【作者】 宋新远；

【导师】 邢爱国；

【作者基本信息】 上海交通大学 ， 防灾减灾工程及防护工程， 2009， 硕士

【摘要】 岩土体在一定的自然或人为条件下会诱发滑坡。滑坡体在高速入水时会产生涌浪,大型滑坡所激起的涌浪会对沿岸地区的居民和基础设施造成重大危害。同时,滑体堆积于河道中,堵塞河道形成堰塞湖,由于堰塞体的不稳定性及水位上涨等因素,极易造成溃坝这一滑坡次生灾害,必然会危及到下游地区的安全。因此,本文借用当前发展比较成熟的计算流体动力学(Computational Fluid Dynamics,简称CFD)技术对滑坡涌浪及溃坝灾害进行数值模拟,以期为滑坡灾害的预防和治理措施的制定提供一定的科学依据。本文采用有限体积法对描述水流运动的紊流模型和描述自由水面运动的方程进行离散建立了二维数学模型,然后基于FLUENT软件对滑块体竖直入水过程中所产生的涌浪及其传播过程进行了模拟研究,模拟结果与实体模型试验结果吻合较好。本文利用该模型进一步研究了涌浪自由面变形特征、速度涡量场以及压力场的变化特征。滑坡涌浪过程复杂,影响因素众多。本文选取了水深、滑体滑速以及滑体体积这三个重要的因素,分析了在三种不同因素下涌浪自由面变形、涌浪高度和速度场的变化规律。研究结果表明:该数值模型对大体积、沿陡峭斜坡的滑坡体高速入水(水库或河流)所引起的涌浪灾害问题有一定的参考价值。本文模拟分析了滑坡引发的另一类次生灾害-溃坝。本文首先与溃坝模型试验结果做比较来验证模型的可靠性,接着分析了溃坝波传播过程中遇到障碍物时的反射、流体的飞溅、融合等现象。进一步模拟了在瞬时全溃和局部溃决两种溃坝形式下水体自由面变化以及流速变化特征。最后,本文以易贡堰塞湖溃坝为实例,分析了溃坝洪水在下游弯曲河道的演进过程及不同位置的流速变化。数值模拟结果与实测资料所记录的现象基本一致,再现了易贡湖溃坝后洪水的演进过程,同时表明该模型能够近似地模拟出溃坝后洪水在地形复杂弯曲河道中的演进过程。本文的研究内容对大型滑坡所引起的涌浪灾害、溃坝灾害的预防具有一定的实际工程意义与参考价值。更多还原

【Abstract】 The rock and soil mass can induce landslide under natural or artificial conditions. The landslide produces waves after entering the water, and the water waves generated by large scale of landslides can cause great danger to the dwellers and infrastructures around the rivers or lakes. At the same time, the slide blocks pack in the river and block the river which causes the barrier lake. With the instability of the damming body and the rising of water level, the secondary disaster dam-break is likely to be caused, and is bound to endanger the safety of the lower reaches. So, this paper uses the current relatively mature CFD technology for the numerical simulation study to the landslide hazard. In order to provide the disaster prevention and the control measures establishment with some relevant scientific basis.In this paper, the finite volume method is used to discrete the equations which describe the turbulent flow model and the water surface movement model and establish two-dimensional mathematical model, via the software FLUENT, this text simulate the surge waves and its propagation process during the slide vertically into the water, by contrasting the numerical results with the previous entity model test results, the comparison results are very satisfactory. Further more, the model is used for the study of the free surface deformation characteristics, the vortex field as well as the changes of pressure field. The process of surge waves generated by landslides is very complex, and the influencing factors are numerous, this text selects three important factors: water depth, sliding velocity and the slide volume, analyzing the change law of the surge free surface deformation, the wave height and the velocity field under the three different factors. The results show that the numerical model can provide the analysis of surge generated by large volume slide along the steep slopes with the high-speed into the water (rivers or reservoirs) with a certain reference value. This text then simulates and analyzes another secondary disaster dam-break caused by landslide. Firstly, through the comparison with the dam-break model’s results, this text verify the reliability of the model, the comparison are basically consistent, in succession, this text analyzes the dam-break waves reflection when encountering the obstacles, the fluid spatter, integration and so on. Further more, this text simulates the change characteristics of water free surface and the flow velocities under the whole and local dam-break. Finally, this text takes the dam-break of Yigong Barrier Lake as an example for analysis of the dam-break floods evolution in downstream river course and the velocity changes at different sites. The simulation results are consistent with the observed data, which reappears the flood evolution process after dam-break of Yigong Barrier Lake, at the same time; it shows that the model can simply simulate the flood evolution in the river bend with complex terrain after dam-break, the study can provide the disater prevention of the surge and dam-break disater which caused by large-scale landslides with a certain practical significance and reference value.更多还原