Experimental study on relationship between critical state line and zero creep volume change zone in engineered silty sand

Abstract

Volume change during creep is one of the important factors to explain various time-dependent problems such as the pile set-up effect. Park [1] and Park et al. [2] experimentally measured creep volume characteristics under various stress conditions using engineered silty sand obtained from weathered granite soil in Korea. They found that a zero-creep volume change zone (ZCVZ) exists on the e-log p’ plane. If the void ratios at the beginning of the creep are above the ZCVZ on the e-log p’ plane, the volume decreases during creep; if they are below the ZCVZ, the volume increases during creep. In this study, a series of simple critical state (CS) tests which can simply determine the critical state parameters in sandy soils were performed to estimate the critical state line (CSL) and compared with ZCVZ. In addition, the CSL obtained using the method proposed by Santamarina and Cho [3] was compared with those obtained by the triaxial test. The CSL for Jumunjin sand and engineered silty sand is close to ZCVZ. Therefore, the CSL can be used as a reference line to determine the volume change pattern by creep.