Collapse mechanism of gentle expansive soil slope in drying and wetting cycles

被引：0
|
作者：
Yang G. [1 ]
Chen Z. [1 ]
Zhang H. [2 ]
Duan J. [1 ]
Xia X. [1 ]
Lin Y. [1 ]
机构：
[1] School of Civil Engineering, Central South University, Changsha
[2] Guangxi Transportation Science and Technology Group Co. Ltd., Nanning
来源：
Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology) | 2022年 / 53卷 / 01期
基金：
中国国家自然科学基金;
关键词：
Collapse failure; Drying and wetting cycles; Expansive soil slope; Safety factor; Shear strength parameters;
D O I：
10.11817/j.issn.1672-7207.2022.01.005
中图分类号：
学科分类号：
摘要：
In order to analyze the evolution characteristics and mechanism of the collapse of a gentle expansive soil slope, an expansive soil slope in Ningming, Guangxi Zhong Autonomous Region, was regarded as a physical project for comprehensive study. Combined with the results of light dynamic penetration tests and the damage of the installed inclinometer tubes, the depth and shape of the sliding surface of the expansive soil slope were obtained. Then, the difference of shear strength parameters between the expansive soil in the slope body in wetting and drying cycles and the expansive soil at the sliding surface of the slope was compared and analyzed through wetting-drying tests and direct shear tests. Finally, the expansion force was introduced to obtain the calculation formula for the stability of the expansive soil slope based on the Janbu method, and the change law of the safety factor of the expansive soil slope in wetting and drying cycles was analyzed through the engineering project. The results show that the failure of the Ningming expansive soil slope is a shallow collapse failure characterized by tensile cracking, and subsidence at the rear edge of the sliding body and arc-shaped shear sliding at the front edge of the sliding body. The internal friction angle of the expansive soil is basically unchanged with the increase of the number of wetting and drying cycles, while the cohesive force decreases exponentially. The cohesive force of expansive soil in the slope is stable at 10.3 kPa after 8 drying and wetting cycles, which is basically the same as the cohesive force of expansive soil at the sliding surface of the slope on-site. The stability of the expansive soil slope decreases after considering the expansive force. The safety factor of the slope decreases with the increase of drying and wetting cycles, and the slope tends to be unstable after 8 drying and wetting cycles, which is consistent with the actual development law of the slope failure, indicating that the effect of drying and wetting cycles is the key reason for the shallow collapse of the expansive soil slope. © 2022, Central South University Press. All right reserved.
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页码：95 / 103
页数：8
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