充填体单轴压缩峰后应力—应变曲线特征及声发射参数研究
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摘要
低强度充填体在充填法开采中控制地压时可能处于峰后破坏阶段,其峰后应力—应变曲线特征及声发射参数与地压控制关系密切。以程潮铁矿灰砂比为1∶6的全尾砂胶结充填体为研究对象,开展了充填体单轴压缩及声发射监测试验,得到充填体单轴压缩下的应力—应变曲线及声发射参数,采用能率和声发射事件对峰后应力—应变曲线特征及破坏过程进行了分析。结果表明:充填体峰后应力—应变曲线斜率为负值,先逐渐减小,后逐渐增大,最后基本保持不变,根据峰后应力—应变曲线斜率变化趋势可将其划分为AB段、BC段及C以后段,其中AB段应力—应变曲线逐渐变陡,斜率逐渐减小,呈上凸型,充填体表面宏观裂纹不断增多,强度劣化加速,能率先急剧减小后快速增大,声发射事件定位点局部比较集中;BC段应力—应变曲线变缓,斜率逐渐增大,呈上凹型,剪切裂纹扩展、汇合形成宏观剪切面,破坏过程变缓,能率较高且逐渐下降,声发射事件定位点聚集呈带状分布;C以后段应力—应变曲线斜率基本不变,剪切面出现滑移,充填体残余结构支撑外部荷载,能率和声发射事件大幅下降;充填体峰后声发射参数能较好地反映其应力—应变曲线特征及破坏过程。
Low-strength cemented tailings backfill(CTB)may be in the post-peak failure stage when controls ground pressure in backfill mining.The post-peak stress-strain curve characteristics and the acoustic emission(AE)parameters of CTB are closely related to the control of ground pressure.Therefore,uniaxial compression experiments and AE tests of CTB from unclassified tailings of Chengchao Iron Mine with cement-tailing ratio of 1:6 are conducted to obtain the stress-strain curve and the AE parameters.The post-peak stress-strain curve characteristics and failure process of CTB are analyzed based on AE energy rate and AE event.The result shows that the slope value of the post-peak stress-strain curve of CTB is negative,which decreases firstly,then increases and keeps a constant finally.The post-peak stress-strain curve could be divided into stage AB,stage BC and stage after C according to its slope variation.During stage AB,the stress-strain curve gradually becomes steeper and its slope value decreases with a convex sharp.The macroscopic cracks on the surface of the filling body increase gradually and the strength deterioration accelerates.The energy rate decreases dramatically,then increases rapidly and AE event location point concentrate partly.When the CTB enters the BC stage,the stress-strain curve becomes slow and its slope increase with a concave sharp.The macroscopic shear plain appears because of the expansion and convergence of shear cracks and the failure process becomes slower. The energy rate is high and decreases with AE event location points gathering into a strip.At the stage after C,the slope of the stress-strain curve keeps a constant.The shear plain slips and external load is supported by residual structure of CTB.Meanwhile,the energy rate and AE event reduce significantly.The post-peak AE parameters of CTB can well reflect its characteristics of stress-strain curve and the failure process.
Low-strength cemented tailings backfill(CTB)may be in the post-peak failure stage when controls ground pressure in backfill mining.The post-peak stress-strain curve characteristics and the acoustic emission(AE)parameters of CTB are closely related to the control of ground pressure.Therefore,uniaxial compression experiments and AE tests of CTB from unclassified tailings of Chengchao Iron Mine with cement-tailing ratio of 1:6 are conducted to obtain the stress-strain curve and the AE parameters.The post-peak stress-strain curve characteristics and failure process of CTB are analyzed based on AE energy rate and AE event.The result shows that the slope value of the post-peak stress-strain curve of CTB is negative,which decreases firstly,then increases and keeps a constant finally.The post-peak stress-strain curve could be divided into stage AB,stage BC and stage after C according to its slope variation.During stage AB,the stress-strain curve gradually becomes steeper and its slope value decreases with a convex sharp.The macroscopic cracks on the surface of the filling body increase gradually and the strength deterioration accelerates.The energy rate decreases dramatically,then increases rapidly and AE event location point concentrate partly.When the CTB enters the BC stage,the stress-strain curve becomes slow and its slope increase with a concave sharp.The macroscopic shear plain appears because of the expansion and convergence of shear cracks and the failure process becomes slower. The energy rate is high and decreases with AE event location points gathering into a strip.At the stage after C,the slope of the stress-strain curve keeps a constant.The shear plain slips and external load is supported by residual structure of CTB.Meanwhile,the energy rate and AE event reduce significantly.The post-peak AE parameters of CTB can well reflect its characteristics of stress-strain curve and the failure process.
引文
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[2]王新民,李天正,陈秋松,等.基于变权重理论和TOPSIS的充填方式优选[J].中南大学学报:自然科学版,2016,47(1):198-203.Wang Xinmin,Li Tianzheng,Chen Qiusong,et al.Filling way optimization based on variable weight theory and TOPSIS[J].Journal of Central South University:Science and Technology,2016,47(1):198-203.
[3]刘艳章,张群,叶义成,等.挂帮矿开采低段高无底柱留矿嗣后充填采矿法[J].金属矿山,2014(12):40-44.Liu Yanzhang,Zhang Qun,Ye Yicheng,et al.Pillarless ore-remaining subsequent fill mining with low stageheight applicable to the exploitation of hanging wall ore[J].Metal Mine,2014(12):40-44.
[4]Famam Y,Geiker M R,Bentz D,et al.Acoustic emission waveform characterization of crack origin and mode in fractured and ASRdamaged concrete[J].Cement and Concrete Composites,2015,60:135-145.
[5]吴永胜,余贤斌.单轴压缩条件下岩石声发射特性的实验研究[J].金属矿山,2008(10):25-28.Wu Yongsheng,Yu Xianbin.Experimental study on the acoustic emission characteristics of rocks at uniaxial compression[J].Metal Mine,2008(10):25-28.
[6]李术才,许新骥,刘征宇,等.单轴压缩条件下砂岩破坏全过程电阻率与声发射响应特征及损伤演化[J].岩石力学与工程学报,2014,33(1):14-23.Li Shucai,Xu Xinji,Liu Zhengyu,et al.Electrical resistivity and acoustic emission response characteristics and damage evolution of sandstone during whole process of uniaxial compression[J].Chinese Journal of Rock Mechanics and Engineering,2014,33(1):14-23.
[7]Xu X L,Zhang Z Z.Acoustic emission and damage characteristics of granite subjected to high temperature[J].Advances in Materials Science and Engineering,2018(4):1-12.
[8]唐珺,刘卫群,费晓东.峰后岩石类材料的声发射特性研究[J].煤炭科学技术,2011,39(5):21-24.Tan Jun,Liu Weiqun,Fei Xiaodong.Study on after peak acoustic emission features of rock type material[J].Coal Science and Technology,2011,39(5):21-24.
[9]龚囱,李长洪,赵奎.加卸荷条件下胶结充填体声发射b值特征研究[J].采矿与安全工程学报,2014,31(5):788-794.Gong Cong,Li Changhong,Zhao Kui.Experimental study on b-value characteristics of acoustic emission of cemented filling body under loading and unloading tes[tJ].Journal of Mining&Safety Engineering,2014,31(5):788-794.
[10]谢勇,何文,朱志成,等.单轴压缩下充填体声发射特性及损伤演化研究[J].应用力学学报,2015,32(4):670-676.Xie Yong,He Wen,Zhu Zhicheng,et al.Study on backfill acoustic emission characteristic and damage evolution under uniaxial compression[J].Chinese Journal of Applied Mechanics,2015,32(4):670-676.
[11]孙光华,魏莎莎,刘祥鑫.基于声发射特征的充填体损伤演化研究[J].实验力学,2017,32(1):137-144.Sun Guanghua,Wei Shasha,Liu Xiangxin.On the damage evolution of fillings based on acoustic emission characteristics[J].Journal of Experimental Mechanics,2017,32(1):137-144.
[12]殷正钢.岩石破坏过程中的声发射特征及其损伤实验研究[D].长沙:中南大学,2005.Yin Zhenggang.Acoustic Emission Characteristics and Injury Ex-perimental Study in the Process of Rock Failure[D].Changsha:Central South University,2005.
[13]徐文彬,宋卫东,王东旭,等.三轴压缩条件下胶结充填体能量耗散特征分析[J].中国矿业大学学报,2014,43(5):808-814.Xu Wenbin,Song Weidong,Wang Dongxu,et al.Energy dissipation properties of cement backfill body under triaxial compression conditions[J].Journal of China University of Mining and Technology,2014,43(5):808-814.
[14]阳明纬.声发射检测[M].北京:机械工业出版社,2005.Yang Mingwei.Acoustic Emission Detection[M].Beijing:Mechanical Industry Press,2005.
[15]李浩然,杨春和,刘玉刚,等.单轴荷载作用下盐岩声波与声发射特征试验研究[J].岩石力学与工程学报,2014,33(10):2107-2116.Li Haoran,Yang Chunhe,Liu Yugang,et al.Experimental study on ultrasonic velocity and acoustic emission properties of salt rock under uniaxial compression load[J].Journal of Rock Mechanics and Engineering,2014,33(10):2107-2116.