黄土动力特性试验及深厚黄土地基上土石坝抗震分析研究

Test of dynamic properties of loess and Study on resistance of earthquake impact for earth-rock dam on deep loess foundation

对某深厚黄土地基上土石坝的坝基黄土和筑坝黄土进行动三轴和共振柱等动力试验,求得其动强度、动应力-应变关系,以及用于计算动孔压的动孔压特性曲线及其他动参数。在静力分析的基础上对大坝连同地基进行了三维有效应力动力分析。计算表明,Ⅶ度地震下黄土坝基会出现液化,危及大坝安全。为此,建议了距上下游坝脚一定范围内对坝基进行填土压重的经济便利的大坝抗震措施,并对填土压重的抗液化效果进行了优化分析,最终得到经济合理的填土压重范围和压重厚度。

The dynamic triaxial test, resonance column test and other dynamic tests are carried out for the loesses which exist on subgrade and core wall of an earth-rock dam on deep loess foundation. The dynamic shear strength, dynamic stress-strain relation, dynamic pore water pressure curves and other dynamic parameters are obtained. Based on the dynamic test results and static analysis, the dynamic response analysis of the dam with foundation is calculated by 3D nonlinear effective stress FEM. The calculation results show that the loess foundation will be liquefied under the earthquake intensity Ⅶ. Therefore, an economical measure for overcoming the liquefying disaster is proposed. The effect of the resisting measure for earthquake destroying is discussed; and the optimum result is obtained at last.