采用FLAC3D的互层土基坑突涌破坏判断方法

Study on Judgment Method of Surge Damage of Interbedded Soil Foundation Pit Based on FLAC3D

运用数值模拟方法,模拟了互层土基坑中坑底突涌的发展过程:在开挖互层土层上覆粘土层时,基坑整体处于稳定状态,仅顶部部分区域出现塑性屈服,达到突涌不稳定状态;在开挖互层土层时,土体的塑性区域不断向下方发展,最终以一定角度与下方砂层塑性区贯通,基坑发生突涌。认为数值模拟应以塑性区贯通作为突涌发生的判定标志。

Using numerical simulation method, the development process of pit bottom gushing in inter-bedded soil foundation pit is simulated: when excavating the overlying clay layer of interbedded soil, the whole foundation pit is in a stable state, and only the top part of the pit yields plastic ally, thus reaching the unstable state of gushing;when excavating the interbedded soil layer, the plastic zone of soil continues to develop downward, and eventually penetrates the plastic zone of the sand layer below at a certain angle, and the foundation pit gushing occurs. It is considered that the penetration of plastic zone should be taken as the criterion of gushing occurrence in numerical simulation.