Liquefaction-Induced Buckling Failure of Group-Pile Foundation and Countermeasure by Partial Ground Improvement

Abstract

Pile foundations may lose their lateral resistance in earthquake-induced liquefaction and may fail not only by bending and shear forces but also buckling. Although research has been done on the buckling of pile foundations, it is still necessary to investigate further the buckling of pile foundations during an earthquake and a corresponding efficient countermeasure. Some existing pile foundations may not meet the requirement of present seismic design standards and are vulnerable to buckling failure. In the present study, numerical analyses and model tests were conducted. The validity of the proposed numerical method was first verified through a 1-g shaking table test. Then, the buckling risk of a group-pile foundation and its strengthening with partial ground improvement (PGI) were carefully estimated. Meanwhile, the effectiveness of the proposed countermeasure with PGI against the buckling of the group-pile foundation was confirmed by a static model test. The purpose of the study was to investigate the effectiveness of ground improvement for the retrofitting of vulnerable pile foundations against buckling due to seismic loading.