Study on the calculation method of water inflow velocity of loose rock landslide

Based on rock structure mechanics and water sediment dynamics, considering the additional resistance caused by the interference of loose landslide particles on the flow structure, this paper deduces the resistance calculation formula of loose rock landslide particles when entering the water. It modifies the landslide velocity formula (ASCE) recommended by the American Society of Civil Engineers. The acceleration calculation formula and velocity calculation formula of bulk rock landslide entering water are obtained, and the determination method of main parameters in the formula is given. Based on the physical model test data of a three-dimensional loose rock landslide and the example data of the Xintan Landslide in the Yangtze River, the rationality of the calculation results of this formula and the ASCE formula is compared and analyzed. It shows that the ASCE formula calculates the average velocity of landslide movement on land, and there will be a noticeable deviation from the actual situation when it is used to calculate the water entry velocity of a loose rock landslide. The formula given in this paper is more practical and can be used to calculate the velocity of loose rock landslide entering the water.