Experimental Study on Strength Characteristics of Artificial Structured Frozen Loess

 

Yaling Choua,b,c,*, Chen Xingqianga,b, Jiang Xianganga,b

a. Key Laboratory of Disaster Prevention and Mitigation in Civil Engineering of Gansu Province, Lanzhou University of Technology, Lanzhou 730050
b. Northwest Center for Disaster Mitigation in Civil Engineering of Ministry of Education, Lanzhou, 730050;c. State key Laboratory of Frozen Soil Engineering, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China
* Corresponding author; e-mail: chouyaling@lzb.ac.cn (Chouyaling)

 

 

 ABSTRACT

The structural characteristics are the basic attributes, which have a strong influence on engineering properties of soil. The effect of structural characteristics on the mechanical properties of frozen loess has been investigated. Based on triaxial compression tests of remolded frozen loess and artificial structured frozen loess with different content of cement,this paper studied how the confining pressure, initial water content, temperature and the cement amount influenced the frozen loess' strength behavior. The test results showed that in the same experiments, there were some differences of the stress-strain relationship between the unsaturated and saturated frozen loess. The temperature and confining pressure were the main important factors that influenced the shearing strengths of frozen soil. The shearing strengths of unsaturated frozen loess are increasing with confining pressure, but that of saturated frozen loess has little relationship with confining pressure. The initial water content is another main factor affecting the frozen loess strength. As the increase of water content, the frozen loess strength is also increasing,but there is a peak point. After it the frozen loess strength would decrease gradually with the water content increasing, and the strength of saturated frozen loess reached the lowest. With regard to the unsaturated frozen loess, the yield strength and failure strength are both increasing with the content of cement. For the saturated frozen loess, the yield strength is increasing with the content of cement, too. However, the failure strength has little relationship with the cement content. The mentioned factors have obvious influence on the structural characteristics of frozen loess, however the cement content and water content are the dominating factors. The mechanical properties and structural characteristics of frozen loess depend on not only the single factor, such as confining pressure, initial water content, temperature and the cement amount etc., but also on the possible interaction between the mentioned factors. At last, the comprehensive coefficient M which correlates closely with parameters of shear strength was presented. By regression analysis, the exponential function relationship between M and c as well as M and tan? was obtained.

Keywords: Soil mechanics; Frozen loess; Artificial structured soil; Triaxial tests; Strength behavior

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