Seismic bearing capacity of strip footing above an unsupported circular tunnel in undrained clay

摘要

By applying the lower bound theorem of limit analysis in conjunction with finite element, the bearing capacity of a strip footing located above an unlined long circular tunnel in undrained clay is computed with the inclusion of pseudo-static horizontal seismic body forces. The effects of varying the tunnel diameter and the embedment depth of tunnel below the ground level on the seismic bearing capacity of foundation are studied in detail. The design charts are provided for a wide range of pseudo-static earthquake forces. It is expected that the charts provided in this note will be quite helpful for the practicing engineers. Failure patterns are also studied in detail to understand the extent and the type of failure zone which may generate during the collapse.