Groundwater affects the load carrying behavior of foundations as the effective stress changes with the location of groundwater level (GWL) where the non-linear variations in stiffness and strength and the GWL influence zones below the foundation are involved. In this study, the load-settlement curve and the axial load capacity of piled-raft foundation with changes in GWL was investigated based on the results obtained from the finite element (FE) analyses. The full depth range of GWL from the top soil surface to the depth of well-below pile base was considered in the FE analyses. Changes in the effective stress and state-dependent soil stiffness with GWL were quantitatively evaluated and considered. It was found that the axial load capacity changed most significantly for GWL depths from 0 to 1.0 times the raft width, indicating that the GWL influence depth for piled rafts is controlled by raft size. The GWL effect factors for the load capacity (Cw) and settlement (Sw) of piled rafts were proposed. It was found that the values of Sw were larger than for unpiled rafts. The maximum value of Sw for piled rafts was 1.55 for GWL at the top surface, which decreased logarithmically with increases in the depth of GWL. The correlation of Sw to GWL was proposed.
Bibliographical noteFunding Information:
The study was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) and the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the Ministry of Trade, Industry & Energy (MOTIE), with grants funded by the government of Korea (No. 2016R1D1A1A09919098 and No. 20194030202460).
© 2019, Korean Society of Civil Engineers.
All Science Journal Classification (ASJC) codes
- Civil and Structural Engineering