studied the solid-liquid mixture composed of rubble, sand, clay, and water. However, some scholars have studied the mixture of solid-liquid debris flow. studied the impact performance of dry sand and viscous fluid by the conducting centrifugal test. For example, Ashwood and Hungr used quartz sand and rubble for performing the physical simulation test to study the impact of debris flow. ĭebris flow study is relatively complex, and previous studies are generally simplified into pure particle matter and fluid. The data show that debris flow composed of particles and fluids has great kinetic energy and impulsive force and can cause devastating damage to the structure.

In China, there have been many major debris flow disasters, among which, the most notable one is the August 8 Zhouqu debris flow disaster in Gansu Province, with the severe consequences of 1,481 deaths, 1,824 injuries, 284 missing persons, and nearly 20,000 people affected. The total area of debris flow distribution is 4.3 million km 2, of which 1.3 million km 2 is an intense active area. The Tianshan Mountains, Kunlun Mountains, Himalayas, Qinling Mountains, Hengduan Mountains, and Changbai Mountains in China are all high-risk areas of debris flow. Debris flow disasters are extensively distributed around the world, while China is a mountainous country and the mountainous area accounts for approximately 69% of the total land area. Limited by a certain slope groove, it pours down to the accumulation area at a significantly fast speed, which can cause great damage to a variety of buildings along the way. It is a special fluid-solid coupling material formed by rainfall confluence. Debris flows are characterized by rapid flow velocity, large flow velocity, sudden eruption, and amazing destructive power. It is the result of the combined action of topography, meteorology, hydrology, soil, and vegetation in the basin.

Introductionĭebris flow is a solid-liquid two-phase mixed fluid containing a large number of rubbles and sediments, showing the movement characteristics of viscous laminar flow or dilute turbulent flow. The obtained results have a certain reference value for the study on the impulsive force and dynamic response of the flexible retaining structure impacted by solid-liquid two-phase debris flow and the engineering design of the flexible retaining structure. The debris flow evaluation results of flexible retaining structure impacted by solid-liquid two-phase debris flow are in an order of magnitude with the empirical formula results. The dynamic time-history curve of the coupling numerical analysis method for the flexible retaining structure is consistent with the results of the existing literature. The simulation results show that the coupled SPH-DEM-FEM numerical analysis method can visualise the impact of the solid-liquid two-phase debris flow on the flexible retaining structure, reproducing the impact, retaining, water-stone separation, climbing, silting, and deposition process of debris flow.

Meanwhile, the effectiveness of the coupling numerical simulation is verified.

The numerical results are compared with those of the calculation formula of the peak impulsive force of the semiempirical debris flow. In the present study, the process, impulse force, and dynamic response of a flexible retaining structure subjected to debris flow under different slopes were investigated, respectively. In order to explore the impulsive force and dynamic response of flexible retaining structure impacted by solid-liquid two-phase debris flow, a complex dynamic interaction model of particle-fluid-structure has been established by employing the SPH-DEM-FEM coupling numerical analysis method. Flexible retaining structure is demonstrated to be an effective measure for debris flow prevention in mountainous areas, which can effectively separate water and stone, reduce particle mass, and dissipate kinetic energy.

Impulsive force models