地震动力作用触发的斜坡崩滑响应研究——以青川东河口滑坡为例

Study of Collapsing-Sliding Response of Slope Triggered by Seismic Dynamic Action——Taking Donghekou Landslide for Example

同时考虑水平、竖向加速度和两者之间时差对斜坡体破坏作用的研究较少见.运用UDEC对青川东河口斜坡体在具地域性和空间非均质性的地震纵横波时差耦合作用下产生损伤和崩滑破坏的全过程进行了模拟,确定了该斜坡体在水平和竖向地震力作用下产生崩滑破坏的成灾机制及主控因素.结果表明：在输入地震动力条件7~10 s内,坡体后缘形成动力损伤并完全开裂,而横波由于传输速度较慢在26 s时才到达斜坡体,故坡体初期崩滑破坏是受到源自初始震源的纵波产生的水平拉裂作用所致,而后期的抛射和碎屑流动则是受到纵横波耦合作用所致;此外,纵波产生的水平拉裂作用是触发斜坡体产生初期崩滑破坏的主控因素,而斜坡所处地形则是促使其开裂后形成后续碰撞解体、碎屑流动和堆积等运动过程的主控因素.

Study of slope response triggered by action of horizontal and vertical seismic acceleration and their time difference seldom appears.Collapsing and sliding response of Donghekou slope in Qingchuan County and its running out process triggered by single and combined action with time difference,regionality and spatial heterogeneity of horizontal and vertical seismic loads generated by P and S seismic waves is simulated by applying UDEC software;and formation mechanism and key controlling factors of slope collapsing and sliding process are confirmed.The result shows that initial collapsing and sliding of the slope is triggered by horizontal tension action caused by P seismic wave from initial focus for the reason that slope damage and full fracture appears within 7-10s after P seismic wave arriving;but S seismic wave arriving affer 26s because of its lower speed.On the other hand,ejecting and flowing of the broken slope mass is triggered by combined action of P and S seismic waves.In addition,horizontal tension action of P wave is the key controlling factor inducing the slope collapsing and sliding,nevertheless slope topography is the key controlling factor leading to collision,debris flow and accumulation of the slope mass fractured in latter process.