Geomechanical and Acoustic Properties of Intact Granite Subjected to Freeze–Thaw Cycles during Water-Ice Phase Transformation in Beizhan’s Open Pit Mine Slope, Xinjiang, China

Water

Wenkai Feng¹  Huajian Wang²  Yu Wang³  Changhong Li³  Jianqiang Han⁴ 

[1] Resource Engineering, University of Science &Technology Beijing, Beijing 100083, China;;Beijing Key Laboratory of Urban Underground Space Engineering, Department of Civil Engineering, School of Civil &State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu 610059, China;

关键词: freeze thaw;    uniaxial compression;    acoustic emission (ae);    ultrasonic measurement;    energy conversion;   

DOI  :  10.3390/w11112309

来源: DOAJ

【 摘 要 】

The deterioration of rock geomechanical behaviors subjected to freeze−thaw (F−T) action is a determining factor for rock engineering and rock structures in cold regions. In this work, taking six groups of granite obtained from an open pit mine as the research object, F−T cycle treatment, in-situ AE (acoustic emission) monitoring and ultrasonic detection techniques were performed to experimentally reveal the effects of F−T fatigue damage on the mechanical and acoustic properties of granite. The results indicate that the F−T action impacts the rock’s mesoscopic structure, deformation, strength, P and S-wave velocities, AE pattern and energy release. The accumulated AE counts and accumulated AE energy show a decreasing trend as the F−T cycle increases. The frequency spectrum revealed that the width of the low frequency band decreases and the high frequency band increases with increasing F−T cycles, indicating that there is an increase in large-scale cracks for a sample with high F−T treatment. In addition, energy balance analysis further illustrates the energy dissipation and release mechanism. The energy proportion used to drive the crack propagation is relatively small with high F−T treatment, and the final released energy becomes the minimum. The energy evolution characteristics analyzed by the energy balance approach is in good agreement with AE results. It is suggested that the F−T fatigue damage influences the rock energy storage and release characteristics and the instability of rock in the cold regions.

【 授权许可】

Unknown