碎石桩加固饱和粉土地基的抗液化特性

Characteristics of Liquefaction Resistance for Stone Columns Treated in Saturated Silt Ground

除饱和砂土液化外,饱和粉土地震液化问题也是岩土地震工程中一个重要的研究课题。饱和粉土地基的地震液化及变形可以采用多种地基加固方法防治,碎石桩技术是常用方法之一。碎石桩复合地基的抗液化效应,主要是增加桩周土体的密度、利于桩体的排水以及由桩体分担地震水平剪应力(桩体减震作用)。但由于粉土的土质特性,粉土-碎石桩复合地基的抗液化特性与砂土有着明显的差异。本文结合目前国内外碎石桩复合地基抗液化研究的最新进展,对粉土-碎石桩的密实、排水减压和减震作用做了较详细的评述,最后提出了关于碎石柱复合地基抗液化特性需要进一步研究的问题。

Liquefaction of saturated silt is still an important topic remaining in geotechnical earthquake engineering besides liquefaction of sands.The risk of liquefaction and associated ground deformation can be reduced by various ground-improvement methods including the stone column technique.The effectiveness of stone columns for the prevention of soil liquefaction during an earthquake is often threefold：densification, drainage and the reduction of the total cyclic shear stress in the soil.However,there are obvious difference of characteristics of stone columns liquefaction resistance between in saturated silts and in sands. In this paper,a detailed review on effectiveness of densification,drainage and reinforcement of stone columns for the resistance of soil liquefaction during earthquakes is presented.The suggestions are offered for some problems worthy of further study.