e–log σ_v′ relationship for marine clays considering initial water content to evaluate soil structure

ABSTRACT

Using the data of conventional consolidation tests, the linear ln v–ln relation (v = 1 + e is a specific volume) was determined in the region of large effective stresses, and was named as high water content compression line (HWCL). A unique relation between normalized ln v−ln was obtained for twenty-one clays with narrow band. Based on the normalized HWCL, e–log relation of normally consolidated clay with a specified initial water content was proposed. In this model, the beginning part shows a linear e–log relation in the range of <σ′_HWCL and, in the latter part of the range of ≥σ′_HWCL, e–log relation is on the HWCL, where σ′_HWCL is the converging pressure to HWCL. It was shown that the empirical C_c–w_L relations could be explained using the HWCL based model with the consideration of initial water contents. By using the proposed model, the change of compression properties of marine clay due to soil structure formed in the deposition process was shown schematically, and the effects of soil structure of in situ marine deposits were evaluated, considering the effect of initial water content.

KEYWORDS:

• Clay
• compression
• consolidation
• disturbance
• e-log σ_v′ curve
• liquid limit
• specific volume
• structure
• water content

Acknowledgements

The consolidation tests for Singapore Port clay, Bangkok clay, Drammen clay, Bothkennar clay, and Louiseville clay were performed at the Soil Mechanics Laboratory of the Port and Airport Research Institute (PARI). The data for Banjarmasin clay were provided by the Toa Corporation. The author wishes to expresses sincere gratitude to Prof. Tanaka, Hiroyuki of Hokkaido University, Dr. Watabe, Yoichi and Dr. Tanaka, Masanori of PARI, and the late Dr. Hanzawa of Toa Corporation for their assistance and encouragement.