滑坡涌浪流–固耦合分析方法与应用  

Fluid-solid coupling method of landslide tsunamis and its application

作　　者：徐文杰[1] XU Wenjie(State Key Laboratoty of Hydroscience and Hydraulic Engineerings Tsinghua University,Beijing 100084,China)

机构地区：[1]清华大学水沙科学与水利水电工程国家重点实验室,北京100084

出　　处：《岩石力学与工程学报》2020年第7期1420-1433,共14页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(51879142,51679123);清华大学水沙科学与水利水电工程国家重点实验室资助项目(2020–KY–04)。

摘　　要：滑坡涌浪是自然界中广泛存在的一类复杂的流–固耦合问题。针对现有滑坡涌浪数值计算分析方法中的不足,立足于滑坡涌浪动力学过程及物理机制,充分利用不同数值计算方法的特点,采用离散元方法(DEM)模拟滑坡体大变形、不连续问题,采用光滑粒子流方法(SPH)模拟水体的流体动力学特性,构建SPH-DEM流固耦合算法。开发面向GPU并行加速的计算分析程序(Co DEM),实现SPH-DEM耦合过程的大规模高性能计算分析。运用所开发的程序,对Fahad开展的散体滑坡涌浪模型试验进行同工况下的数值试验,验证程序在模拟滑坡涌浪流–固耦合问题的可靠性。在SPH-DEM耦合分析时,SPH粒子间距与DEM粒径的比值将影响着耦合精度及计算规模;一般地该值小于1/6时,除了对于滑坡入水点附近的涌浪模拟精确性有一定的影响外,对涌浪在远场(距离入水点超过1个波长)影响较小。以1963年意大利Vajont库区滑坡涌浪灾害为例,基于重构的滑坡体及库区的精细化三维数值计算模型,成功再现了从"滑坡运动→涌浪形成、传播→冲击大坝、漫顶"灾害链全过程。在此基础上,分别从滑坡体最终堆积形态(相似度在90%以上)、漫顶最大洪峰流量(约为350×103 m3/s)及对坝体的最大作用力(约为3.9×1010 N)等方面与已有的研究成果进行对比和分析,均表明所研究成果与已有成果吻合较好。研究表明,SPH-DEM耦合方法可以较好地实现滑坡涌浪灾害动力学过程分析,所开发的CoDEM可以为库区及近水岸滑坡防灾减灾提供高效的技术支持。Landslide tsunamis,as a complex type of fluid-solid coupling problems,are widespread in nature and often cause huge catastrophes. Aiming at the deficiencies in existing numerical methods of landslide tsunamis,starting from the dynamic process and physical mechanisms of landslide tsunamis and fully taking advantages of different numerical methods,the large deformation and discontinuity process of landslides and the hydrodynamic process of water were respectively simulated by using the discrete element method(DEM) and smoothed particle hydrodynamics(SPH),and a GPU-accelerated parallel SPH-DEM coupling code,named as CoDEM,was developed to realize large-scale high-performance computing of landslide tsunami simulation. The tsunami model test of a granular landslide performed by Fahad was simulated using the developed code and the reliability of the code was verified. In the SPH-DEM coupling simulation,the ratio of the SPH particle spacing to the DEM particle size will affect the coupling accuracy and the simulation scale. Generally,the ratio less than 1/6 has a certain impact on the accuracy of the tsunami near the landslide entry point while less influence on the far field(more than 1 wavelength from the water entry point). Taking the landslide in Vajont reservoir,Italy in 1963 as an example,the 3 D numerical model of the landslide and reservoir area was reconstructed,and the whole process from landslide movement,formation and transmission of tsunamis to impact on dam and floods was simulated by using the developed SPH-DEM coupling code. According to the numerical results, the final morphology of the accumulation body(similarity larger than 90%),the maximum flood peak flow(about 350×103 m3/s) and the maximum force on the dam(about 3.9×1010 N) were compared with the previous documents,showing a good agreement. The study shows that the SPH-DEM coupling method can well simulate the dynamic process of landslide tsunamis and the developed CoDEM can provide efficient technical support for landslide disaster prevention an

关 键 词：边坡工程 滑坡涌浪 流–固耦合 离散元法(DEM) 光滑粒子流(SPH) 

分 类 号：P642[天文地球—工程地质学]