Time-dependent small strain properties of a lime-treated lean clay

Abstract

This paper evaluates the time-dependent small strain properties of a lime-treated red mudstone fill material (LRMF) during long-term curing up to 8640 hours. The main objective is to develop a unified framework describing the S-shape evolution mode of small strain shear modulus $G_{\max }$ and Poisson’s ratio $v$. With this emphasis, a series of bender-extender element tests was conducted on LRMF compacted at three void ratios and two lime contents. Three-stages, namely, stage I (initial curing), stage II (primary curing) and stage III (secondary curing) were clearly clarified. Such a pattern was captured well by the small strain properties characteristic curve (SSPCC). The separations between each stage were reasonably determined by examining the inflection point and the tangent at the inflection point. The feasibility of the proposed framework was verified by applying SSPCC to not only RMF, but also to a wide range of artificial soils including lime-treated silt and cemented clay. Microfabric modification was found responsible for the three-stage behavior of small strain properties. Compared to the untreated specimen, the lime hydration causes an evident pore volume transition where the noticeable increase in $G_{\max }$ is observed even at short curing period. This transition proceeds at stage II, leading to the densification in soil fabrics and the progressive growth in $G_{\max }$. Further curing period denotes the slowdown of the pore structure change and the agglomeration, from which the stage III can be determined.