Experimental study of two saturated natural soils and their saturated remoulded soils under three consolidated undrained stress paths

Abstract

In this paper, an experimental investigation is conducted to study the mechanical behavior of saturated natural loess, saturated natural filling in ground fissure and their corresponding saturated remoulded soils under three consolidated undrained triaxial stress tests, namely, conventional triaxial compression test (CTC), triaxial compression test (TC) and reduced triaxial compression test (RTC). The test results show that stress-strain relation, i.e. strain-softening or strain-hardening, is remarkably influenced by the structure, void ratio, stress path and confining pressure. Natural structure, high void ratio, TC stress path, RTC stress path and low confining pressures are favorable factors leading to strain-softening. Excess pore pressure during shearing is significantly affected by stress path. The tested soils are different from loose sand on character of strain-softening and are different from common clay on excess pore water pressure behavior. The critical states in p′– q space in CTC, TC and RTC tests almost lie on one line, which indicates that the critical state is independent of the above stress paths. As for remoulded loess or remoulded filling, the critical state line (CSL) and isotropic consolidation line (ICL) in e-log p′ space are almost straight, while for natural loess or natural filling, in e-log p′ space there is a turning point on the CSL, which is similar to the ICL.

Keywords

stress paths / static liquefaction / natural soil / remoulded soil / loess / structure / total strength indices / excess pore pressure

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Acknowledgements

The authors would like to express their gratitude to Mr. Wang Xinxin and Mr. Tang Fuyuan for their assistance in the tests, Mr. Wu Xiaofeng for his suggestion in the tests and Dr. Zhou Feng, Dr. Liu Fang, Mr. Shen Zhifu, Mr. Su Jiaxing for their help in the process of preparing this paper. This research was financially supported by China National Funds for Distinguished Young Scientists (Grant No. 51025932), the National Natural Science Foundation of China (Grant No. 10922158 and No. 40534021), and the Land and Natural Resources of China (Grant No. 1212010914013). These supports are greatly appreciated.

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2014 Higher Education Press and Springer-Verlag Berlin Heidelberg