高速岩质滑坡碰撞运动参量及其堆积体地质结构特征研究

High-speed rock landslide is a kind of serious geological hazard, the calculation of its motion parameters and stability analysis of its deposition have always been the difficulties of landslide kinetic research and disaster prevention and mitigation design. The collision between high-speed rock landslide and terrestrial obstacles not only restricts movement, scope and geological structure of the sliding masses, but also affects the stability of the deposition. The project would firstly carry out field geological investigations on some typical high-speed rock landslides, then interpret and depict the whole movement process and geological model by analyzing geological conditions and deposition structures. Based on these materials, constitutive relation and dynamic parameters of rock mass could be obtained firstly through Hopkinson Pressure Bar experiments. In addition, motion parameters of the sliding mass could be captured by non-contact digital image displacement identification technology in collision physical model experiments. Furthermore, the energy dissipation mechanism of sliding masses during collision would be comprehensively revealed by acoustic detection for rock damage and microscopic observation. In order to deeply delve controlling effect of collision factors to motion parameters of the landslide body and geological structure of deposition, the spatial distribution of deposition after collision would be measured. With the aid of Multi-rigid-body System Dynamics method, the geomechanics collision model of rock landslide would be established. Through calculation of the model and multi-scale numerical simulation, the energy loss value and the motion parameters (velocity and displacement vector) of sliding body, due to collision, are determined, also, the correspondence between geological structure features and stability is established. This study will provide calculating method and practical guidance for high-speed landslide disaster prevention and mitigation.

高速岩质滑坡运动参量的计算和堆积体的稳定性评价一直是滑坡动力学研究和防灾减灾设计的难点。而高速岩质滑体与地物的碰撞行为不但制约其运动方式，致灾范围和地质结构，而且影响堆积体的稳定性。本研究选取高速岩质滑坡典型实例，通过野外地质调查，分析滑坡赋存地质条件和堆积体结构特征，准确刻画滑坡运动全过程的地质模型。在此基础上，基于霍普金森杆实验和碰撞物理模型试验，采用数字图像位移识别、损伤声波检测和显微镜观察等技术，获取岩石本构关系和动力参数，捕捉滑块的运动参量，深入揭示滑体碰撞能量耗散机制。进行撞击后堆积体空间分布形态测定，深入探究碰撞因素对滑体运动参量和堆积体地质结构的控制效应。借助多刚体系统动力学研究方法，构建岩质滑体碰撞地质力学模型，通过分析计算和多尺度数值模拟，确定滑体碰撞能量损失及运动参量（速度和位移矢量），并建立地质结构特征与稳定性的对应关系。为高速滑坡防灾减灾提供计算方法和实际指导。

摘要： 2008年“5.12”汶川大地震造成四川地区大量高速岩质滑坡。由于滑坡赋存地质条件、坡体结构、岩体结构、岩体物理力学性质、沿途地形、接触介质及撞击方式的不同，造成各个滑坡运动方式和致灾范围迥异，进而影响堆积体的稳定性和抢险救灾方案。.对汶川地震重灾区内北川唐家山滑坡、苦竹坝滑坡、肖家河滑坡和青川窝前滑坡等高速岩质滑坡开展了野外调查，对比原始斜坡和堆积体的物质成分、块度系数和地质结构特征，还原解译滑坡运动碰撞碎裂过程。通过物理模型试验，研究了滑体尺寸、撞击速度、撞击方式对滑体滑距、滑动方向和堆积体地质结构的影响效应。并探讨了不同地质结构滑坡堰塞坝在越顶溢流的破坏规律。获得的主要研究结果包括：.（1）脆性岩质滑坡撞击碎裂地质模型.现场调查发现高速短程岩质滑坡往往呈现前部和侧边破碎严重，中部较为完整的结构特征。考虑局部破裂和动量传递等因素，建立了滑体二维撞击碎裂地质模型，很好地解释了碰撞碎裂形成的高速碎屑流、并推到了其撞击后的运动速度和最终滑距。通过对该模型敏感性分析，得到撞击角度和滑体尺寸为高敏感因素，单轴抗压强度为中等敏感因素，坡高为低敏感因素。.(2) 高速岩质滑坡碰撞动量传递效应和碎裂机理.采用室内物理模型试验，发现滑体碰撞速度、滑体纵横比（高径比）与岩石碰撞破坏程度呈正相关；碰撞造成滑体内部结构损伤，力学强度降低；碰撞碎裂和动量传递共同作用有可能使滑体滑距增加。 .(3) 脆性岩石高速滚动摩擦特性及摩擦碎裂机理.开展不同压力和转速条件下干燥和湿润石灰岩的高速滚动摩擦试验。发现滚动摩擦系数和磨损率与摩擦速率存在线性关系。基于Hertz弹性接触理论，推导出摩擦斑处的最大压应力和拉应力，提出脆性灰岩的摩擦碎裂机理。. (4) 滑坡堰塞坝越顶溢流破坏机理.堰塞坝漫顶溃坝主要分为渗流、漫顶、冲刷和溃决4个过程；坝体堆积颗粒级配越差，坝体允许渗流坡降越小；漫顶溃坝时溃口尺寸与蓄水量正相关。.研究成果可为高速滑坡防灾减灾提供科技支撑和实践指导。