Time Domain Wave Equation Analysis for Axially Loaded Group Piles

• Main Authors: Chih-Hsiang Liu, 劉祉祥
• Other Authors: Der-Wen Chang
• Format: Others
• Language: zh-TW
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/29918844716188404387

碩士 === 淡江大學 === 土木工程學系 === 87 === This study establishes the wave equation analytical model for piled raft foundation which is subjected to a vertical exciting force. In order to simplify the analysis, this study takes the group-pile as a single equivalent pier, and the corresponding wave equation is derived with the FD method. Soil spring constants and damping coefficients were founded by theoretic t-z and Q-z equations and a time dependent radiation damping model derived from Novak''s dynamic impedance functions (1974). Moreover, this study refers to the research of interactive single pile model, and estimates the response of the pile foundation with the cap. From this study, following results were observed for piled raft foundation response: 1. The piled raft foundation response amplitude becomes smaller as the pile-soil stiffness contrast decreases. 2. The response amplitude decreases with the increase of the ratio of pile spacing and pile diameter. 3. There is less influence on the pile raft foundation response by variating the pile slenderness ratio. 4. Similar results were obtainable from the equivalent pier model and the interactive single pile model while the former yields more conservative solutions. The piled raft foundation response under the dynamic axially loads has been analyzed in this study. A more complete approach including the lateral loaded response needs to be further investigated.