水库大坝地基地震液化特性及动力有限元分析

Liquefaction properties and dynamic FEM analysis of the dam foundation of reservoir under seismic load

为了考虑尔王庄水库大坝地基地震液化及动力特性,首先通过室内动三轴试验研究粉土、粉砂在动荷载作用下的孔压累积特性,提出了选择双幅应变达到5%作为土样液化的标准;然后采用现场标贯试验和室内动三轴试验对水库坝基中的粉土、粉砂层进行了液化判别,并对判别结果进行了对比分析;同时在液化判别的基础上利用有效应力动力分析方法对坝基土体进行了考虑渗流和不考虑渗流的地震液化的非线性动力有限元分析,并将液化的判别结果与现场标贯试验、室内动三轴试验的判别结果进行对比,从中得出一些有益的结论可供类似工程参考。

In order to analyze the liquefaction and dynamic properties of the reservoir dam foundation under seismic load, the silt and silty sand pore pressure accumulation properties are firstly obtained by indoor dynamic triaxial tests, the liquefaction criterion of whether the cyclic shear strain reaches 5% is also established. Then, the liquefaction evaluation of silt and silty sand is made according to the results of the standard penetration tests in-situs （SPT） and indoor dynamic triaxial tests; the results of them are then also compared. At the same time, on the basis of liquefaction evaluation, the non-linear dynamic FEM analysis by using effective stress method is performed. The effect of whether taking account of seepage effect is studied with the zone of the liquefaction. The results of the dynamic FEM analysis, indoor tests and SPT are compared. Some useful conclusions may be provided for references.