高寒地区厚煤层上冻土体冻融循环后破坏特征研究  

Study on the Failure Characteristics of Frozen Soil After Freeze-Thaw Cycle on Thick Coal Seam in High Cold Area

作　　者：李辉 陈勇升 李鑫林 许金梦 温佳民 LI Hui;CHEN Yongsheng;LI Xinlin;XU Jinmeng;WEN Jiamin(China Coal Energy Group Co.,Ltd.,Beijing 100120,China;College of Energy and Mining,China University of Mining and Technology-Beijing,Beijing 100083,China;Engineering Research Center of Green and Intelligent Mining for Thick Coal Seam,Ministry of Education,Beijing 100083,China;Inner Mongolia Research Institute,China University of Mining and Technology-Beijing,Ordos,Inner Mongolia 017000,China;China National Coal Development Co.,Ltd.,Beijing 100011,China)

机构地区：[1]中国中煤能源集团有限公司,北京100120 [2]中国矿业大学(北京)能源与矿业学院,北京100083 [3]厚煤层绿色智能开采教育部工程研究中心,北京100083 [4]中国矿业大学(北京)内蒙古研究院,内蒙古鄂尔多斯市017000 [5]中国煤炭开发有限责任公司,北京100011

出　　处：《矿业研究与开发》2024年第3期114-120,共7页Mining Research and Development

基　　金：国家自然科学基金项目(51974320,51934008,52121003);中央高校基本业务费(2023YQTD02).

摘　　要：为了揭示高寒地区厚煤层上冻土体冻融循环破坏特征,以高寒地区厚煤层上冻土体为研究对象,采用电液伺服岩石单轴实验机进行岩石力学试验,利用非金属超声波检测仪测试人工试件波速,得到了在不同含水量下冻融循环次数对于冻土体结构、峰值强度、弹性模量以及裂隙发育的影响特征。研究结果表明,随着冻融循环次数增加,一定含水率条件下的人工冻土试件的峰值强度-冻融循环次数和弹性模量-冻融循环次数的拟合函数关系曲线均为“开口向下”的抛物线,弹性模量以及峰值强度的降幅取决于应变累积速度以及损伤发展速度;随着冻融循环次数增加,人工冻土试件的波速逐渐减小,即内部孔隙、裂隙发育状况良好。从细观力学角度分析,历经数次冻融循环后,冻土渗透系数逐渐增大,水分迁移速度加快,冻胀力作用效果明显,细颗粒土逐渐被压实,同时产生大量的新生微裂隙,孔隙率逐渐增大。In order to reveal the failure characteristics of frozen soil after freeze-thaw cycle on thick coal seam in high-altitude and cold region,taking the frozen soil body on the thick coal seam in high cold area as the research object,electro-hydraulic servo rock uniaxial experimental machine was used to carry out the rock mechanics experiments.The influence characteristics of freeze-thaw cycles on the structure,peak strength,elastic modulus,and crack development of frozen soil body were obtained by a non-metallic ultrasonic detector to test the wave velocity of artificial specimens with different water contents.It is concluded that under a certain water content condition,as the number of freeze-thaw cycles increases,the fitting function curves of the peak strength and freeze-thaw cycle number,as well as the elastic modulus and freeze-thaw cycle number of artificially frozen soil specimens are both parabolas with an opening downward.The decrease in elastic modulus and peak strength depends on the rate of strain accumulation and damage development.As the number of freeze-thaw cycles increases,the wave velocity of artificially frozen soil specimens gradually decreases,indicating good development of internal pores and cracks.From the perspective of micromechanics,after several freeze-thaw cycles,the permeability coefficient of frozen soil gradually increases,the speed of water migration accelerates,and the effect of frost heave force is obvious.Fine grained soil is gradually compacted,while a large number of new-born micro cracks are generated,and the porosity gradually increases.

关 键 词：冻融循环 厚煤层 冻土体 孔隙率 冻胀力 

分 类 号：TD315[矿业工程—矿井建设] TU445[建筑科学—岩土工程]