Study on Sliding Block Method and its Application on Caisson Type Quay walls

• Main Authors: Gwo-Shyang Hwang, 黃國祥
• Other Authors: Cheng-Hsing Chen
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/90833814666627921861

博士 === 國立臺灣大學 === 土木工程學研究所 === 90 === Based on the Newmark’s (1965) sliding block model, the sliding displacement of a rigid block during an earthquake can be calculated and used for seismic design of retaining structures. The purpose of this thesis is to investigate the characteristics of sliding response curve obtained from sliding block method and its application on the cases of caisson type quay walls that had been suffered large lateral displacements during earthquakes. In this study, it has been shown that the sliding response curve is a continuous curve with negative slope and positive curvature. In order to normalize the sliding response curve, a new normalizing factor has been derived considering the numbers of sliding, the duration of positive relative acceleration, the degree of fullness and the predominant period of ground acceleration time history. For illustration, 40 earthquake records were selected and analyzed. Results show that the value of the proposed normalizing factor correlates well with the sliding displacement at N/(A+)=5%. Besides, the sliding response curves of Chi-Chi earthquake (1999) were analyzed to show the characteristics of sliding response curve for different ground conditions. To study the behavior of caisson type quay walls that had experienced large lateral displacement during earthquakes, 3 cases were thoroughly investigated. They are: the P-3 section of Port Island in Japan (Kobe earthquake, 1995), the #2 pier of Taichung Harbor in Taiwan (Chi-Chi earthquake, 1999) and a shaking table test (Ghalandarzadeh et al., 1998). According to their characteristics of ground failure, a simple model with an extended volume of backfill soil mass is proposed to simulate the mechanism of large lateral displacements of caisson type quay walls occurred during earthquakes. Results show that the non-dimensional parameters corresponding to the proposed simple model are similar for in-situ cases. Finally, the method of finite element is used to analyze the 3 cases. The results show that the main cause of large lateral displacement occurred is owing to the plastic shearing deformation of foundation soil for each case studied.