CPT-Based Evaluation of Blast Densification (BD) Performance in Loose Deposits with Settlement and Resistance Considerations

Among various methods for modification and treatment of saturated loose deposits, blast densification (BD) or explosive compaction is known as an efficient deep soil improvement method. Due to no depth restrictions, simplicity, and inexpensive equipment through controllable environmental effects, BD has more advantages than other approaches for loose deposits compaction. In this paper, 14 different BD projects from USA, Canada, France, Poland, Nigeria, Russia, Belgium, and India have been compiled and studied. Owing to existence of saturated loose deposit layers in various depth and liquefaction hazard, BD was employed for treatment, and CPT records were utilized for site investigation and performance evaluation. The consequences of BD include increased relative density in all sites and volume changes approximately about 2–10 % in loose deposit layers. Analysis on the compiled database focuses on the role of powder factor in induced settlement due to explosion. In addition, observations indicate that after blasting, cone tip resistance (qc) doubled in a few sites, and qc increased considerably for most of the cases. Therefore, BD implementation resulted in improvement of strength parameters and significant reduction of liquefaction hazard.

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