细粒含量对砂土液化势影响探讨  

Discussion on the effects of fines content on liquefaction potential of sandy soils

作　　者：李方圆 董林 夏坤 李燕[1] 王晓磊[1] LI Fangyuan;DONG Lin;XIA Kun;LI Yan;WANG Xiaolei(College of Civil Engineering,Hebei University of Engineering,Handan 056038,China)

机构地区：[1]河北工程大学土木工程学院,河北邯郸056038

出　　处：《地震工程与工程振动》2022年第2期244-251,共8页Earthquake Engineering and Engineering Dynamics

基　　金：国家自然科学基金项目(51708525,51608496)。

摘　　要：细粒含量对砂土液化势的影响研究一直充斥着矛盾与争议,大量室内试验成果对现场粉砂、粉土液化判别方法的改进没有实质意义。文中分析了经典文献,从砂土与粉粒混合物最大、最小孔隙比试验数据入手,发现大部分砂土随细粒含量增大,最大、最小孔隙比都呈先减小、后增大的抛物线型,保持等孔隙比,试样相对密度先减小、后增大,动三轴试验抗液化强度随细粒含量变化趋势与上述相对密度变化趋势一致;对于孔隙比曲线下降段,大部分砂土随细粒含量增大,最小孔隙比下降快,说明细粒主要进入砂粒所组成的孔隙中,最大孔隙比下降慢,细粒主要赋存于砂粒接触点或接触面之间,由于液化问题一般都针对较松散土体,所以等骨架孔隙比意义不大;不同砂土配细粒,最大、最小孔隙比曲线所包括的范围差异很大,即使对同一砂土最大、最小孔隙比曲线,不同的等相对密度线,得出抗液化强度与细粒含量的关系都有区别。因此,最大、最小孔隙比曲线之间的范围(尤其是上半部分),必须得到全面的考虑。There has been significant controversy and confusion regarding the effects of fines content on liquefac⁃tion resistance of sands,and a large number of laboratory test results have little significance for improvement of liq⁃uefaction discrimination methods.In this paper,numerous studies reported in literature are analyzed.From the variation in index void ratios for mixtures of sand and silt,it is found that the maximum and the minimum void ratio decreases first and then increases as silt content increases for most of sands.If soil specimens are prepared to a con⁃stant void ratio at various silt contents,they will represent different relative densities,and this variation of relative density mirrors the decrease and then increase in cyclic resistance with increasing fine content.Besides,the concept of constant skeleton void ratio is problematic,especially for loose soils liquefaction,because more fine particles are found between surfaces of adjacent sand particles in loose sands than that in dense sands,macroscopic performance is the larger drops in the minimum void ratio than that in the maximum void ratio with initial increasing fine content.There are significant differences for range between the maximum and the minimum void ratio curves of different sands,even for one sand,relationship between liquefaction resistance and fine content will be different for different constant relative density.Therefore,the range between the maximum and the minimum void ratio curves(especially the upper half)must be considered comprehensively.

关 键 词：细粒含量 液化 孔隙比 骨架孔隙比 相对密度 

分 类 号：P315.9[天文地球—地震学] TU43[天文地球—固体地球物理学]