【摘要】 2017年6月24日,四川省茂县叠溪镇新磨村突发特大滑坡碎屑流灾害,造成大量人员伤亡及房屋损坏,针对该滑坡特征及成因机制,相关学者已经取得一定研究成果,然对其动力学过程与特征的认知还相对缺乏。为解决这一问题,本文引入兼具欧拉算法和拉格朗日算法优势,适用于大变形及长距运动模拟计算的物质点法进行模拟分析。通过分析滑坡全程位移时程曲线、速度时程曲线和等效塑性应变变化特征,揭示其动力演化过程。现场调查与模拟结果表明,崩滑体启动后呈整体运移,与下方坡体碰撞解体,转化为碎屑流,不同时刻同一位置的坡体形态、质点等效塑性应变发展趋势以及能量时程变化曲线均进一步反映碎屑流碰撞破碎和刮铲侵蚀的过程。数值模拟计算与Scheidegger提出的理论计算方法获得的碎屑流速度特征吻合,可以在一定程度上反映滑坡的致灾能力。模拟结果综合反映了滑坡启动及动力演化过程。更多还原

【Abstract】 On June 24,2017,a tremendous debris flow disaster occurred in Xinmo village,Diexi town,Maoxian county,Sichuan province,China. Approximately 2. 87 × 10~6 m~3 rock mass collapsed and the debris buried Xinmo Village,causing a large number of casualties and damages to houses. On the issue of the characteristics and formation mechanism of the landslide,relevant scholars have obtained certain research results in their researches.However,scientific comprehension is relatively lacking about dynamic processes and characteristics of this landslide. This paper introduced two-dimensional material point method( MPM),which combines the advantages of Langrangian and Eulerian algorithm,and is applicable to simulate mechanics with large deformation,to clarify this phenomenon. In the MPM simulation,the kinematic processes of the landslide were revealed through the analysis of time evolution of motion,velocity profile and contour of effective plastic strain. The overall duration time of motion and travelling distance were consistent with reality. Moreover,the results of simulation also suggested that rock mass moved as a whole at startup stage,and then translated into debris flow soon as the result of intense collision. In addition,the results can further reveal the process of debris flow collision and scraper erosion by comparing the slope morphology,the equivalent plastic strain development trend and the energy time history curve on the same position at different times. It showed that two-thirds of gravitational potential energy exhausted in the above processes,which revealed the energy dissipation capacity of collision and erosion. According to crushing collapse dilatancy and entrainment in travelling,the final volume of debris flow was far more than the initial rock mass. Furthermore,slide velocity obtained from numerical computation was basically consistent with the results calculated by the method of Scheidegger. It can be seen that the simulation results provide comprehensive information on the initiation and the dynamic evolution of the landslide.更多还原