强震区碎石桩复合地基抗液化效果评价方法

Evaluation method of anti-liquefaction effect of stone column composite foundation in strong earthquake areas

碎石桩法作为常用的抗液化地基处理技术,目前国内现行规范在碎石桩设计及检测验收阶段均只考虑碎石桩对桩间土密实作用,而忽略其排水及减震抗液化作用。强震区地基抗液化要求高,采用碎石桩处理若仅考虑对桩间土密实作用,将导致碎石桩面积置换率较高,造成工程的浪费。针对国内外缺乏碎石桩复合地基综合抗液化效果检测与评价方法现状,基于碎石桩复合地基密实、排水、减震三大抗液化作用计算公式,提炼了碎石桩复合地基抗液化效果评估核心要素,提出三大抗液化作用的评价方法。结合工程实例,提出了强震区碎石桩复合地基抗液化效果检测验收流程及综合评价方法,可为碎石桩加固类似地基的抗液化效果检测与评价提供参考。

The stone column method is a widely used anti-liquefaction foundation treatment technology.Currently,existing Chinese specifications mainly consider the effect of stone columns on the densification of soil between columns in the design and testing and acceptance phases of the stone column,while ignoring the drainage effect and shear stress redistribution effects on anti-liquefaction.In the strong earthquake area,the requirement for an anti-liquefaction foundation is high.If the stone column treatment only considers the effect of densification of soil between columns,it will lead to a high replacement rate of stone columns and cause engineering waste.In view of the lack of testing and evaluation methods for the comprehensive anti-liquefaction effect of stone column composite foundation in China and abroad,this paper refines the core elements of the evaluation for the anti-liquefaction effect of stone column composite foundation and proposes the evaluation methods for each of the three major anti-liquefaction effects based on the calculation formulae for the three major anti-liquefaction effects of stone column composite foundation,namely densification,drainage,and shear stress redistribution.Combining with engineering examples,the paper also puts forward the process of testing and acceptance of the anti-liquefaction effect of stone column composite foundation in strong earthquake areas and the comprehensive evaluation method,which can provide a reference for the testing and evaluation of the anti-liquefaction effect of similar foundation reinforced by stone columns.