CPT-based liquefaction resistance of clean and silty sands: a drainage conditions based approach

Abstract

The cone penetration test-based simpli ed liquefaction triggering evaluations are largely based on linking liquefaction manifestations in the eld to cone penetration resistance. These relationships are interpreted in such a way that for given penetration resistance, the liquefaction resistance increases as non-plastic nes content (FC) increases. However, several studies have indicated discrepancies in this relationship.Hence, there is a lag in rational scienti c understanding of this observation. In this study, an experimental research program was undertaken to investigate the CPT-based liquefaction assessment by considering the effects of drainage conditions on the relationship between CPT resistance and liquefaction resistance. First, clean sand and silty sands having 5, 15, and 35% FC were tested at different relative densities by stress-controlled cyclic direct simple shear (CDSS) tests to investigate cyclic resistance of silty sand with varying amounts of non-plastic nes. Then, a set of tests involving piezocone penetration (CPTu), seismic CPTu (SCPTu), and direct push permeability (DPPT) were undertaken in a large-scale box lled with the same soils used in the CDSS tests. The large-scale test results quanti ed the effect of drainage conditions (coe cient of consolidation) on cone penetration resistance. Finally, by combining the CDSS and CPTu test results, an alternative CPT-based liquefaction resistance relationship was proposed by considering the effects of drainage conditions.

Applicability of soil‐type index for shear wave velocity‐based liquefaction assessment

“…Although the available experimental data incorporating both controlled in‐situ and laboratory tests at the q c1N range in this study (< 50) is quite limited in the literature, there is a general trend that as FC increases from 0% to 15%, there is a noticeable increase in (CRR) 7.5 at a given q c1N . For the sand with 35% FC, a sharp increase is observed in CRR 7.5 with increasing q c1N (e.g., 25,61 ). Hence, the boundary curve of this range (I c = 1.3) was generated by considering the similar trend for the other two I c ranges (1.57 < I c ≤ 1.95, and 1.95 < I c ≤ 2.9).…”