|Alternative Title||Numerical Study on Generation Processes and Near-Field Characteristics of Landslide Induced Impulse Waves|
|Place of Conferral||北京|
|Keyword||滑坡涌浪 近场特征 水土耦合 光滑粒子动力学方法 数值模拟|
1．将滑坡体简化为刚体，应用N-S方程改进以往用浅水方程描述复杂流体运动的缺陷, 采用基于拉格朗日描述的光滑粒子流体动力学(SPH)方法，建立了块状刚体滑坡涌浪的三维流固耦合数值模型，能够合理模拟滑坡体与水体相互作用诱导涌浪的全过程，并得到了典型实验结果的良好验证。将模型应用于荒田滑坡涌浪实际问题,很好地再现了荒田滑坡涌浪的产生和演化过程, 给出了荒田滑坡涌浪主要特征和爬升过程的定量结果。并对涌浪在深V河道里的近场特征进行了分析。
Landslides may generate large impulse waves in lakes or reservoirs, which have a high potential to cause direct damage to the reservoir buildings and residents, and even result in the loss of life. The accurate estimation of the landslide-induced wave hazard is still an open problem because of its complexity. Suitable fluid-solid coupling models are developed here to simulate the interaction between the landslide and water. Focus on the the generation process and near-field characteristics of landslide induced impulse waves, we have discussed the generation mechanism of impulse waves, wave type and three dimensional charateristics of the leading wave, and the effect of complex boundary condition on the near-field charateristics. The main contents of this dissertation are as following:
1. A 3D solid-fluid coupling model is developed to simulate the impulse waves generated by a rigid body. Based on the smoothed particle hydrodynamics (SPH) framework, this model, using Navier-Stokes equations, can be much better than shallow water equations when simulating the complex flow field. Two typical experiments are used to validate this model and a good agreement about the whole generation process is observed. Then the model is used to study the initial wave in Huangtian landslide event. The complete three-dimensional evolution of the initial wave is obtained and its quantitative results, including the runup process, are obtained. The near field characteristics of impulse waves generated in a deep-V channel is also studied.
2. A newly-developed 3D soil–water coupling SPH model is developed to simulate the generation of a landslide-induced impulse wave. To simulate the large deformation and failure flow of the landslide, an elasto–plastic constitutive model is included. It’s the first time to realize the soil-water coupling simulation about the impulse waves generated by a complex deformable landslide, helpling to obtain the generation mechanism of the impulse waves. Comparison with non-Newtonian fluid model shows the better physical principles and simulated precision of our model. Also the influence of the dilatancy angle of soil is found to be non-negligible.
3. Using the solid-fluid coupling SPH model, the charateristics of the leading wave is studied carefully. The wave type of the leading wave and its charateristics (wave height, wave velocity, wavelength et al.) is analyzed on different initial conditions including different impact Froude number and relative slide thickness. Energy transfer process is also studied and the high relativity between the crest value of mechanical water energy and nonlinearity parameter Ursell number is obtained. Then the criteria of wave type classification based on different parameters are studied.
4. Using the soil-water coupling SPH model, we have simulated the whole process where landslides rush in to a 3D fjord river channel. Because of the limited boundary of the channel, the generation and evolution processes have special 3D near-field characteristics. Focusing on the process of propagation to the opposite shore and later runup, the channel is separated into relative wide and relative narrow based on the existence of decline stage. The amplitude decline function of the leading wave propagating along the relative narrow channel is also obtained. Analysis of detailed near field wave characteristics shows that the formation and magnitude of the initial wave are strongly constrained by topography in the fjord channel. The different amplitude between the near field waves which propagate along the river and the namely initial wave is analyzed, which is helpful for accurately predicting the leading wave.
|石传奇. 滑坡涌浪产生过程及近场特征的数值研究[D]. 北京. 中国科学院大学,2018.|
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