Influence on Pore Water Pressure Due to Millisecond-Delayed Blast in Blast-Induced Liquefaction

Given the rising prevalence of subsurface blasting projects in urban environments, the significance of research on blast-induced liquefaction has become essential. Controlled detonations in liquefiable soil cause a rapid rise in pore water pressure due to the compression waves generated by the explosion. As the pore water pressure increases, the effective stress of soil get decreases which causes loss of shear strength of soil. Once effective strength is completely lost, even minor shear stress can cause significant soil deformation, mimicking liquid behavior and potentially leading to slope and foundation failures, among other structural issues. An increase in pore water pressure is mainly dependent on scaled distance, the weight of the explosive, and the explosion mode, i.e., simultaneous or delayed. Experimental observations indicate that pore pressure generated by the delayed blast is significantly different from the delayed blast. A model is prepared to replicate the actual test site which has liquefiable soil, using FLAC3D; the effect of delay of blast has been observed, and a validation was conducted for reliability by comparing experimental and numerical models. This study gives a comparison of the delayed blast and the simultaneous blast. Demonstrated results represent that the delay in blast plays a crucial role in increasing the pore water pressure of the soil. Observations further show variations in pore pressure at different distances from the explosion, highlighting the critical role of blast timing in subsurface blasting projects.