南方极端冰雪灾害条件下边坡崩塌机理初步研究

Preliminary research on formation mechanism of collapse under the condition of extreme snow hazard

针对2008年初我国南方罕见的极端冰雪条件下的岩土坡体崩塌问题,运用岩土体的水分场、温度场及应力场三场耦合基本理论,采用FLAC3D模拟软件,对饱和状态下的岩质边坡进行数值模拟计算,从冻结深度及冻胀变形两个方面揭示了南方极端冰雪灾害条件下崩塌形成机理。计算结果表明,短时间内冻结仅仅发生在岩土体表层;在冻结过程中,边坡表层质点发生了向自由边界的位移,随着冻结时间的延长,冻胀位移有增大的趋势。边坡岩土体的冻融损伤只发生在边坡表层,因此南方极端冰雪环境下边坡多发生浅层崩滑破坏,并给出了相应崩塌形成的过程示意图。

In order to discuss the problem of soil - rock body collapses in the condition of rare extreme snow climate in the beginning of 2008 in southern China, the basic theory of three fields coupling of water - heat - mechanics and the software FLAC3D are applied to simulate the saturated slope. The formation mechanism of collapse is revealed from freezing depth and frost heaving deformation under the condition of southern extreme snow hazard. The results show that freezing only occurs on the slope surface in the preliminary short time; in the process of freezing, the surface displacements move to the free boundary of the slope, and increase with the time. The freeze - thaw damage of slope only occurs on the slope surface, therefore the condition of extreme snow hazard only causes shallow collapse and sliding destruction to the slope. The graphics of collapse＇s formation process under the condition of extreme snow climate are provided.