复合型滑坡是推移式和牵引式的组合,既有牵引式滑坡的特点又有推移式滑坡的性质,通过对复合型滑坡形成机理的研究,揭示了复合型滑坡具有前部牵引—后部加载—中部滑带剪断贯通—最终整体滑移失稳的变形破坏模式,对应地将复合型滑坡分为3个区前缘启动区(牵引作用)、中间主滑区、后缘启动区(加载作用)。针对不同区的破坏形式和受力特点,以及不同区之间的相互作用过程,建立了准确合理的地质力学计算模型,对不同区推力进行详细的计算推导。在推力计算过程中,复合型滑坡推力计算具有区段针对性,前缘启动区和后缘启动区需要考虑与中间主滑区之间的相互作用,而中间主滑区的稳定性是对整个滑坡起主导作用,在计算推力时,既要考虑前缘启动区阻滑段的缺失又要考虑后缘启动区的加载效应。以典型复合型滑坡为例,通过计算充分说明此推力计算方法的合理性,为复合型滑坡防治工程设计提供计算方法。

Complex landslide is the combination of load-caused landslide and retrogressive landslide, with the characteristics of both load-caused landslide and retrogressive landslide. Through research on the formation mechanism of complex landslide, we reveal that complex landslide successively experiences the failure modes of retrogression in the front side, load in the backside, penetration of slip zone in the middle, and finally global sliding instability. Correspondingly, we divide complex landslide into three zones start area in the leading edge (tractive effect), main slide area in the middle, and start area in the trailing edge (loading effect). According to the failure modes and mechanical characteristics of different areas, as well as the interaction among these areas, we establish a calculation model of geomechanics, and derive the thrust of the three areas in detail. The thrust calculation for different areas should be specific. For the calculation of leading edge start area and trailing edge start area, their interactions with the main sliding area should be considered. And the stability of the main sliding area plays a dominant role in the whole landslide. It is necessary to consider the absence of slide-resistance of the leading edge start area and also the loading effect of the trailing edge start area. Calculation example of a typical complex landslide proves the rationality of the thrust calculation method. This research provides a reference for the prevention and control of complex landslide.