上海软土的动三轴试验和非线性损伤模型

用损伤观点研究上海淤泥质软土在动力荷载下的应力和应变的变化规律。试验结果说明,振次对土的性质影响很大,随着振次的增加,土体损伤不断增加,动应变增大,动应力却不断地减小。围压越大或者循环动应力比越大动强度越高,动应变发展的越快,越容易达到破坏。频率越大,土的破坏速度越快。三角形波比正弦波更易引起土的破坏。在试验基础上,定义了考虑振次影响的损伤变量,建立非线性损伤模型,并确定模型参数。

Dynamic Triaxial Tests of Shanghai Soft Soil and Non-linear Model

Dynamic triaxial tests are carried out and relationships between stress and strain are studied subjected to dynamic triaxial loading.It is shown that number of cycles has a strong influence on the characteristics of soil.With the increase in the number of cycles,damage develops quickly,dynamic strain increases and dynamic stress decreases.The larger confining pressure and cyclic stress ratio become,the quicker strain increases,the easier soil fails,but the higher strength is.The larger frequency is,the quicker soil fails.Soil fails easier subjected to triangular wave loading than that of sine wave.Based on the test data,the damage variable considering number of cycles is defined,the nonlinear damage model is established and the parameters are determined.