震裂-滑移式崩塌形成机制及变形规律研究

以四川省S303线卧龙至巴郎山段K70+340～K70+388处崩塌为研究对象，采用地质力学分析和UDEC离散元模拟相结合的方法，揭示了震裂-滑移式崩塌形成机制及其变形破坏规律。结果表明：该类型崩塌主要发生在有陡倾结构面的顺层岩质斜坡；地震波对斜坡岩体主要为拉剪破坏，并呈现出坡顶和坡面处拉应力大于坡体内部的规律；地震力对斜坡的影响表现出顶部较下部、坡面较坡内变形快、变形量大的特点；随地震波加速度的幅值的增大，斜坡动力响应也越强烈，崩塌体的位移也越大；震裂破坏过程可以归纳为6个阶段，即（1）地震作用下岩体的损伤和拉张裂缝的形成；（2）拉张裂缝的拓展和软弱滑移面的贯通；（3）崩塌体整体震散和局部岩块的滑移；（4）局部岩块失稳，产生岩体的坠落、弹射、抛射和滚落现象；（5）岩体整体产生坠落、弹射、抛射和滚落；（6）崩塌体趋于稳定。该问题的研究不仅可以为地质灾害的分析提供新方法，而且对震区防灾、减灾具有一定的指导意义。

Research on formation mechanism and deformation law of shattering-sliding collapses

This paper investigates the formation mechanism and deformation law of earthquake-induced shattering-sliding collapses induced by studying the collapse at K70+340-K70+388 of S303 highway from Wolong to Balangshan in Sichuan province, using the combination of geomechanical method and the simulation of discrete element method UDEC. It is shown that: these collapses mainly occur in bedding slopes with steep joints; the seismic wave leads to a tensile-shear failure to the slope; and the tensile stress at dome of the slope is greater than that inside the slope; deformation induced by seismic force is found to be faster and greater at the upper and dome of the slope than that at the lower and interior of slope; the higher amplitude of seismic acceleration is, the greater slope dynamic response is, and the larger displacement of collapse mass. The failure process of shattering-sliding collapse can be divided into six stages, 1) rock mass damage and tensile fractures formatting under earthquake; 2) tensile fractures expansion and coalescence of weak slip plane; 3) the whole slump-mass scattered and local rocks slip; 4) local rocks fall, ejection, mass ejection and tumble; 5) rock mass fall, ejection, mass ejection and tumble; 6) slump-mass tends to be stability. Therefore, this research provides not only a new method for geological hazard analysis, but also a significant guide to disaster prevention and mitigation in earthquake region.