Earthquake Induced Ground Motion Mitigation Using Geotextile Encased Infill Material System

Occurrence of earthquakes creates combination of horizontal and vertical ground motions. When these ground motions interact with saturated or partially saturated soils, soil liquefaction occurs. To mitigate the effects of ground motions, there are conventional isolation systems available for isolating and improving the performance of foundation structure. However, assessment of these isolation barrier systems in liquefiable soils was limited. In the present research, an attempt was made to develop an effective and economical barrier model for mitigating ground motions induced by an earthquake. The barrier system was installed in a liquefiable deposit to evaluate both isolation and liquefaction resistance characteristics. For developing barrier system, commercially available polyurethane (PU) foam which is known for its absorption characteristics was used. The experiments were performed on saturated ground model having 40 and 60% relative density and they were tested under repeated shaking conditions with and without barrier reinforcement. Experimental results showed that the developed PU foam isolation barrier system placed inside liquefiable soil performs well in mitigating earthquake borne ground motions, improves seismic resistance of soil and minimizing settlement compared to unreinforced ground bed.