Evaluation of Soil Improvement Via Blasting Using Array‐Based Surface Wave Tests

Abstract

The goal of soil improvement via blasting is to densify loose sand layers through the rearrangement of soil particles. To effectively achieve this goal, the sand must be clean, loose, and saturated. Because the effectiveness of soil improvement via blasting is dependent on these conditions, it must be evaluated by in‐situ or laboratory tests. Array‐based surface wave tests are well suited to evaluate the effectiveness of blasting‐based soil improvement due to their capability of mode separation in dispersion curves and their non‐destructive characteristics that allow tests to be performed relatively economically and quickly without additional soil disturbance. In this study, a series of array‐based surface wave tests at different sequential times following a blasting event have been performed to evaluate the effectiveness of the soil improvement with time at a landfill site in South Carolina. Surface wave dispersion curves and shear wave velocity profiles from the tests successfully captured the abrupt stiffness decrease due to blasting‐induced liquefaction and the subsequent gradual increase in stiffness due to densification, the development of cementation, and the dissipation of blasting‐induced excess pore water and gas pressure with time. The test results demonstrated that array‐based surface wave tests performed at various times following a blasting are an effective means to evaluate the effectiveness of blasting soil improvement.