柱状危岩体坐落式崩塌产生涌浪的简化数值模型与校验

Simplified numerical model and verification for the impulse wave generated by situated collapse of a dangerous columnar rock mass

许多水库峡谷区和海岸带存在柱状崩塌,它们可能因为软弱基座的破坏而发生坐落式崩塌,碎屑冲击入水将形成涌浪;快速、准确地预测分析大面积、长距离的该类涌浪问题面临着挑战。将崩塌体-水体耦合作用过程黑箱化,利用物理试验公式形成高精度的初始涌浪产生模型,利用Boussinesq模型控制初始涌浪事件波的传播,构建了一个计算精度与物理试验相近的简化涌浪数值模型3D-LWBM。并对这一数值模型进行了应用校验,结果显示:(1)3D-LWBM模拟的伪二维数值液面和测点水位过程的时序性和精确度都和物理试验结果有很好的一致性,精确度高。(2)在三峡库区龙门寨危岩体复杂地形河道中,3D-LWBM预测了涌浪的产生与传播;与流固全耦合模拟结果相比较,它具有较好的计算精度和极快的计算速度。(3)网格尺寸是初始波长的1/6~1/4时,3D-LWBM可以得到较精确的合理解;同时,3D-LWBM有其自身的适用范围。该研究可为相关涌浪防灾减灾提供技术支撑。

There are columnar collapse in many reservoir gorges and coastal zones, these collapse may be exhibited by situated collapse due to the failure of weak base rock mass. The debris will impact into the water and form impulse waves. It is a challenge to predict and analyze the large area and long-distance impulse wave quickly and accurately. The coupling process of collapse body and water body is black boxed, a high-precision initial surge generation model is formed by using the physical test formula, and the Boussinesq model is used to control the propagation of initial surge event wave. A simplified surge numerical model 3D-LWBM with similar calculation accuracy to the physical test is constructed. The results show that: 1) The timing sequence and accuracy of 3D-LWBM simulation of pseudo-two-dimensional numerical liquid level and measured point water level are in good agreement with the physical experiment results, and the accuracy is high. 2) The generation and propagation of impulse waves are predicted by 3D-LWBM in the complicated topographic channel of Longmenzhai dangerous rock mass in the Three Gorges Reservoir area. Compared with the results of fluid-landslide full coupled simulation, 3D-LWBM has better calculatiion accuracy and faster calculation speed. 3) When the mesh size is 1/6-1/4 of the initial wave length, 3D-LWBM can obtain a more accurate and resonable result. At the same time, 3D-LWBM has its own scope of application. This study can provide technical support for disaster prevention and mitigation of relevant impulse waves.