水泥-粉煤灰基矸石胶结充填体破坏特征及强度形成机制  

Failure characteristics and strength formation mechanism of cement-fly ash based cemented gangue backfill

作　　者：李晓磊 杜献杰 冯国瑞[1,2,3,6] 巨峰 王建伟[5] 刘文昊 郑远翔 LI Xiaolei;DU Xianjie;FENG Guorui;JU Feng;WANG Jianwei;LIU Wenhao;ZHENG Yuanxiang(College of Mining Engineering,Taiyuan University of Technology,Taiyuan 030024,China;Shanxi Key Laboratory of Mine Rock Strata Control and Disaster Prevention,Taiyuan 030024,China;Shanxi-zheda Institute of Advanced Materials and Chemical Engineering,Taiyuan 030032,China;State Key Laboratory of Deep Geotechnical Mechanics and Underground Engineering,China University of Mining and Technology,Xuzhou 221116,China;Zhengzhou Coal industry(Group)Co.,Ltd.,Zhengzhou 450042,China;Shanxi Energy College,Jinzhong 030604,China)

机构地区：[1]太原理工大学矿业工程学院,山西太原030024 [2]矿山岩层控制及灾害防控山西省重点实验室,山西太原030024 [3]山西浙大新材料与化工研究院,山西太原030032 [4]中国矿业大学深部岩土力学与地下工程国家重点实验室,江苏徐州221116 [5]郑州煤炭工业(集团)有限责任公司,河南郑州450042 [6]山西能源学院,山西晋中030604

出　　处：《煤炭科学技术》2024年第5期36-45,共10页Coal Science and Technology

基　　金：国家自然科学基金资助项目(52004173);山西浙大新材料与化工研究院科研项目(2022SX-TD008);中国博士后科学基金面上资助项目(2022M712922)。

摘　　要：在煤矿结构充填开采中,不同充填率条件下对矸石胶结充填体强度的需求不同,拟通过改变粉煤灰在水泥–粉煤灰二元胶凝材料用量中的占比(下称“粉煤灰占比”)调控矸石胶结充填体强度,对不同粉煤灰占比(0~90%)矸石胶结充填体进行单轴压缩试验,探明矸石胶结充填体的强度调控范围,结合数字图像相关技术对试样破坏形态进行分析,结合声发射事件对试样脆延性破坏模式进行分析。采用承压筒法和单轴压缩试验分别测定了煤矸石的强度和不同粉煤灰占比水泥–粉煤灰二元胶凝材料的强度,并根据煤矸石的强度与水泥–粉煤灰二元胶凝材料的强度关系揭示矸石胶结充填体的强度形成机制。研究结果表明:矸石胶结充填体强度随着粉煤灰占比的增加而减少,实现了较大的矸石胶结充填体强度调控范围:1.77~30.04 MPa。不同强度范围的矸石胶结充填体试样对应的破坏形态和脆延性破坏模式也不同,材料性质发生了质的变化。随着粉煤灰占比的增加,在破坏形态方面,矸石胶结充填体试样由剪切破坏(0~50%粉煤灰占比)向拉剪复合破坏(60%~80%粉煤灰占比)再向拉伸破坏(90%粉煤灰占比)转变,对应的强度范围分别为20.8~30.04 MPa,5.63~12.35 MPa和1.77 MPa;在脆延性破坏模式方面,试样由脆–延性破坏(0~40%粉煤灰占比)转变为延性破坏(50%~90%粉煤灰占比),对应的强度范围分别为24.64~30.04 MPa和1.77~20.8 MPa。矸石胶结充填体的强度由水泥–粉煤灰二元胶凝材料的强度(1.43~55.5 MPa)和煤矸石的强度(平均强度为4.43 MPa)共同决定。水泥–粉煤灰二元胶凝材料对矸石胶结充填体的强度贡献较大,煤矸石使矸石胶结充填体的强度受限。所得试验结果为结构充填中充填材料的强度选择提供参考。In the process of constructional backfilling coal mining(CBCM),the demand for the strength of cemented gangue backfill(CGB)samples varies with different backfill rates.It is planned to adjust the strength of CGB samples by changing the proportion of fly ash in the dosage of cement-fly ash binary cementitious material(hereinafter referred to as the proportion of fly ash),and conduct uniaxial compression tests on CGB samples with different proportions of fly ash(0−90%)to explore the range of strength control of CGB samples,and analyze the failure morphology of the samples using digital image correlation technology,and analyze the brittle ductile failure mode of the samples using AE events.The strength of coal gangue and the strength of cement-fly ash binary cementitious material with different fly ash proportions are measured using the pressure cylinder method and uniaxial compression test,respectively,and the mechanism of strength formation of CGB samples is revealed based on the relationship between the strength of coal gangue and the strength of cement-fly ash binary cementitious material.The research results indicate that the strength of CGB decreases with the increase of proportion of fly ash,achieving a larger range of strength control for CGB:1.77−30.04 MPa.The failure morphology and the brittle ductile failure mode of samples with different replacement rates of CGB samples are different,and the corresponding strength range of the samples is also differ-ent,Material properties have undergone fundamental changes.As the proportion of fly ash increases,in terms of the failure morphology,CGB samples transition from shear failure(0−50%proportion of fly ash)to tensile shear composite failure(60%−80%proportion of fly ash)and then to tensile failure(90%proportion of fly ash),corresponding to the strength ranges are 20.8−30.04 MPa,5.63−12.35 MPa,and 1.77 MPa;In terms of the brittle ductile failure mode,the samples transition from brittle-ductile failure(0−40%proportion of fly ash)to ductile failure(50%�

关 键 词：粉煤灰占比 矸石胶结充填体 单轴压缩试验 承载特征 强度调控 强度形成机制 

分 类 号：TD823[矿业工程—煤矿开采]