Liquefaction mitigation of desert sand using rapid impact compaction

Abstract

Rapid impact compaction (RIC) is a ground improvement system that, lately, has been widely used as a soil modifier to strength and deformability characteristics. This paper studies the efficiency of this method to mitigate liquefaction susceptibility of shallow to middle-deep desert sand deposits during the strong event. The study was carried out by direct field measurements using cone penetration tests (CPTs) in the vicinity of a project site in Dubai, UAE. CPTs were carried out before and after using the RIC technique as a remedial measure. The project area was compacted using the RIC method to reduce liquefaction vulnerability of the area. Liquefaction susceptibility of the project site was evaluated prior and after the improvement using two assessment methods. A comparative study of the area, before and after remediation, showed that the RIC method is an efficient way to mitigate liquefaction risk. The factor of safety against liquefaction was significantly improved down to a depth of 3–4 m below the groundwater table (4–5 m below the ground surface). The factor of safety against liquefaction was enhanced by (1.2–to 7) times the factor of safety before the treatment as indicated by the two methods used for liquefaction analysis. The liquefaction study was performed based on a maximum possible earthquake magnitude of M = 7.5 and peak ground acceleration of 0.25 g.