Liquefaction Screening—Non-plastic Silty Sands and Sands

Abstract

Liquefaction screening of sands and silty sands using cone penetration resistance is a difficult problem. The presence of silt particles among the sand grains in non-plastic silty soils alter the intergrain contact density and affect cyclic resistance, flow and consolidation characteristics, and cone resistance of the soil. Intergranular void ratio concept is briefly summarized. Based on this concept, the effects of silt content on intergrain contact density and the relationship between intergrain contact density and cyclic resistance ratio (CRR) is highlighted using experimental data. Effect of silt content on permeability k and coefficient of consolidation cv is also presented. Model cone tests are used to quantify and highlight the influence of intergrain contact density and coefficient of consolidation on normalized cone resistance qc1N. A possible rational interrelationship between qc1N, CRR, and T where T = vd/cv, v = cone penetration velocity, and d = cone diameter is presented and compared with current liquefaction screening charts based on CRR-qc1N-FC, where FC is the percent silt content. With further research, a rational CRR-qc1N-T based liquefaction screening method appears likely.