软土卸载孔压特性的试验与理论计算分析

Pore pressure characteristic analysis of soft clay during unloading based on lab data and numerical calculation

摘要: 在理论分析和试验的基础上 ,对软黏土的卸载孔压特性进行了研究。研究显示 :在伸长条件下 ,孔压先由零逐渐发展到负的最大值 ,然后又逐渐减小至零 ,突破零位后 ,发展成为正孔压并最后达到正的最大值。围压越大 ,产生的负孔压的极值越大 ,最终的正孔压越小。室内试验显示 ,如果忽略短暂的负孔压阶段 ,归一化孔压与主应变成较好的二次关系 ,且归一化孔压与主应变所成的二次关系与卸载路径关系密切。

Abstract: The pore pressure characteristic of soft soil during unloading is studied based on the numerical calculation and lab data.The research indicates that, the pore pressure changed from zero to the maximum negative value. If the negative water pressure is ignored because of its short lasting time and small value, lab tests show that the relationship between the normalized pore pressure and the principal strain is a quadratic curve. Furthermore, the secondary curve is closely related to the unloading path.