循环荷载下砂土变形的细观数值模拟Ⅱ:密砂试验结果

Micro-numerical simulation of cyclic biaxial testⅡ: results of dense sand

采用颗粒流理论模拟了不同排水条件下密砂的双轴试验,通过开发的细观组构统计程序记录加载不同时刻试样的细观组构演化,研究了循环荷载作用下密砂变形过程中细观配位数、接触方向、粒间接触力等的演化规律及其与试样宏观力学响应之间的内在联系。探讨了密砂在循环荷载作用下诱发各向异性、剪胀软化、循环活动性等产生的微细观机理。与松砂相比,密砂在循环荷载作用下,组构各向异性与应力各向异性彼此相协调,没有产生配位数的连续累积损失。

A series of cyclic biaxial tests under both drained and undrained conditions were performed on dense sand. A statistic code was developed with Fish language to study the evolution of fabric parameters. The relationship between macro mechanical properties and micro parameters such as coordinate number, contact orientation and contact forces could be achieved in this way. The mechanism of induced anisotropy, dilatancy, shear softening and cyclic mobility was discussed from the viewpoint of micro-mechanism. It was indicated that there was compatibility between fabric anisotropy and force anisotropy and no cumulative loss of co-ordination number during cyclic loading.