1. College of Transportation Science & Engineering, Nanjing Tech. University, Nanjing, Jiangsu 210009, China;
2. College of Architecture and Civil Engineering, Beijing University of Technology, Beijing 100124, China
摘要：
可用于液化分析的本构模型在土层地震反应分析时难以模拟液化后引起的饱和砂土大变形反应，且适用于饱和砂土场地地震反应分析的非线性时域大变形本构的研究也相对较少。现针对饱和砂土液化大变形条件下的动力反应分析缺少相应的时域大变形本构开展研究，以期通过试验分析和理论研究提出一种可行的、简单适用的时域大变形本构。基于不排水循环三轴试验数据分析得到的饱和砂土液化后大变形应力?应变行为的规律，提出适用于饱和砂土液化后大变形的加卸载准则。结合笔者提出的基于对数动骨架曲线的有效应力本构，得到能定量描述饱和砂土液化大变形途径的大变形本构。该本构依据实际试验结果，可以系统地模拟饱和砂土整个液化过程的变形规律。通过自行编制的土层地震反应分析程序Soilresp1D，实现了含可液化饱和砂土场地动力反应分析，结果表明，基于对数动骨架本构、有效应力修正对数动骨架本构及液化大变形本构提出的时域非线性大变形本构能直接应用于含饱和砂土场地的动力反应分析。
大变形本构
Abstract:
Most of the constitutive model for liquefaction analysis cannot simulate the large post-liquefaction deformation of saturated sand, and there is little research on the nonlinear time-domain large deformation constitutive relationships suitable for seismic response analysis of saturated sand sites. In this paper, a feasible, simple and applicable large deformation constitutive model for time domain analysis is proposed through experimental analysis and theoretical research. The post-liquefaction stress-strain relationships of liquefied sand are obtained based on the undrained cyclic triaxial test data, then loading-reloading rules of large post-liquefaction deformation are proposed. Combined with the effective stress constitutive model based on logarithmic skeleton curve, a constitutive model that can quantitatively describe the large deformation of saturated sand liquefaction is proposed. According to the test results, the constitutive model can simulate small to large deformations from the pre-to post-liquefaction regime of sand. This constitutive model is also implemented to the program Soilresp1D for the dynamic response analysis of liquefiable soil sites. The results show that the time domain nonlinear large deformation unified constitutive model based on the logarithmic dynamic skeleton curve, effective stress-modified logarithmic dynamic skeleton constitutive model and liquefaction large deformation constitutive model can be directly applied to the dynamic response analysis of saturated sand.
Key words:
logarithmic skeleton curve,
effective stress,
liquefaction of saturated sand,
loading-unloading rules,
large deformation constitutive model
地址：湖北武汉武昌小洪山中国科学院武汉岩土力学研究所(430071) 邮编：200042 电话：027-87198484, 87199252, 87199253, 87198752 E-mail: [email protected]
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