基于场应变的充填体与围岩组合模型循环加卸载试验研究
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摘要
为模拟研究充填采场围岩破裂演变机理,设计了充填体与围岩组合模型,采用RLW-3000微机控制剪切蠕变试验机对不同种类岩石模型试样进行了不同侧压力条件下的循环加卸载试验;通过VIC-3D非接触全场应变系统同步监测模型试样损伤破坏过程,基于试验过程中应变场的演变,对组合模型破裂机理进行了分析。研究表明:充填体能够增强围岩的完整性及强度;组合模型的破裂经历了一个扩容的过程;不同侧压下循环加卸载应力-应变曲线形成多塑性滞回环,岩性越软滞回现象越显著;应变场在低循环荷载时近似均匀场,高荷载时在加载非均匀场与卸载均匀场之间变换,渐呈应变局部化特征;张拉应变区首先出现在强度比较低的充填体区域,并随荷载增大逐渐向两侧的围岩移动,充填体与围岩变形具有时空非同步性与破坏形式差异;不同种类围岩破坏形式不同,强度较低的呈剪切破坏,强度较高的则为拉伸破坏。结果表明场应变演变可较好地表征充填采场围岩破裂过程。
A combined model of surrounding rock and backfill was designed to simulate the failure evolution of backfilled mining stope. Cyclic loading and unloading tests were conducted on model specimens of three different rocks( marble,granite,and basalt) by using RLW-3000 microcomputer-controlled shear creep test machine under varying lateral pressure; VIC-3D non-contact full-field strain measurement system was employed to simultaneously monitor the damage process and failure of the combined model. Analysis result demonstrates that backfill enhances the integrity and strength of surrounding rock; the combined model undergone a volume dilatation process. The stress-strain curves of the loading and unloading in every cyclic loading process are non-coincident,forming plastic hysteresis loops which becomes more remarkable with the increase of rock's softness. Strain field approximates uniform field under low cyclic load,while changes between non-uniform field of loading and uniform field of unloading under the condition of high load,exhibiting features of strain localization. Tensile strain firstly appeared in the region of backfill body of low strength,and gradually moves towards two sides of surrounding rock with the climbing of loading. The deformation and failure of backfill body and surrounding rock are asynchronous in spatial-temporal evolution with different failure modes. The failure mode varies with surrounding rock type: rock of low strength exhibits shear failure,and rock of high strength,tensile failure. The results suggest that the evolution of strain field could well reflect the fracture process of the combined model of surrounding rock and backfill.
A combined model of surrounding rock and backfill was designed to simulate the failure evolution of backfilled mining stope. Cyclic loading and unloading tests were conducted on model specimens of three different rocks( marble,granite,and basalt) by using RLW-3000 microcomputer-controlled shear creep test machine under varying lateral pressure; VIC-3D non-contact full-field strain measurement system was employed to simultaneously monitor the damage process and failure of the combined model. Analysis result demonstrates that backfill enhances the integrity and strength of surrounding rock; the combined model undergone a volume dilatation process. The stress-strain curves of the loading and unloading in every cyclic loading process are non-coincident,forming plastic hysteresis loops which becomes more remarkable with the increase of rock's softness. Strain field approximates uniform field under low cyclic load,while changes between non-uniform field of loading and uniform field of unloading under the condition of high load,exhibiting features of strain localization. Tensile strain firstly appeared in the region of backfill body of low strength,and gradually moves towards two sides of surrounding rock with the climbing of loading. The deformation and failure of backfill body and surrounding rock are asynchronous in spatial-temporal evolution with different failure modes. The failure mode varies with surrounding rock type: rock of low strength exhibits shear failure,and rock of high strength,tensile failure. The results suggest that the evolution of strain field could well reflect the fracture process of the combined model of surrounding rock and backfill.
引文
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[8]吴彬,胡伟华,唐克静,等.混凝土循环加卸载动态损伤演化推移分析及损伤值估计模型[J].长江科学院院报,2016,33(10):140-144.
[9]赵星光,李鹏飞,马利科,等.循环加、卸载条件下北山深部花岗岩损伤与扩容特性[J].岩石力学与工程学报,2014,33(9):1740-1748.
[10]焦贵德,赵淑萍,马巍,等.循环荷载下冻土的滞回圈演化规律[J].岩土工程学报,2013,35(7):1343-1349.
[11]赵闯,武科,李术才,等.循环荷载作用下岩石损伤变形与能量特征分析[J].岩土工程学报,2013,35(5):890-896.
[12]米红林.基于数字散斑相关法的岩石材料力学性能的测试[J].应用光学,2013,34(1):123-127.
[13]郭文婧,马少鹏,康永军,等.基于数字散斑相关方法的虚拟引伸计及其在岩石裂纹动态观测中的应用[J].岩土力学,2011,32(10):3196-3200.
[14]彭瑞东,翁炜,左建平,等.数字散斑相关法在SEM观测岩石变形时的应用[J].中国矿业大学学报,2012,41(4):650-656.
[15]宋义敏,马少鹏,杨小彬,等.岩石变形破坏的数字散斑相关方法研究[J].岩石力学与工程学报,2011,30(1):170-175.
[2]蔡嗣经,童光煦,高华林.胶结充填法?场围岩与充填体相互作用研究[J].江西有色金属,1992,6(2):93-96,101.
[3]秦帅,余一松,樊忠华,等.充填体与预留原岩矿柱相互作用机理研究[J].采矿技术,2011,(4):28-31.
[4]彭志华.胶结充填体力学作用机理及稳定性分析[J].有色金属(矿山部分),2009,61(1):39-41,49.
[5] LIU Zhi-xiang,LAN Ming,XIAO Si-you,et al. Damage Failure of Cemented Backfill and Its Reasonable Match with Rock Mass[J]. Transactions of Nonferrous Metals Society of China,2015,25(3),954-959.
[6] XUE De-ping,WANG Jian-peng. Deformation Failure Mechanism and Application of the Backfill along the Goaf-side Retained Roadway[J]. International Journal of Mining science and Technology,2013,23(3),329-335.
[7]马小亮,彭刚,吴彬,等.基于声发射循环加卸载时侧压混凝土损伤特性研究[J].长江科学院院报,2017,34(1):135-141.
[8]吴彬,胡伟华,唐克静,等.混凝土循环加卸载动态损伤演化推移分析及损伤值估计模型[J].长江科学院院报,2016,33(10):140-144.
[9]赵星光,李鹏飞,马利科,等.循环加、卸载条件下北山深部花岗岩损伤与扩容特性[J].岩石力学与工程学报,2014,33(9):1740-1748.
[10]焦贵德,赵淑萍,马巍,等.循环荷载下冻土的滞回圈演化规律[J].岩土工程学报,2013,35(7):1343-1349.
[11]赵闯,武科,李术才,等.循环荷载作用下岩石损伤变形与能量特征分析[J].岩土工程学报,2013,35(5):890-896.
[12]米红林.基于数字散斑相关法的岩石材料力学性能的测试[J].应用光学,2013,34(1):123-127.
[13]郭文婧,马少鹏,康永军,等.基于数字散斑相关方法的虚拟引伸计及其在岩石裂纹动态观测中的应用[J].岩土力学,2011,32(10):3196-3200.
[14]彭瑞东,翁炜,左建平,等.数字散斑相关法在SEM观测岩石变形时的应用[J].中国矿业大学学报,2012,41(4):650-656.
[15]宋义敏,马少鹏,杨小彬,等.岩石变形破坏的数字散斑相关方法研究[J].岩石力学与工程学报,2011,30(1):170-175.