高速远程滑坡流态化运动的力学作用机制及动力学模型研究

Fast-moving landslides are characterized by extremely high speed, extraordinary mobility and have a strong ability to cause disasters, which pose a threat to the safety of major projects construction and human settlements. At present, the difficulty to predict and evaluate fast-moving landslide hazard lies mainly in two aspects, on one hand, the fluidization mechanism of fast-moving landslides is complex, on the other hand, the development of quantitative dynamic model of fast-moving landslides is difficult. To this end, the project adopts the methods of field investigation, theoretical analysis, laboratory test and numerical simulation to study the fluidization mechanism and dynamic model of fast-moving landslides in the upstream of the Yellow River. The main research contents include: (1) Find out the field geological evidence of the fluidized motion of fast-moving landslide and establish the landslide geological model. (2) Analyze the action modes and characteristics of the Coulomb-like friction resistance and the rheological resistance of the landslides，and analyze the dynamic response law between the two resistance and its influencing factors (sliding speed, thickness, etc.). Study on the special drag reduction effect that leads to the ultra-high fluidity at landslide substrate, reveal the mechanism of fluidized motion of fast-moving landslides. (3) Theoretically deduce the mechanical equations and parameter expressions of the driving and resistance force on landslides and establish a dynamic model of fast-moving landslides based on the consideration of the complex resistance. This study analyzes the fluidization mechanism and develop the quantitative dynamic model of fast-moving landslides from the perspective of complex resistance. The research perspective is novel and the content is innovative and the expected results have certain scientific significance and practical value for disaster prevention and reduction of fast-moving landslides.

高速远程滑坡具有极高的速度、超常的流动性，在传输巨大能量的同时，极具破坏力，对重大工程建设和人居安全构成严重威胁。目前，高速远程滑坡灾害难以预测评价主要体现在两方面，一是滑坡流态化运动的力学作用机制复杂，二是发展量化动力学模型难度较大。为此，本项目对黄河上游高速远程滑坡流态化运动的力学作用机制及动力学模型开展研究。（1）查明滑坡流态化运动的野外地质证据，建立地质模型；（2）分析滑坡内部摩擦阻力和流变阻力作用的模式和特征及其与影响因素（滑体速度、厚度等）的动态响应规律，研究滑体基底超高流动性的特殊减阻效应，揭示高速远程滑坡流态化运动的力学作用机制；（3）理论推导滑坡驱动力和各阻力的力学方程和参数表达，建立考虑复合阻力作用的高速远程滑坡动力学模型。本研究从滑体内部复杂作用力的角度分析滑坡流态化运动机制，发展动力学量化模型，研究视角新颖，内容创新，成果对防灾减灾具有一定的科学意义和实用价值。

高速远程滑坡具有极高的运动速度、超常的流动性，携带巨大的能量且极具破坏力，易引发灾难性事故，一直是国际学术研究的前沿和难点问题。目前研究中提出的理论、经验和数值模型的精确度难以满足高速远程滑坡防灾减灾的技术要求。本项目围绕高速远程滑坡流态化运动机制和动力学模型开展研究，主要内容包括：高速远程滑坡成因和堆积物形态特征；滑坡基底摩擦阻力模型；滑坡运动的流变阻力模型；考虑复合阻力的高速远程滑坡动力学模型及验证。主要结论和成果如下：（1）揭示了高速远程滑坡孕灾机制，加深了对高速远程滑坡成因机制的认识；（2）查明了戈龙布滑坡堆积体分布特征，揭示了高速远程滑坡反粒序堆积、层序堆积、体积效应等流态化运动基本特征；（3）提出了高速远程滑坡地质力学理论模型，完善了滑坡运动过程中的力学作用过程的理论描述；（4）提出了高速远程滑坡驱动力模型，复合阻力中的基底摩擦阻力和流变阻力的解析力学模型，可被实际工程计算中选用；（5）建立了滑坡碎屑流物理模型试验，揭示了滑坡碎屑流缩尺运动过程特征和滑体颗粒尺度力学作用机制；（6）重构了戈龙布滑坡滑动前后地质力学模型，应用Rapid-LS反演分析了滑坡动力学过程，对比验证了滑坡动力学模型Rapid-LS的可靠性。本项目从基础研究的层面很好的补充了滑坡动力学理论，进一步发展完善了滑坡动力学的数值模型，形成的成套研究成果可应用于峡谷地区高速远程滑坡等突发性地质灾害的预测、预警与风险防控，具有一定的理论价值和应用前景。