Zhang, Yu, 2009, Impact of freeze-thaw on liquefaction potential and dynamic properties of Mabel Creek silt: University of Alaska Fairbanks, Ph.D. dissertation, xxii, 191 p.
In early winter 2002 (November), the Alaska Denali earthquake (Mw=7.9) caused significant damage in partially frozen fine-grained soil, and extensive liquefaction was observed in glacial fine-grained saturated soil surface deposits near Tok, Alaska. It illustrated that there was a need to evaluate the seismic response and liquefaction potential of fine-grained soil in cold regions; however, until now most of the research on the liquefaction phenomenon and seismic response were mainly about soil in non-cold regions. The seismic response and liquefaction potential of soils in cold regions, especially those of fine-grained nature, has not been studied thoroughly and therefore is not well understood. This document presents a laboratory study on liquefaction potential and cyclic response of fine-grained soil in cold regions. As the main features of the soil in the ground of cold regions, temperature change at below freezing temperatures or near-freezing temperatures, and the seasonal climate change were evaluated on liquefaction potential, dynamic properties, and post-cyclic-loading settlement of fine-grained soils. Increasing temperatures from near freezing to completely thawed temperatures (i.e., 24 degrees C, 5 degrees C, 1 degree C, and 0.5 degree C) were used to thaw the frozen Mabel Creek silt to simulate temperature change on it, or the Mabel Creek silt experienced several freezing and thawing alternating processes (i.e., 1, 2, and 4 freeze-thaw cycles) to simulate seasonal climate change. Triaxial strain-controlled cyclic tests were conducted to evaluate liquefaction potential, dynamic properties, and post-cyclic-loading settlement. Based on this limited laboratory effort, results show that in most cases, temperature rise and freeze-thaw cycles can impact: (a) liquefaction potential, (b) dynamic properties, and (c) post-cyclic-loading settlement of fine-grained soils. However, there was one case exception: When a fine-grained soil was conditioned in a partially frozen state, the possibility and threat of liquefaction significantly increased.
Theses and Dissertations
