岩溶地区某广场钻孔灌注桩基础补强加固设计与新技术

A new technology of reinforcement by cast-in-place pile foundation in karst areas

为解决岩溶地基上高层建筑桩基缺陷问题,提出了一种采用低坍落度塑性砼对缺陷桩基础进行加固处理的可控压密注浆技术。此技术通过特制高压泵,将强度不低于20MPa、坍落度不大于50mm的低坍落度砼压入强岩溶发育地层,形成有效桩径,以改善桩基缺陷。通过现场试验与全面施工,开发出成套施工工艺,有效解决了灰岩地区桩基础持力层缺陷问题。

To solve the defect of pile foundation of high buildings on karst foundation,this paper proposes a controllable pressure-tight grouting technology that uses low slump plastic concrete to reinforce the defect pile foundation.This technology uses a special high-pressure pump to form an effective pile diameter to improve pile foundation defects,which presses low slump with a strength of no less than 20 MPa and a slump of no more than 50mm into the strong karst development stratum.By means of in-situ tests and full-scale construction,a complete set of construction technology has been developed,which can be effectively applied to the treatment of bearing layer defects of pile foundation in limestone areas.