Mechanism of progressive failure of saturated heavily overconsolidated clay/dense sand based on experiments and soil-water coupled deformation analysis

本文介绍了密砂室内渗透破坏试验的数值模拟结果。分析涉及三种排水条件：不排水、部分排水和完全排水。密实砂土地基由于超静孔压梯度引起的有效应力减小而达到失稳。当密实砂快速加载（不排水条件），然后保持荷载，砂体内部的条件变化到排水条件，最终导致渐进破坏。这种行为类似于地震后液化的发生。在不排水条件下，RPFEM不能用于预测密砂的破坏。而土-水耦合变形分析在这一过程中能够做出令人满意的预测。

This research describes the numerical simulation results of the laboratory seepage failure experiment on dense sand. The analysis was concerned with three drainage conditions : undrained, partially drained and fully drained. The dense sand ground reaches the instability due to diminishing effective stress that resulted by the excess pore pressure gradient. When the dense sand is loaded rapidly (undrain condition) and afterwards the load is held, the condition within the sand mass changes to drained condition finally resulting the progressive failure. This behavior is similar to the occurrence of Liquefaction after an earthquake. The RPFEM cannot be used to predict the failure of dense sand under undrained condition. However, the soil-water coupled deformation analysis is capable of making satisfactory predictions in such a cade.