Abstract:
Liquefaction-induced lateral spreading is a common phenomenon after strong seismic events. Typically lateral spreading occurs in sloping ground close to waterways in regions with liquefiable underlying soils and may result in significant damage and lead to significant replacement expense of existing buildings and structures. The installation of stone columns may be used to reduce liquefaction potential for foundations in level ground but there is little literature on stone columns being used to mitigate liquefaction-induced lateral spreading. This study aims to evaluate the effectiveness of stone columns to mitigate liquefaction-induced lateral spreading. A case study from the recent 22 February 2011 Christchurch Earthquake was used as a basis of the study and the study was carried out y numerical analyses. Current state-of-the-art design procedures for stone columns to prevent liquefaction have been used to assess its applicability to mitigate lateral spreading. The main improvement mechanisms of stone columns – densification, drainage and reinforcement and the lateral extent of the improvement zone have been investigated. Generally, stone columns remediation was found to be effective in reducing the lateral displacement that was caused by liquefaction due to the seismic event. However, complementary ground improvement measures may be required to eliminate lateral displacement at the crest of the waterway. Overall, the study highlights the potential of using stone columns as a countermeasure against lateral spreading and provides a basis on the development of design procedures for stone columns as a countermeasure against liquefaction-induced lateral spreading in the future.