基于液化势指标的砂土抗液化评价方法及应用

EVALUATION METHOD AND APPLICATION OF SAND LIQUEFACTION RESISTANCE BASED ON LIQUEFACTION POTENTIAL INDEX

在散粒体最大最小孔隙比理论的基础上,采用一种新的液化势指标对不同颗粒级配的二元砂粉混合物进行抗液化能力预测。通过对已有文献数据中砂粉混合物的体积应变势进行计算,分析混合物的细粒含量、粒径比与循环抗力比CRR的关系,结合混合物所处实际孔隙比提出了一个新的液化势指标ε′v。与砂粉混合物的CRR试验数据对比分析显示:各类砂粉混合物的CRR均随ε′v的增大而单调地降低,且两者呈现良好的幂函数关系,并进一步建立了CRR-ε′v关系曲线最佳拟合参数与粒径比的关系。对蒙特利砂混合耶茨维尔粉土试样进行的CRR预测结果表明,ε′v综合反映了土粒径分布、密实状态和颗粒形状的综合影响,是表征砂粉混合物CRR的一个有效指标。实际工程中可代替传统的现场原位试验,仅通过简单的室内试验预测场地土层抗液化能力。

Based on the theory of maximum and minimum void ratios of granular materials,a new liquefaction potential index was used to predict the liquefaction resistance of binary sand silt mixtures with different particle gradations.By calculating the volume strain potential of sand silt mixtures in the existing literature data,the relationship among the fine particle content,the particle size ratio and the cyclic resistance ratio CRR of the mixture was analyzed.A new liquefaction potential indexε′v was proposed combined with the actual void ratio of the mixture.The comparative analysis with the CRR test data of sand silt mixtures shows that the CRR of all kinds of sand silt mixtures decreases monotonously with the increase ofε′v,and the two parameters show a good power function relationship.Further,the relationship was established for the best fitting parameters of CRR-ε′v relationship curve and particle size ratio.The CRR prediction results of Monterey sand mixed Yatesville silt samples show that theε′v comprehensively reflects the comprehensive effects of soil particle size distribution,compaction state and particle shape,and is an effective index to characterize the CRR of sand silt mixtures.In practical engineering,it can replace the traditional in-situ test and predict the anti-liquefaction capacity of site soil layer only through simple indoor test.