NUMERICAL STUDY OF EARTH PRESSURE ACTING ON SEMI-UNDERGROUND STRUCTURES DURING AND AFTER EARTHQUAKES

Semi-underground structures are often constructed for storing water. Most parts of their bodies are placed underground and the roofs are covered with thin or no soil layers. The current earthquake design standard for semi-underground structures mainly considers the earth pressure, which is proportional to ground acceleration and displacement. Detailed mechanisms of active and passive earth pressures are not considered in the current design method. In this paper, we study the dynamic interaction mechanism between ground and side wall of semi-underground structures during earthquakes based on FEM analysis. Earth pressures during and after the earthquake, which result from shear-failures in the surrounding soil, are especially examined. The results show that effects of soil failure enlarge the earth pressure. Passive earth pressure only acts on the shallow part of the wall, whereas active earth pressure acts on the deeper part as well, during earthquake. The residual earth pressure acts after earthquake, which is intermediate between the maximum and minimum values during earthquake.