强震作用下顺层岩质斜坡动力失稳机制及启动速度研究

岩质斜坡地震稳定性评价和地震滑坡启动速度计算是边坡地震失稳防治中的难点。结合5?12四川汶川地震诱发的大型高速滑坡，重点以唐家山高速滑坡为例，提出强震作用下中陡倾顺层岩质斜坡动力失稳机制为拉裂－楔劈－滑移－剪断，并着重阐述了拉裂面形成机制、“楔劈”岩块的杠杆作用和碎屑岩块的滚动摩擦效应。对应于该失稳模式，采用弹性力学理论，推导出地震作用下顺层岩体斜坡锁固段的破坏判据和突发剪断时锁固段岩体的形变能公式。考虑锁固段岩体形变能释放的优势方向，运用能量转化原理，给出了更为合理和精确的顺层岩质滑坡突发启动速度公式，进而确定滑坡启程速度。其研究结果为滑坡灾害范围和冲击损害程度提供有效定量计算方法。

Study of kinetic failure mechanism and starting velocity of consequent rock slopes under strong earthquake

Evaluation of seismic stability of rock slopes and the calculation of starting velocity of earthquake-induced landslide are always difficulties for prevention of seismic failure of rock slopes. Combined with the large-scale high-speed landslides induced by 5.12 Wenchuan earthquake, taking Tangjiashan high-speed landslide for example, the kinetic failure mechanism of consequent bedding rock slopes under strong earthquake is proposed. The kinetic failure mechanism includes four stages: tension fracture– wedge splitting–sliding–shear breaking. And the formation mechanism of tension rupture, the leverage of wedge splitting rock masses and the its rolling friction effects of clastic stone, are described in detail. Using the elasticity theory, the failure criterion of locked–up segment of consequent bedding rock slope under earthquake is deduced. And the calculating formula of deformation energy of locked–up rock masses, while the locked-up segment is sharply cut off under earthquake, is also deduced. Considering the advantage releasing direction of locked-up rock masses deformation energy, the energy conversion principle is applied to propose a more reasonable and accurate burst starting velocity formula of the consequent bedding rock landslide, further determining the departure velocity of landslide. The formula provides an effective quantitative calculating method on the hazard scope and impact damage extent of landslide.