Stability of Reinforced Soil Quay Wall Subjected to Combined Action of Earthquake and Tsunami

Abstract

Reinforced soil quay walls are used as shore protection systems. Generally, horizontal layers of geogrids are provided as reinforcement in the backfill soil of the quay wall. These structures are internally stabilized by mobilized tensile strength of reinforcements. A quay wall can be subjected to tsunami load and earthquake load simultaneously. This condition occurs when an earthquake aftershock reaches the quay wall structure at the same time of a tsunami impact. Therefore, a combined analysis of quay walls subjected to earthquake and tsunami at the same time is necessary. In this study, horizontal slice method is used to evaluate the stability of the reinforced soil quay wall subjected to earthquake and tsunami. The failure surface is generated by optimizing the angle of failure plane of each slice, so that the mobilized tensile force on the reinforcement is maximum. Thus, the generated failure surface could justify the actual failure surface. It was observed that normalized force acting on the reinforcement is considerably increased under the combined effect of earthquake and tsunami. Stability of the wall is evaluated by varying several parameters, such as acceleration coefficient of earthquake motion, internal friction angle of soil, inclination and height of the quay wall, height of seawater level and height of tsunami waves, to find out the effect of these parameters on normalized reinforcement strength.