滑坡涌浪是一种危害较大的次生灾害,会对人民的生命财产安全造成重大威胁。为探究滑坡涌浪在不同场域的涌浪水波特性,及时发现危害并采取防范措施,对滑坡涌浪全程进行数值模拟。通过CFD软件FLOW-3D建立滑坡涌浪数值模型,并将其模拟精度与有效性,与经典滑坡涌浪试验进行验证。对比结果表明数值模拟涌浪首浪高度与物理模型试验结果一致性较好,数值模拟能反映滑坡涌浪传播的整个过程。基于数值模型,制定关于滑坡体密度、滑坡体体积及滑坡体初始入水特征的27组数值模拟试验。结果表明:近场涌浪回弹及首波波谷出现时间与滑坡体密度呈负相关;近场涌浪首波势能占全程涌浪势能的70%左右;远场涌浪周期约为滑坡体水下运动时间的2倍;通过涌浪势能给出了特定条件下距滑坡体入水点22 m处为远场涌浪波起始位置。研究成果为滑坡涌浪灾害的预警和防治提供一定的参考,可避免发生更大灾害,减少损失。

As a secondary disaster with great harm, landslide surge poses great threats to people's life and property safety. In the aim of discovering hazards and taking preventive measures, the whole process of landslide surge wave was simulated numerically to explore the characteristics of surge waves in different fields. A numerical model of landslide surge wave was established by CFD Flow-3D. The accuracy and effectiveness of the model were verified by classical landslide surge wave test. The height of the first wave simulated by the numerical simulation was in good agreement with the result of physical model test, implying that the numerical simulation could reflect the whole process of landslide surge wave propagation. Based on the numerical model, 27 groups of numerical simulation tests on landslide density, landslide volume and initial water entry characteristics were developed. Results revealed a negative correlation between the rebound of the near field surge wave and the occurrence time of the first wave trough and the density of the landslide. The first potential energy of the near field surge wave accounts for about 70% of the whole surge potential energy. The period of the far field surge wave is about two times of the underwater movement time of the landslide body. According to the surge potential energy, the initial position of the far field surge wave is 22 meters away from the water entry point of the landslide under certain conditions. The research findings are of referential value for the early warning and prevention of landslide surge disaster in practice.

滑坡入水淹没率是影响滑坡涌浪生成和传播的重要因素。采用正交试验开展散体滑坡涌浪室内模拟试验研究,探讨了滑体规模、速度与水深条件对涌浪波形特征的影响。取得如下研究成果:①滑体完全入水激发涌浪,首浪具有较大波幅,波前平缓、波后较陡,且波形关于竖直和水平轴对称,呈“匍匐”态传播;未完全入水滑坡涌浪初始波峰明显,形态尖突,无明显波谷,波形关于竖直轴对称。②建立了基于单宽体积比R和弗劳德数Fr的波形分类方法,将涌浪分为类斯托克斯波、类椭圆余弦波(或类孤立波)和涌波3种波形,界定了基于R-Fr关系的波形边界方程。③构建了基于R参数的最大波幅预测模型,选取4个涌浪案例验证了模型的可靠性。研究结果对探究深水与浅水区滑坡涌浪的预测具有参考意义。

The submergence ratio of landslide is an important factor that affects the generation and propagation of landslide-generated surge wave.The effects of slide scale,sliding velocity,and water depth on surge wave properties are investigated via indoor physical modelling of a granular landslide based on orthogonal test.The research findings are presented as follows:(1)In the case of entire submergence of landslide body,the head wave is featured with large amplitude,gentle wave fronts and steep wave rears and a symmetrical wave profile both to the vertical and the horizontal axes,propagating in a “creeping” state.In the case of partial submergence of the sliding body,the surge waves feature obvious head wave crests,sharp initial form,a symmetrical wave profile to the vertical axis,and no obvious valley.(2)A method of classifying wave type is proposed based on the relationship between unit-width volume ratio R and Froude number Fr.The types of landslide-generated waves are divided into stokes-like waves,cnoidal-or solitary-like waves,and bore-like waves.The dividing equations are defined.(3)A predictive model for maximum wave amplitude is obtained in consideration of parameter R.Four cases of landslide surge are taken to verify the reliability of the model,and the calculated results are found to be in good agreement with experimental data.The research findings are of referential value for predicting the landslide-generated wave in both deep water and shallow water.

滑坡涌浪是库区最常见的自然灾害之一,为了对库区滑坡涌浪的灾害范围进行更加准确、高效的模拟,基于Sassa滑坡运动模型、COMCOT海啸模型及其开源有限差分程序、流体力学建立了流动性滑坡涌浪动力学模型。为了使模型能更好地反映滑坡涌浪的实际运动,模型考虑了滑坡涌浪的强烈耦合作用力、波浪破碎等因素对滑坡涌浪运动的影响,并通过龚家方滑坡涌浪案例验证了模型的有效性。模拟结果表明:①模拟得到滑坡的运动过程、堆积体形态、涌浪的产生、传播、爬坡与野外观测情况基本吻合;②由于岸边波能集聚,涌浪的岸边爬坡波高比河道内的波高更高;③爬坡波高在沿程递减的同时也存在波动,这与观测点的具体地形条件有关。由于模拟结果与野外观测情况相符,因此可将该模型应用于类流体滑坡涌浪的模拟,该模型的模拟结果可为类流体滑坡涌浪灾害防治工作提供参考依据。

Landslide surge is one of the most common natural disasters in reservoir area. In order to simulate the disaster range of landslide surge more accurately and efficiently, we established a dynamic model of landslide surge based on SASSA landslide motion model, COMCOT tsunami model and its open source finite difference program. The model considers the strong coupling force of landslide surge, the wave breaking and other factors that affect the movement of landslide surge to better reflect the actual movement of landslide surge. The validity of the model is verified by the case study of the landslide surge in Gongjiafang. The simulation results show that: 1) the movement process of landslide, the shape of accumulation, the generation, propagation and climbing of the surge obtained from the simulation are in good agreement with field monitoring; 2) the wave height of the surge on the bank is higher than that in the river due to the wave energy accumulation on the bank; 3) the wave height on slope decreases and fluctuates along the way, which is dependent on the specific topography of monitoring point. Because the simulation results are consistent with the field observation, the model can be applied to the simulate the surge of fluid-like landslide.The simulation results of the model can provide a reference for the prevention and control of the surge disaster of fluid like landslide.

This paper presents a multi-fluid Navier-Stokes modeling of the waves generated by two granular slides (subaerial and submarine) which were previously studied experimentally and a pure synthetic submarine case used for results interpretation. In the numerical model, air and water are considered Newtonian fluids. The slide is modeled as a Newtonian fluid whose viscosity is adjusted to fit the experimental results. Once the viscosity is adjusted, the first and the second waves are shown to be accurately reproduced by the model even though the computed slide is slower. For the subaerial case, the viscosity value found is shown to be consistent with the granular mu(I) rheological law. The second part of this work focuses on the energy transfers between a slide and its generated waves. Energy balance is computed in each phase. The wave energy is evaluated in the wave propagation zone. Energy dissipation, kinematic and potential energies are taken into account in the computation of energy transfer ratio allowing for a better understanding of the phenomena. In light of these results, the wave train generation process is discussed as well as the importance of the slide dynamics in the wave generation stage. The amount of energy transferred to wave is not constant with time and the transfer rate depends strongly on the definition of this rate as well as the case considered. For instance, in the subaerial case simulated, the energy transferred to surface waves is 30% of the energy transferred to water at the time the transfer stops, but this conversion rate is only equal to 4% of the overall available potential slide energy at the end of the process. For the two submarine cases simulated, the corresponding values, equal in both cases, are 2% and 1%, respectively. The simulation results also show that the slide energy is transferred to the water in a short period of time at the beginning whatever the case considered. This observation may be related to the initial nil slide velocity (subaerial case) and the relatively large slope values considered (both cases). Nevertheless, the results illustrate the importance of accurate simulation of the slide dynamics within the wave generation process.

库岸滑坡是一种常见地质灾害,如果无法及时预测而出现下滑,则滑坡入库后很可能诱发涌浪,危及河道交通或附近水利设施安全。以弯曲型河道滑坡入库诱发涌浪为研究对象,基于Flow-3D模拟弯曲河道型库岸滑坡涌浪传播过程及其与下游水利设施——大坝相互作用。为了检验水工物理模型试验的有效性和精度,在相关库岸滑坡涌浪研究基础上构建了三维滑坡涌浪数值模型。研究表明:三维数值模拟和水工物理模型试验结果吻合较好,主要体现在涌浪水面高度变化和传播过程。同时,分析不同水深和下滑坡角条件下大坝和滑坡涌浪相互作用过程,得出最危险的水深条件和入射角度,通过工程实例验证分析得出最大动水头小于涌浪高度水头且沿水深有一定程度的折减,则采用最大涌浪爬高水位静力方法计算分析坝体应力,其结果偏安全。

As a common geological hazard,reservoir bank landslide would most probably induce surge waves in river if not prewarned in time,endangering river traffic or the safety of nearby water conservancy facilities.The propagation of surge wave induced by the landslide of curved river bank in reservoir and its interaction with downstream dam were simulated by using Flow-3D.A three-dimensional landslide surge model was constructed to verify the validity and accuracy of hydraulic physical model test.The result of the three-dimensional numerical simulation was in good agreement with that of hydraulic physical model test in terms of the water surface height change and the propagation process of the surge.In the mean time,the most dangerous water depth and incident angle conditions were obtained by analyzing the interaction between the dam and the landslide surge under different conditions.Engineering examples demonstrated that the maximum dynamic water head was smaller than the water head of surge height,and reduced along the water depth direction.In such cases,the stress of the dam calculated according to the static maximum water head of the surge is safe.