting secondary grouting and leakage plugging on the pores and the like. By the adoption of the technology, the high-pressure-bearing water-depth foundation pit supporting anchor rod is constructed, the pore forming stability in the high-pressure-bearing water sandy cobble stratum and the reliability of anchored-section anchoring force are guaranteed, the excellent pore leakage plugging impermeability is achieved, construction efficiency is high, and the construction method of the high-pressure-bearing water-depth foundation pit supporting anchor rod has the remarkable technical economic benefits.

Description

technical field [0001] The invention belongs to the field of underground engineering, and in particular relates to a high-pressure-water-deep foundation pit support bolt construction method suitable for bolt construction in the presence of high-pressure water or difficulty in forming holes in the stratum. Background technique [0002] In the foundation pit support project, the support structure type of underground diaphragm wall or bored pile combined with prestressed anchor is often used. The prestressed anchor has higher requirements on the stratum. The hole wall is easy to collapse, especially when there is high pressure water in the gravel soil layer, as the water continues to gushes out, a large number of particles in the soil layer will be lost, resulting in excessive settlement and deformation behind the hole, affecting the safety of surrounding buildings and facilities . [0003] The following problems need to be solved in the construction of bolts in highly confine...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a construction method for supporting anchor rods in deep foundation pits with high pressure water for the problems of difficult hole formation, easy loss of soil, difficulty in guaranteeing grouting body, and leak plugging in high pressure water sand and pebble formations. This method adopts steel casing to drill with the pipe, built-in PVC casing, installs the anchor cable and grouts once, and the second high-pressure splitting grouting forms the high-pressure grouting body of the anchorage section, the hole expansion wooden plug and the quick-setting quick-hardening material Plugging, combined with orifice grouting for plugging

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