不规则循环剪切荷载作用下土的粘弹塑性模型

场地地震反应问题最初是按等价线性粘弹性模型来考虑土的非线性特点的。近年来,迅速发展起真正非线性的方法。本文提出的土的非线性模型可以同时符合均匀循环荷载下的剪切模量与剪应变、阻尼比与剪应变曲线,并且可以计入粘滞阻尼的影响。为了适应不规则的剪应力循环荷载,提出了加卸载的准则及孔隙水压力生长的分数循环估算法。本文建议的模型已用于总应力法的场地地震反应计算机程序中。

Visco-Elastoplastic Soil Model for Irregular Shear Cyclic Dynamic Loadings

The visco-elastoplatic soil model, introduced in this paper, is consistent with the experimental relationships, such as shear modulus vs shear strain, damping ratio vs shear strain, pore pressure ratio vs cycle ratio and stress ratio vs number of liquefaction cycles, etc. The loading-reloading rules control the hysteresis loops beneath skeleton curve. The &;quot;apparent applied forces&;quot;method is suggested to evaluate the effects of soil viscosity. The generations of pore pressure are evaluated by&;quot;fraction cycle method&;quot;, which is simple and effective, especially for waved increases of pore water pressure.The soil model have been applied to a computer program （SRHSL-1978） for the total stress analysis of seismic response of site soil.