摘要
为探究恒定荷载作用下不同温差冻融循环对露天煤矿边坡岩体微观结构的影响规律,采用自主研发的TCDR-Ⅰ温度-应力耦合试验系统,在恒定荷载及不同温差冻融循环作用后,通过核磁共振测试及声波检测分析技术,得到饱水砂岩冻融循环前后内部孔隙及孔喉分布的变化规律。研究结果表明:随着冻融循环下限温度降低,饱水砂岩内部损伤因子逐渐增大;冻融砂岩孔隙度增比随下限温度降低呈指数型增加,温差越大对孔隙结构的影响更为显著;荷载砂岩冻融循环过程中,小孔喉的增幅和中大孔喉降幅随下限温度降低呈线性增加;砂岩内部孔结构分形维数与下限温度之间呈负相关,荷载砂岩冻融循环孔隙结构表现出多重分形特征,小孔隙分形维数从-10~20℃时的2.308增加到-40~20℃时的2.558,孔喉分形维数处于2.967~2.983之间。研究结果可为寒区露天矿岩质边坡季节性破坏机理及裂隙演化研究提供参考。
In order to investigate the influence of different temperature difference freeze-thaw cycle on the microstructure of rock body of open-pit coal mine slope under the action of constant load,the self-developed TCDR-Ⅰtemperature-stress coupling test system was used to obtain the change law of internal pore and pore throat distribution of water-saturated sandstone before and after freeze-thaw cycle through the nuclear magnetic resonance test and acoustic wave detection and analysis technology after the action of constant load and freeze-thaw cycle with different temperature difference.The results show that as the lower limit temperature of freeze-thaw cycle decreases,the internal damage factor of water-saturated sandstone increases gradually.The porosity increase ratio of freeze-thaw sandstone increases exponentially as the lower limit temperature decreases,and the larger the temperature difference is,the influence on the pore structure is more significant.The increase of small pore throats and the decrease of medium and large pore throats of the loaded sandstone during the freeze-thaw cycle increase linearly with the decrease of the lower limit temperature.The fractal dimensions of the pore structure in the sandstone are negatively correlated with the lower limit temperature,and the pore structure of loaded sandstone during freeze-thaw cycle presents multiple fractal characteristics,with the fractal dimension of small pores increasing from 2.308 at-10℃~20℃to 2.558 at-40℃~20℃,and the fractal dimension of pore throats ranges from 2.967 to 2.983.The research results can provide a reference for the study of seasonal damage mechanism and fracture evolution of rocky slopes in open-pit mines in cold regions.
作者
张晓龙
徐培耘
林海飞
胡彪
陈晓旭
王锴
苟锐
ZHANG Xiaolong;XU Peiyun;LIN Haifei;HU Biao;CHEN Xiaoxu;WANG Kai;GOU Rui(School of Safety Science and Engineering,Xi’an University of Science and Technology,Xi’an Shaanxi 710054,China;Western Coal Mine Gas Disaster Prevention and Control Key Laboratory of Shaanxi Higher Education Institutions,Xi’an Shaanxi 710054,China)
出处
《中国安全生产科学技术》
CAS
CSCD
北大核心
2024年第11期60-69,共10页
Journal of Safety Science and Technology
基金
国家重点研发计划项目(2022YFF1302601)
陕西省教育厅青年创新团队项目(23JP097)
陕西省教育厅一般专项项目(23JK0546)。
关键词
冻融温差
核磁共振
孔隙度
孔喉
分形维数
freeze-thaw temperature difference
nuclear magnetic resonance
porosity
pore throat
fractal dimension
