Liquefaction Remediation in Silty Soils Using Dynamic Compaction and Stone Columns
S. Thevanayagam, G.R. Martin, R. Nashed, T. Shenthan, T. Kanagalingam and N. Ecemis
MCEER-06-0009 | August 28, 2006
The objective of this report is to introduce a rational analysis procedure and design guidelines for liquefaction hazards mitigation in saturated sands and non-plastic silty sands using Dynamic Compaction (DC) and Vibro-Stone Columns (SC). A numerical model was developed to simulate the densification processes during both techniques through quantifying pore pressure generation due to vibrations caused by successive impacts on the ground surface or repeated insertions of a vibratory probe into the ground. The effects of site-specific conditions such as hydraulic conductivity, fines content, etc. were quantified for a range of energy contents delivered to the soil at specific spacing. In addition, the effects of field operational parameters such as energy per impact, number of impacts, time cycle between impacts, impact grid spacing, impact grid pattern, and wick drain spacing, in the case of DC, or area replacement ratio and wick drains spacing in the case of SC, on post-improvement resistance to liquefaction were included in the study. Based on the results, design charts and design guidelines for liquefaction mitigation in silty soils using DC and SC are provided. Design procedures and design examples are also provided.