Experimental studies on the pore structure and mechanical properties of anhydrite rock under freeze-thaw cycles
冻融循环作用下硬石膏岩孔隙结构及力学性能试验研究
凍結融解サイクル下の硬石膏岩の細孔構造と機械的性質に関する実験的研究
동결-해동 주기에 따른 무수석고 암석의 공극 구조 및 기계적 특성에 관한 실험적 연구
Estudios experimentales sobre la estructura de poros y propiedades mecánicas de la roca de anhidrita bajo ciclos de congelación-descongelación
Études expérimentales sur la structure des pores et les propriétés mécaniques de la roche anhydrite sous cycles de gel-dégel
Экспериментальные исследования пористой структуры и механических свойств ангидритной породы в условиях замораживания-оттаивания
Chao Hou 候超 ¹, Xiaoguang Jin 靳晓光 ¹ ² ³, Jie He 何洁 ¹, Hanlin Li 李翰林 ¹
¹ School of Civil Engineering, Chongqing University, Chongqing, 400045, China
中国 重庆 重庆大学土木工程学院
² Key Laboratory of New Technology for Construction of Cities in Mountain Area of the Ministry of Education, Chongqing University, Chongqing, 400045, China
中国 重庆 重庆大学 山地城镇建设与新技术教育部重点实验室
³ State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing, 400045, China
中国 重庆 重庆大学 煤矿灾害动力学与控制国家重点实验室
Journal of Rock Mechanics and Geotechnical Engineering, 4 December 2021
Abstract
To study the deterioration mechanisms of anhydrite rock under the freeze-thaw weathering process, the physico-mechanical characteristics and microstructure evolutions of anhydrite samples were determined by a series of laboratory tests. Then, a descriptive-behavioral model was used to measure the integrity loss in anhydrite samples caused by cyclic freeze-thaw. Finally, the freeze-thaw damage mechanisms of anhydrite rock were revealed from the macro and micro aspects.
The results show that the pore size of the anhydrite rock is mainly concentrated in the range of 0.001–10 μm. As the number of freeze-thaw cycles increases, there is a growth in the proportion of macropores and mesopores. However, the proportion of micropores shows a declining trend. The relations of the uniaxial compressive strength, triaxial compressive strength, cohesion, and elastic modulus versus freeze-thaw cycles can be fitted by a decreasing exponential function, while the internal friction angle is basically unchanged with freeze- thaw cycles. With the increase of confining pressure, the disintegration rates of the compressive strength and the elastic modulus decrease, and the corresponding half-life values increase, which reveals that the increase of confining pressures could inhibit freeze-thaw damage to rocks.
Moreover, it has been proven that the water chemical softening mechanism plays an essential role in the freeze-thaw damage to anhydrite rock. Furtherly, it is concluded that the freeze-thaw weathering process significantly influences the macroscopic and microscopic damages of anhydrite rock.
