Ring shear tests on slip soils and their enlightenment to critical strength of reservoir landslides
FAN Zhi-qiang1, 3, TANG Hui-ming1, 2, TAN Qin-wen1, YANG Ying-ming2, WEN Tao1
1. Faculty of Engineering, China University of Geosciences, Wuhan 430074, China; 2. Three Gorges Research Center for Geo-hazard, Ministry of Education, Wuhan 430074, China; 3. University College London, London WC1E 6BT, England
Abstract：The critical strength of landslides is important for their researches, and how to evaluate it accurately has been the focus and nodus. Conducting ring shear tests on slip soils can obtain the peak and residual strength parameters, and it is helpful to reveal the shearing properties of the soils. Thus, the ring shear tests on the slip soils sampled from Huangtupo landslide are carried out, and two normal stress partitions (namely high- and low-stress subareas) are determined with the boundary stress value of 180 kPa. Then, the soil strengths in this two stress partitions are studied. As a result, the post-peak strength-softening mechanism dominated by the decrease of cohesion (decreased by 44.8% in the high-stress subarea, and 93.8% in the low-stress subarea) and the constant of frictional angle (the difference between peak and residual frictional angles in the high-stress subarea is 0.136°, but 0.468° in the low-stress subarea) is illuminated for the slip soils. By employing a weakening coefficient of cohesion, the back analysis method is adopted to study the critical strength of the reservoir landslide under different working conditions. Eventually, by considering the variation of slope stress and the softening-properties of the soils, the reasons why the critical strength is related with the working conditions are discussed, and their enlightening significance and engineering significance are also expounded.
范志强, 唐辉明, 谭钦文, 杨迎铭, 温韬. 滑带土环剪试验及其对水库滑坡临滑强度的启示[J]. 岩土工程学报, 2019, 41(9): 1698-1706.
FAN Zhi-qiang, TANG Hui-ming, TAN Qin-wen, YANG Ying-ming, WEN Tao. Ring shear tests on slip soils and their enlightenment to critical strength of reservoir landslides. Chinese J. Geot. Eng., 2019, 41(9): 1698-1706.
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