压实条件及细粒含量对回填土抗震稳定性的影响

为了深入研究压实条件与细粒含量对土抗震稳定性的综合影响,对不同级配的土开展了循环荷载三轴试验,探讨了含水率、干密度、饱和度对其不排水动强度的影响规律及机理,分析了不同细粒含量压实土所呈现的动强度特征差异,并引入以压实度和饱和度为自变量的方程来定量表述动强度。研究结果表明:在一定的压实能量下,达到最大干密度的土并不一定具有最大的不排水动强度,对于细粒含量较大的土,动强度由压实度和饱和度同时决定,而对于细粒含量较小的土,动强度基本只受压实度的影响;利用动强度预测方程可以在不掌握击实曲线的前提下预测压实土的不排水动强度,为抗震稳定性评价提供依据。

Influence of compaction conditions and fines content on seismic stability of compacted backfill soils

To further study comprehensive effect of compaction conditions and fines content on soil seismic stability characteristics,a series of cyclic loading tri-axial tests were carried out on soils with different gradations.The influence rules and corresponding mechanism of moisture content,dry density and saturation on undrained dynamic strength were discussed.The discrepancy of dynamic strength characteristics caused by fines content difference was analyzed.And a equation with compaction degree and saturation degree as independent variables was introduced to quantitative express dynamic strength.The results show that under a certain compaction energy,soil with the highest dry density does not necessarily have the greatest undrained dynamic strength.For the soil with high fines content,dynamic strength is determined by both compaction degree and saturation,while for the soil with low fines content,dynamic strength is only affected by compaction degree.The undrained dynamic strength of compacted soil can be estimated by equation without knowing compaction curve.This method is useful for seismic stability evaluation.