Peng Muwen, Zuo Shuangying, Yang Guosheng, et al. 2022. Experimental study on damage characteristics of Guiyang red clay under cyclic loading and unloading[J]. Journal of Engineering Geology, 30(5): 1466-1476. doi: 10.13544/j.cnki.jeg.2022-0461.
    Citation: Peng Muwen, Zuo Shuangying, Yang Guosheng, et al. 2022. Experimental study on damage characteristics of Guiyang red clay under cyclic loading and unloading[J]. Journal of Engineering Geology, 30(5): 1466-1476. doi: 10.13544/j.cnki.jeg.2022-0461.

    EXPERIMENTAL STUDY ON DAMAGE CHARACTERISTICS OF GUIYANG RED CLAY UNDER CYCLIC LOADING AND UNLOADING

    • This paper studies the damage characteristics of Guiyang red clay under cyclic loading and reveals the evolution of shear strength parameters with the loading and unloading process. Using the stress path test module in the stress-strain controlled triaxial shear penetrometer,we conducted consolidation undrained shear cyclic loading and unloading tests on Guiyang red clay with four water contents of ω=29%,32%,35% and 38% at σ3=100 kPa,200 kPa and 300 kPa surrounding pressure,respectively. This study shows the follows. The soil samples exhibit deformation enhancement during unloading,the larger the axial strain increment after unloading,the longer the relaxation time,and the larger the rebound deformation. Taking into account the effects of water content and surrounding pressure conditions,we established the mathematical relational equation for the evolution of elastic deformation during shearing of Guiyang red clay. We compared the mathematical relational equation with the experimental results to verify that the fit was more than 95%. We adopted the equivalent plastic shear strain as the plastic internal variable to study the strength damage characteristics of Guiyang red clay during the whole shear process. The results found that its cementation strength kept losing while the friction strength kept increasing. With the increase of water content,the internal friction angle and cohesiveness range from 21.8°to 16.1°and 83.7 kPa to 57.5 kPa,respectively. The research is expected to provide theoretical guidance for the compaction of road base and the evaluation of soil slope stability considering the loading and unloading conditions.
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