Study on creep mechanical properties of frozen cretaceous sandstone during thawing process

被引：0
|
作者：
Li Z. [1 ]
Yang G. [1 ]
Wei Y. [2 ]
机构：
[1] College of Architecture and Civil Engineering, Xi'an University of Science and Technology, Xi'an
[2] State Key Laboratory of Road Engineering Safety and Health in Cold and High-altitude Regions, CCCC First Highway Consultants Co., Ltd., Xi'an
来源：
| 1777年 / Biodiversity Research Center, Academia Sinica卷 / 40期
基金：
中国国家自然科学基金;
关键词：
Creep characteristics; Cretaceous; Fractional-order theory; Frozen sandstone; Rock mechanics; Thawing process;
D O I：
10.13722/j.cnki.jrme.2021.0413
中图分类号：
学科分类号：
摘要：
After construction, shaft freezing walls will experience a long thawing process, creep deformation will occur under long-term loads. The creep behavior of frozen rocks during the thawing process is the key issue to control the long-term stability of the frozen walls. Based on the freezing engineering of the return air shaft in Xinzhuang Coal Mine, Gansu, this paper analyzes the creep mechanical characteristics of the frozen Cretaceous sandstone during the thawing process. At the same time, nuclear magnetic resonance technology is used to test the change of the pore water content during the thawing process to analyze the relationship between the unfrozen water and the sandstone strength. Based on the fractional order theory, a nonlinear creep constitutive equation is established. The results show that the pore water in rocks mainly presents three forms such as free water, capillary water and adsorbed water, mainly exists in the forms of free water at room temperature and adsorbed water at low temperature. During the thawing process of frozen sandstone, the long-term strength, gradually decreasing with increasing temperature, is about 45%~-51% of the conventional triaxial compressive strength, and changes suddenly at -4 ℃. It is also found that the long-term strength of the frozen sandstone is closely related to the unfrozen water content, showing an exponential function. The creep failure of the frozen sandstone is mainly due to the coupling of stress field, chemical potential field and seepage field, and the stress field plays a leading role. According to the creep deformation characteristics of the frozen sandstone during the thawing process, and introducing a fractional order function, a corresponding nonlinear creep equation is established based on the fractional order theory. The research results can provide theoretical and technical support for evaluating the instability and damage of frozen walls induced by the thawing. © 2021, Science Press. All right reserved.
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页码：1777 / 1788
页数：11
相关论文
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