Reliquefaction resistance of Solani sand subjected to repeated excitations using shaking table experiments

Examining the reliquefaction resistance of sand deposits is more challenging due to the complex interplay of several factors that may increase or decrease the resistance. This resulted in severe limitations in understanding the reliquefaction mechanism of sand deposits subjected to repeated shaking events. The present study attempted to overcome this limitation by examining the reliquefaction resistance using 1-g shaking table experiments. A total of 65 shakings were performed on saturated Solani sand with varying acceleration amplitude, dynamic frequency, shaking duration, and relative density of the sand specimen. All the above factors were experimented with three different shaking patterns (incremental, uniform and decremental) and independent events. For each shaking event, generation and dissipation of excess pore pressure, soil subsidence, and relative density variations were presented. The beneficial effect of seismic preshaking were applicable in partially liquefied soils that were subjected to incremental shaking pattern. On the other hand, contrary results were reported for uniform and decremental shaking patterns, where the later found to be more damaging. The state of the soil (partially or completely liquefied) governs the reliquefaction resistance, as the beneficial effect of preshaking was applicable only in partially liquefied soils, irrespective of the shaking pattern. Whereas complete liquefaction disturbs the structure of existing sand specimens and results in reduced reliquefaction resistance for future seismic events.