地震触发砂土液化总应力判别法──以北京密云水库白河主坝震害为例

Ascertainment of sand liquefaction arising from earthquake by the method of comprehensive stress ──Taking seismic damage to Bathe Principal dam of Miyun reservoir in Beijing, China, as an example

在二维应力状态下，地震在土体中不仅产生动水平剪应力τνｈ，而且引起在一般情况下不可忽略的竖向动正应力σｖ及水平动正应力σｈ。在研究地震触发砂土液化的应力条件及液化判别方法时应考虑这三种动应力的联合作用．本文基于莫尔－库伦强度准则，采用总应力方法，研究能够考虑地震动水平剪应力τｖｈ、竖向动正应力σｖ及水平动正应力σｈ共同作用的砂土液化判别准则，并且以北京密云水库白河主坝震害为例，说明这种液化判别准则的有效性及其使用方法。

In the case of two-dimensional plane stress condition, the cyclic stress induced by earthquake in earth includes horizontal tangential cyclic shearing stress, τvh, vertical cyclic normal stress, σy, and horizontal cyclic normal stress, σh. These three components of the cyclic stress are the main factors complicating the procedures for assessing the deformation or stability of earth and earth structures during earthquake. And it is required that the cyclic stress condition and the assessing criterion of sand liquefaction arising from earthquake are researched by thinking over the joint action of them. In this paper, in view of Mohr-Coulomb's strength criterion, the assessing criterion of sand liquefaction arising from earthquake is studies by the method of comprehensive stress, that includes the joint action of horizontal tangential cyclic shearing stress, τvh, vertical cyclic normal stress, σy, and horizontal cyclic normal stress, σh. The effective function and operation method of the assessing criterion of sand liquefaction are demonstrated by the earthquake damage to Baihe principal dam of Miyun reservoir in Beijing, China.