降雨型与地震型滑坡试验研究

RESEARCH ON SIMULATION TEST OF RAINFALL-INDUCED LANDSLIDE AND SEISMIC LANDSLIDE

为了研究和探索降雨和地震诱发滑坡灾害的成因机理,对降雨型滑坡和地震型滑坡进行了物理模拟试验,系统地研究了坡度、坡体结构、降雨量、振动强度等因素对斜坡破坏变形的影响规律,探讨了降雨和地震诱发斜坡失稳破坏的主要模式和过程。对于降雨型滑坡,通过实验确定不同坡度滑坡的临界降雨量,发现临界降雨量与滑坡坡度呈幂指数关系。对于地震型滑坡,实验得出坡体的破坏程度与坡体的角度、振动的持续时间、振动的强度成正比;通过实验数据分析土质和岩质滑坡的坡度与振动破坏时间的关系;对汶川地震滑坡统计分析发现,当地震震级达到4级以上时,坡度>30°的滑坡发生的概率较大,模拟试验结果与实际现象基本符合。

In order to study the genetic mechanism of the geohazards induced by rainfall-induced landslide and seismic landslide, the influence of the factors such as the texture of the slope, shape of the slope, vibration intensity, critical rainfall amount, on the slope failure is discussed, and the main models and processes of the slope failure under rainfall and earthquake are investigated, by the means of taking on-site simulation test for rainfall-induced landslide and seismic landslide. For rainfall-induced land- slide, the critical rainfall amounts are determined for slopes of different angles. It is found that the critical rainfall amount and the slope angle follow logarithmic distribution. For seismic landslide, the slope failure extent is proportional to the angle of the slope, duration of vibration and the vibration in- tensity. The relation between landslide slope gradient and earthquake failure time is analyzed accord- ing to experimental data. It has been found by statistical analysis of landslides induced by the Wen- chuan earthquake that the possibility of occurrence of landslide is greater in the slope with gradient greater than 30 degrees when the earthquake magnitude is above 4. The results of simulation experi- ment substantially meet the actual situation.