Experimental study on mechanical properties of lime modified loess under freeze-thaw cycle
Hu Zaiqiang1,2 Liang Zhichao1 Wu Chuanyi1 She Haicheng1,2 Feng Zhe1 Guo Jing1
1. Institute of Geotechnical Engineering, Xi'an University of Technology, Shaanxi 710048, China;
2. Key Laboratory of Destruction Mechanism and Control Technology of Earth and Rock Dam of Ministry of Water Resources, Nanjing 210024, China
Abstract： The compaction test of lime modified loess was carried out, and the change rules of lime content, optimal water content and maximum dry density of modified loess were obtained. At the same time, the consolidation and drainage shear tests of lime-modified loess were carried out with triaxial shear apparatus under freeze-thaw cycle, so as to study the mechanical properties of lime-modified loess under freeze-thaw cycle. The results show that the optimal water content increases with the increase of lime content, but the maximum dry density decreases. Under different lime content, the stress-strain curve of modified loess after freeze-thaw cycle changes from weak hardening type to weak softening type with the increase of freeze-thaw cycle times, and finally tends to strong softening type. With the increase of freeze-thaw cycle times, the failure strength showed a downward trend. When the lime content was 6% and the freeze-thaw times were 10 times, the higher the confining pressure was, the smaller the failure strength attenuation rate was. The cohesive force of lime-modified loess decreases with the increase of freeze-thaw cycle times, and finally tends to be stable, while the internal friction Angle remains almost unchanged. When lime content is constant, with the increase of freeze-thaw cycle times, the structural parameters decrease and the change trend is small. With a certain number of freeze-thaw cycles, the structural parameters tend to decrease with the increase of lime content. At the same time, with the ncrease of confining pressure, structural parameters also show a decreasing trend, and the relationship curve between structural parameters and axial strain changes from strong softening type to weak softening type with the increase of confining pressure.
