The purpose of this study is to clarify the dynamic behavior of spillway on soil subjected to cyclic simple shear, which modeled earthquake vibration. In this study, the 2-dimensional discrete element method (DEM) was used. This demonstrated that the soil elements concentrated beneath the inclined spillway were subjected to rotational moment and the spillway was uplifted.
Large earthquakes have often occurred in Japan. The 1995 Hyogo Nanbu earthquake is one of these, where a lot of agricultural lands and facilities were seriously damaged. Especially, the amount of damage to small earth dams composed approximately three-quarters of the whole. According to previous investigations, the damage to small earth dams occurred because of the failure of the spillways on their embankments. In general, spillways are of rectangular shape and made by reinforced concrete. On the other hand, the embankments themselves are soil structures. Therefore, in large earthquakes, the spillways detached from the embankments or failed in the joint of the bottom plate and sidewall due to inertia forces. Fig. 1 shows the damage of the detachment of the concrete type spillway of the embankment. In order to prevent damage to the spillway, the understanding of the dynamic behavior of spillway and the proposal of the quakeproof spillway are necessary. Kawabata et al. (2008) conducted shaking table tests on spillway models focusing on weight, stiffness and cross sectional shape. The behavior of rectangular-shaped underground structures subjected to earthquake vibration is discussed. Koseki et al. (1997) performed shaking table tests to evaluate the safety factor against uplift for the underground structures based on the equilibrium of vertical forces acting on the structures. Yuasa et al. (2000) clarified that the uplift of the underground structures was caused by the transmission of pressure from liquefiable soil and preventing the transmission reduced the uplift displacement.
