Load Capacity of stone columns and geosynthetic encased stone columns during and after seismic excitations
Stone columns are often used to enhance the bearing capacity of weak soils. When such sites are in earthquake prone regions, determination of seismic performance of stone columns and geosynthetic encased stone columns (GECs) under seismic excitations are compared by model tests. The seismic excitations are applied on the models by making use of a 10 ton capacity shaking table. The vertical load capacities and vertical stress-strain behavior of model columns were also investigated. It is concluded that the geosynthetic encapsulated stone columns reduced the settlements under sustained load during the seismic excitation phase of the experimental program. GEC also exhibited higherload capacity during the pile load tests.
Main conclusions drawn from the undertaken experimental analysis is listed below:
- GECs have shown a markedly better settlement reduction performance than the conventional stone columns under the action of the seismic excitations
- The geotextile encasement has behaved as expected. The strain amplitude has increased as thw intensity of the impact increased
- The geotextile encasement materialhas bulged horizontally (radially) while contracting vertically at the proximity of the top bulging zone of the GEC.
- Post-daynamic loading settlement performance of the GEC was significantly better to that of the stone column.