Estimation of Landslide Impact Disaster by Discrete Element Method: Jiangping Hydropower Station, Hubei, China

An evaluation model of landslide risk is established with PFC in order to study the impact effect of landslide on existing buildings in Jiangping hydropower station, Hubei, China. The corresponding numerical parameters of parallel bonding are obtained during the calibration step, in which some biaxial compression tests are carried out. The conversions of energies among body force work, kinetic energy, strain energy, friction work and bond energy during the process of landslide motion are discussed based on the law of conservation of energy. Then the relationships among the impact energy, the geotechnical strength parameters and the outrun distance of landslide are studied. The results show that the calculated impact energy gotten from the proposed landslide model is far less than that gained from the rigid body model. The calculation of the proposed method is on the safe side. The total energy carried by the landslide is originated from the loss of potential energy. The calculated impact force has a less effect on the buildings because the dissipation of the friction energy caused by medium disintegration is neglected in the later. The weaker the degree of the medium cementation is, the greater the proportion of the friction energy dissipation is, and the smaller the corresponding proportion of landslide impact energy is. The landslide impact energy has a linear relation with the bond force between particles, and the maximum landslide impact energy decreases exponentially with the increase of the landslide horizontal movement distance. The simulation also shows that the ratio of the impact energy accounting for the total loss of potential energy in the proposed weak bond model is more than about two times of the sledge model, as well as more than about three times of the strong bond model. The proposed model is closer to the actual landslide motion process, so it has great promise in estimating the hazard of landslide on buildings.