冻融循环作用下尾矿坝的力学响应特征
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摘要
寒区冻融环境条件下,尾矿砂的冻融、缩胀、损伤破坏给寒区尾矿坝工程造成极大的危害。为探究冻融循环作用下尾矿坝变形规律,揭示其变形机制。采用自主设计的尾矿坝相似模型试验装置,开展不同冻结温度(-5、-25、-45℃)条件下,尾矿坝的变形规律模型试验。借助土压力、激光位移、孔隙水压力传感器,采用动态数据采集仪采集相关数据,分析冻融循环过程中尾矿坝各关键位置应力、变形、孔隙水压力的动态变化规律。试验结果表明:坝体内应力随冻结温度的降低而增大,在冻融循环前期,尾矿坝各关键位置应力增长速度明显高于冻融循环其他阶段。坝体内孔隙水压力随冻结温度的降低而减小,坝体越深,孔隙水压力的变化幅度越大,周期性更强,也更具有规律性。冻结温度具有明显的位置效应,越靠近尾矿坝边缘,坝体变形量越大,变形速度越快。
The freezing and thawing,shrinkage and expansion,and damage of tailings sand can cause great harm to the project of tailing dam in cold regions.In order to explore the deformation characteristics of tailing dam and reveal its deformation mechanism under freeze-thawing,down-scale tailings dam model tests were carried out on a self-designed device under different freezing temperatures(-5,-25,-45℃).The soil pressure,displacement and pore water pressure at each key position of tailing dam during the freeze-thaw cycle were measured by the dynamic data acquisition instrument.The test results show that:the internal stress of the dam increases with decrease of freezing temperature;the stress growth rate in the early stage of freeze-thaw cycleat each key position is higher than that at the other stages.The pore water pressure in the dam decreases with decrease of freezing temperature.The variation range,periodicity and regularity of pore pressure increases with the position depth of the dam.Besides,it is revealed that the freezing temperature has obvious position effect.The closer to the tailings dam edge,the greater the deformation magnifude of dam body and the higher of the deformation rate.
The freezing and thawing,shrinkage and expansion,and damage of tailings sand can cause great harm to the project of tailing dam in cold regions.In order to explore the deformation characteristics of tailing dam and reveal its deformation mechanism under freeze-thawing,down-scale tailings dam model tests were carried out on a self-designed device under different freezing temperatures(-5,-25,-45℃).The soil pressure,displacement and pore water pressure at each key position of tailing dam during the freeze-thaw cycle were measured by the dynamic data acquisition instrument.The test results show that:the internal stress of the dam increases with decrease of freezing temperature;the stress growth rate in the early stage of freeze-thaw cycleat each key position is higher than that at the other stages.The pore water pressure in the dam decreases with decrease of freezing temperature.The variation range,periodicity and regularity of pore pressure increases with the position depth of the dam.Besides,it is revealed that the freezing temperature has obvious position effect.The closer to the tailings dam edge,the greater the deformation magnifude of dam body and the higher of the deformation rate.
引文
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[15]单仁亮,黄博,郑赟,等.竖向动载下巷道支护相似模拟试验装置的研制[J].岩土工程学报,2019,41(2):294-302.SHAN R L,HUANG B,ZHENG Y,et al.Development of similar simulation test device for roadway support under vertical dynamic load[J].Chinese Journal of Geotechnical Engineering,2019,41(2):294-302.(in Chinese)
[16]黄庆享,胡火明.黏土隔水层的应力应变全程相似模拟材料和配比实验研究[J].采矿与安全工程学报,2017,34(6):1174-1178.HUANG Q X,HU H M.Experimental study of simulation material and matching for whole stress and strain process of clay aquiclude[J].Journal of Mining and Safety Engineering,2017,34(6):1174-1178.(in Chinese)
[17]土工试验方法标准:GB/T 50123-1999[S].北京:中国计划出版社,1999.Geotechnical test method standard:GB/T 50123-1999[S].Beijing:China Planning Press,1999.(in Chinese)
[18]DEMIRDAG S.Effects of freezing-thawing and thermal shock cycles on physical and mechanical properties of filled and unfilled travertines[J].Construction and Building Materials,2013,47:1395-1401.
[19]魏作安,杨永浩,徐佳俊,等.人工冻结尾矿力学特性单轴压缩试验研究[J].东北大学学报(自然科学版),2016,37(1):123-126,142.WEI Z A,YANG Y H,XU J J,et al.Experimental study on the mechanical properties of frozen tailings by uniaxial compression tests[J].Journal of Northeastern University(Natural Science),2016,37(1):123-126,142.(in Chinese)
[2]AUKENTHALER M,BRINKGREVE R B J,HAXAIRE A.Evaluation and application of a constitutive model for frozen and unfrozen soil[C]//Proceedings of the GeoVancouver 2016:the 69th Canadian Geotechnical Conference,Vancouver,Canada,2016:1-8.
[3]YAMAMOTO Y,SPRINGMAN S M.Axial compression stress path tests on artificial frozen soil samples in a triaxial device at temperatures just below0℃[J].Canadian Geotechnical Journal,2014,51(10):1178-1195.
[4]NIU G Y.Representing frozen soil and its effect on infiltration in Earth System Models[C]//AGU Fall Meeting Abstracts,2015:1-5.
[5]张志军,李亚俊,贺桂成,等.某尾矿坝毛细水带内的坝体材料物理力学特性研究[J].岩土力学,2014,35(6):1561-1568.ZHANG Z J,LI Y J,HE G C,et al.Study of physicomechanical properties of dam body materials in capillary water fringe of a certain tailings dam[J].Rock and Soil Mechanics,2014,35(6):1561-1568.(in Chinese)
[6]黄鑫,蔡晓光.中线法尾矿砂的物理力学性质试验研究[J].防灾减灾工程学报,2016,36(2):220-224,238.HUANG X,CAI X G.Experimental study on physical and mechanical properties of central line tailing sands[J].Journal of Disaster Prevention and Mitigation Engineering,2016,36(2):220-224,238.(in Chinese)
[7]GHOBADI M H,TORABI-KAVEH M.Assessing the potential for deterioration of limestones forming Taq-e Bostan monuments under freeze-thaw weathering and karst development[J].Environmental Earth Sciences,2014,72(12):5035-5047.
[8]于广明,宋传旺,潘永战,等.尾矿坝安全研究的国外新进展及我国的现状和发展态势[J].岩石力学与工程学报,2014,33(Sup1):3238-3248.YU G M,SONG C W,PAN Y Z,et al.Review of new progress in tailing dam safety in foreign research and current state with development trent in China[J].Chinese Journal of Rock Mechanics and Engineering,2014,33(Sup1):3238-3248.(in Chinese)
[9]明锋,李东庆,陈世杰,等.水分迁移对冻土细观结构的影响[J].冰川冻土,2016,38(3):671-678.MING F,LI D Q,CHEN S J,et al.Impact of water migration on meso-structure of frozen soil[J].Journal of Glaciology and Geocryology,2016,38(3):671-678.(in Chinese)
[10]李清,席军,宛新林,等.冻融和循环载荷作用下对饱和砂岩损伤机理的研究[J].实验力学,2014,29(4):520-526.LI Q,XI J,WAN X L,et al.Research on damage mechanism of saturated sandstone subjected to freezethaw and cyclic loading[J].Journal of Experimental Mechanics,2014,29(4):520-526.(in Chinese)
[11]BEIER N A,SEGO D C.Cyclic freeze-thaw to enhance the stability of coal tailings[J].Cold Regions Science and Technology,2009,55(3):278-285.
[12]ZANDARíN M T,OLDECOP L A,RODRíGUEZ R,et al.The role of capillary water in the stability of tailing dams[J].Engineering Geology,2009,105(1/2):108-118.
[13]张二军,梁冰,王彪,等.冻融循环作用下尾矿砂抗剪强度和变形特性研究[J].安全与环境学报,2018,18(1):134-138.ZHANG E J,LIANG B,WANG B,et al..Deformation behaviors of the tailing sands under the shear strength and freezing-thawing recycling impact[J].Journal of Safety and Environment,2018,18(1):134-138.(in Chinese)
[14]彭成,谌伟,陈双,等.细粒砂尾矿坝渗透试验及有限元分析[J].现代矿业,2016,32(11):185-187.PENG C,CHEN W,CHEN S,et al.Seepage test and finite element analysis of fine grained milltailings of tailings dam[J].Modern Mining,2016,32(11):185-187.(in Chinese)
[15]单仁亮,黄博,郑赟,等.竖向动载下巷道支护相似模拟试验装置的研制[J].岩土工程学报,2019,41(2):294-302.SHAN R L,HUANG B,ZHENG Y,et al.Development of similar simulation test device for roadway support under vertical dynamic load[J].Chinese Journal of Geotechnical Engineering,2019,41(2):294-302.(in Chinese)
[16]黄庆享,胡火明.黏土隔水层的应力应变全程相似模拟材料和配比实验研究[J].采矿与安全工程学报,2017,34(6):1174-1178.HUANG Q X,HU H M.Experimental study of simulation material and matching for whole stress and strain process of clay aquiclude[J].Journal of Mining and Safety Engineering,2017,34(6):1174-1178.(in Chinese)
[17]土工试验方法标准:GB/T 50123-1999[S].北京:中国计划出版社,1999.Geotechnical test method standard:GB/T 50123-1999[S].Beijing:China Planning Press,1999.(in Chinese)
[18]DEMIRDAG S.Effects of freezing-thawing and thermal shock cycles on physical and mechanical properties of filled and unfilled travertines[J].Construction and Building Materials,2013,47:1395-1401.
[19]魏作安,杨永浩,徐佳俊,等.人工冻结尾矿力学特性单轴压缩试验研究[J].东北大学学报(自然科学版),2016,37(1):123-126,142.WEI Z A,YANG Y H,XU J J,et al.Experimental study on the mechanical properties of frozen tailings by uniaxial compression tests[J].Journal of Northeastern University(Natural Science),2016,37(1):123-126,142.(in Chinese)