基于孔隙演化的砂土冲击绝热关系研究

Shock-hugoniot relationships of sand considering porosity evolution

基于砂土多孔、含水的特性,对动载荷作用下孔隙演化对砂土冲击绝热关系的影响进行了研究。基于砂土基体的不可压缩假设,采用单个球形气孔等效模型和广义Mises屈服准则推导了砂土考虑孔隙压实的演化方程;根据冲击Hugoniot突跃条件和Grüneisen型方程,获得了砂土考虑孔隙演化的状态方程;根据混合物冲击波关系和孔隙演化状态方程,获得了砂土基体材料冲击绝热关系、干砂土和湿砂土冲击绝热关系,并与已有实验结果进行了对比。结果表明:计算得到的绝热线与实验数据吻合较好,该孔隙演化状态方程能够较为准确的反映动载作用下砂土的动态响应过程。

Effects of porosity evolution on sand shock-hugoniot relationships under dynamic loading were investigated based on porous and hydrous characteristics of sand. Based on the incompressible hypothesis of sand matrix,using a single spherical pore equivalent model and the generalized Mises strength criterion,the porosity evolution equation of sand was derived. According to Hugoniot jump condition and Grüneisen-type state equation,the state equation of sand considering porosity dynamic compaction was deduced. The shock-hugonoit curves for sand matrix,dry sand and moist sand were gained by using the mixture-shock wave relationship and porosity evolution state equation. Results showed that the calculated shock-hugonoit curves for sand agree well with the available test data in literature; the porosity evolution state equation can more correctly reflect the dynamic response process of sand under dynamic loading.