【摘要】 通过对石碑塬黄土进行室内动三轴液化试验,研究不同动荷载水平下不同层位黄土的动应变和孔隙水压力发展特征,分析海原地震中石碑塬黄土地震液化的机制,并根据黄土所具有的特殊性质,探讨饱和黄土液化的判别标准。结果表明:饱和黄土液化时孔隙水压力发展受动荷载、颗粒组成和塑性指数等多因素的影响,相对于动残余应变的发展具有滞后性,因此往往达不到有效围压;而动残余应变的发展特征主要受初始孔隙比的影响,且当其超过3%后急剧增大,因此可选取该应变作为饱和黄土液化破坏的判别标准。更多还原

【Abstract】 On the basis of the dynamic triaxial liquefaction test of the loess samples which were taken from the Shibei tableland, Guyuan city, the characteristics of dynamic strain and pore water pressure of loess which at different layers are studied under the different levels of dynamic loads,the mechanism of the loess liquefaction in Haiyuan earthquake is analyzed. Moreover,the liquefaction criterion of saturated loess is discussed according to the special properties of loess. The results show that the development of pore water pressure influenced by various factors which contains dynamic load,grain composition,plasticity indices when the saturated loess liquefaction. It has the nature of hysteretic relative to the development of dynamic residual strain,so it often can not reach the effective confining pressure. However,the characteristics of dynamic residual strain development mainly by the influence of the initial void ratio,and increasing sharply when it exceeded 3%. Therefore,the dynamic residual strain reach to 3% can be chosen as the critical value of the saturation loess liquefaction.更多还原