Research On Some Problems In Seismic Analysis Of Gravity Quay Wall

As one of three commonly used wharf structure types, gravity quay wall has been widely used in harbor engineering. Post-earthquake reconnaissance indicates that, once wharf structures fail in earthquakes, wharf will be out of operation, which can results in huge economic loss. Therefore, studies on the displacement calculation method of gravity quay walls in earthquakes are of great significance. Comparing with the advanced displacement-based and performance-based seismic design philosophy in the seismic design of piers in foreign, the force-based seismic design in our country is inadequate. Based on displacement-based and performance-based seismic design philosophy, this study aims to investigate the calculation methods of excessive pore pressure time history, earth pressures of layered soil, the simplified procedure for rotational and sliding displacements of gravity quay wall in earthquakes, the coupling effect between rotation and sliding of the wall, and the dynamic time history analysis of gravity quay wall. The details are listed as follows:1. Based on the stress-based excessive pore water pressure calculation method and the cumulative damage hypothesis, a simplified procedure, which can incorporate the excessive pore water pressure time history, is proposed. The validity of the proposed method is verified by comparing the results of the proposed method with that of other available methods.2. Calculation method for predicting the earth pressure of layered soil under the assumption of curved failure surface is proposed. Comparisons between the predicted and experimental results verify the accuracy of the method proposed in this paper. Effects of ground motion and soil parameters on earth pressure are investigated using the proposed method.3. The proposed earth pressure calculation method is optimized with multiple order curved failure surface to obtain a simple and effective optimization method of failure surface. Results predicted with the optimized method and that with the method based on the rupture angle of each micro-element are compared. Comparison results indicate the validity of the optimized method.4. A new method to determine the displacement of gravity quay wall with saturated backfill soil under earthquake loading is developed based on the calculation methods of excessive pore pressure time history and earth pressures proposed in this paper. Comparisons between the results predicted with the proposed method and that with previous studies verify the accuracy of the proposed method. A parametric study is conducted to study the effects of ground motion and soil parameters on the displacement of gravity quay wall; and the coupling effect between rotational and sliding displacements of the wall is analyzed using the proposed method.5. Time history analysis of gravity wharf in earthquakes is conducted. Pore water pressure after pier foundation and backfill, as well as the displacement of gravity wharf, are studied.