基于膏体稳定系数的级配表征及屈服应力预测
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摘要
由于不同矿山充填材料性质千差万别,屈服应力影响因素很难统一分析.通过多个矿山尾砂试样,依次开展了级配表征及影响实验、相似密度流变实验以及基于体积分数和灰砂比的双因素流变实验,并结合细观图像分析技术,实现了屈服应力演化机理的研究.研究表明:膏体稳定系数是级配的有效表征方式,能够表现散体和流体综合特征;屈服应力随膏体稳定系数呈幂指数增长,随浓度呈指数型增长,随密度呈负指数增长,由此构建的全尾砂膏体屈服应力预测模型误差在10%以内;细观图像分析认为屈服应力主要受级配结构和絮网结构支配,级配结构构成了料浆可塑性和稳定性的基础,絮网结构将自由水转变为半稳定形态的吸附水,引起屈服应力宏观演化.
Paste backfilling has become an important support technology in green mining construction. The flowability and rheology performance of paste determine whether the slurry can be transported normally. As such,the evaluation of flowability and rheology of paste are important factors in the reliability of paste transportation. Because paste has the three characteristics of fluidity,stability and plasticity,traditional two-phase flow theory cannot effectively analyze its plug flow. However,it is an effective method for analyzing and evaluating the fluidity of the paste based on rheology theory,and the yield stress is an important parameter for evaluating the rheological characteristics of paste. Due to the different properties of the materials in different mines,it is difficult to analyze the factors that influence yield stress. Several experiments have been conducted on a variety of tailings from different mines,including a gradation characterization and influence experiment,a rheology experiment on materials of similar densities,and double-factor rheological experiments based on the concentration and sand ratio. Combined with mesoscopic structure analysis technology,the evolution mechanism of yield stress was studied. The results indicate that the stability coefficient of paste can effectively reflect the gradation,and can also reflect the comprehensive characteristics of the granule and fluid. The yield stress increases significantly with the paste stability coefficient and increases exponentially with the concentration. At the same time,yield stress is characterized by negative exponential growth with density. The error range of this yield stress prediction model for unclassified tailings paste is within 10%. The mesoscopic structure analysis shows that yield stress is mainly controlled by gradation and flocculent structure. The gradation constitutes the foundation for the plasticity and stability of the slurry. The flocculent structure transforms free water into the semi-stable form of adsorptive water,which causes the macro-evolution of the yield stress.
Paste backfilling has become an important support technology in green mining construction. The flowability and rheology performance of paste determine whether the slurry can be transported normally. As such,the evaluation of flowability and rheology of paste are important factors in the reliability of paste transportation. Because paste has the three characteristics of fluidity,stability and plasticity,traditional two-phase flow theory cannot effectively analyze its plug flow. However,it is an effective method for analyzing and evaluating the fluidity of the paste based on rheology theory,and the yield stress is an important parameter for evaluating the rheological characteristics of paste. Due to the different properties of the materials in different mines,it is difficult to analyze the factors that influence yield stress. Several experiments have been conducted on a variety of tailings from different mines,including a gradation characterization and influence experiment,a rheology experiment on materials of similar densities,and double-factor rheological experiments based on the concentration and sand ratio. Combined with mesoscopic structure analysis technology,the evolution mechanism of yield stress was studied. The results indicate that the stability coefficient of paste can effectively reflect the gradation,and can also reflect the comprehensive characteristics of the granule and fluid. The yield stress increases significantly with the paste stability coefficient and increases exponentially with the concentration. At the same time,yield stress is characterized by negative exponential growth with density. The error range of this yield stress prediction model for unclassified tailings paste is within 10%. The mesoscopic structure analysis shows that yield stress is mainly controlled by gradation and flocculent structure. The gradation constitutes the foundation for the plasticity and stability of the slurry. The flocculent structure transforms free water into the semi-stable form of adsorptive water,which causes the macro-evolution of the yield stress.
引文
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[18]Yan H,Zhang J X,Zhang S,et al.Macro-micro research on compaction properties of granular backfilling materials.J China Coal Soc,2017,42(2):413(闫浩,张吉雄,张升,等.散体充填材料压实力学特性的宏细观研究.煤炭学报,2017,42(2):413)
[19]Zhang L W,Zhang J M,Zhang G.Microfabric analysis technique for granular materials based on digital images.Chin J Geotech Eng,2008,30(10):1555(张连卫,张建民,张嘎.基于数字图像的粒状材料细观组构特征分析技术.岩土工程学报,2008,30(10):1555)
[20]Wu A X,Ai C M,Wang Y M,et al.Test and mechanism analysis on improving rheological property of paste with pumping agent.J Cent South Univ Sci Technol,2016,47(8):2752(吴爱祥,艾纯明,王贻明,等.泵送剂改善膏体流变性能试验及机理分析.中南大学学报(自然科学版),2016,47(8):2752)
[21]Liu G Q.Discrete Element Methods of Fine Particle Dynamics in Presence of van der Waals and Electrostatic Forces[Dissertation].Beijing:Tsinghua University,2011(柳冠青.范德华力和静电力下的细颗粒离散动力学研究[学位论文].北京:清华大学,2011)
[22]Wu A X,Liu X H,Wang H J,et al.Microstructural evolution characteristics of an unclassified tailing paste in constant shearing.Chin J Eng,2015,37(2):145(吴爱祥,刘晓辉,王洪江,等.恒定剪切作用下全尾膏体微观结构演化特征.工程科学学报,2015,37(2):145)
[2]He M Z,Wang Y M,Forssberg E.Slurry rheology in wet ultrafine grinding of industrial minerals:a review.Powder Technol,2004,147(1-3):94
[3]Zhai Y G,Wu A X,Wang H J,et al.Threshold mass fraction of unclassified-tailings paste for backfill mining.J Univ Sci Technol Beijing,2011,33(7):795(翟永刚,吴爱祥,王洪江,等.全尾砂膏体充填临界质量分数.北京科技大学学报,2011,33(7):795)
[4]Liu X H,Wu A X,Wang H J,et al.Influence mechanism and calculation model of CPB rheological parameters.Chin J Eng,2017,39(2):190(刘晓辉,吴爱祥,王洪江,等.膏体流变参数影响机制及计算模型.工程科学学报,2017,39(2):190)
[5]Zhang X X,Qiao D P.Rheological property and yield stress forecasting model of high-density slurry with waste rock-tailings.J Saf Environ,2015,15(4):278(张修香,乔登攀.废石--尾砂高浓度料浆的流变特性及屈服应力预测模型.安全与环境学报,2015,15(4):278)
[6]Wu A X,Jiao H Z,Wang H J,et al.Yield stress measurements and optimization of Paste tailings.J Cent South Univ Sci Technol,2013,44(8):3370(吴爱祥,焦华喆,王洪江,等.膏体尾矿屈服应力检测及其优化.中南大学学报(自然科学版),2013,44(8):3370)
[7]Li L,Zhang J,Ferri H,et al.Slump tests for yield stress of paste tailings.Met Mine,2017(1):30(李亮,张柬,Hassani Ferri,等.膏体尾矿屈服应力的塌落度试验研究.金属矿山,2017(1):30)
[8]Guo Y B,Xu D.Testing method on rheological factors of tailings paste.J Taiyuan Univ Sci Technol,2015,36(5):396(郭亚兵,徐鼎.尾矿膏体流变学参数试验方法.太原科技大学学报,2015,36(5):396)
[9]Wu A X,Cheng H Y,Wang Y M,et al.Transport resistance characteristic of paste pipeline considering effect of wall slip.Chin J Nonferrous Met,2016,26(1):180(吴爱祥,程海勇,王贻明,等.考虑管壁滑移效应膏体管道的输送阻力特性.中国有色金属学报,2016,26(1):180)
[10]Ma K L,Long G C,Xie Y J,et al.Rheological properties of compound pastes with cement-fly ash-limestone powder.J Chin Ceram Soc,2013,41(5):582(马昆林,龙广成,谢友均,等.水泥--粉煤灰--石灰石粉复合浆体的流变性能.硅酸盐学报,2013,41(5):582)
[11]Wang Y,Wu A X,Wang H J,et al.Further development of paste definition from the viewpoint of yield tress.J Univ Sci Technol Beijing,2014,36(7):855(王勇,吴爱祥,王洪江,等.从屈服应力角度完善膏体定义.北京科技大学学报,2014,36(7):855)
[12]Liu Q S,Lu C B,Liu B,et al.Research on rheological behavior for cement grout considering temperature and hydration time effects.Chin J Rock Mech Eng,2014,33(Suppl 2):3730(刘泉声,卢超波,刘滨,等.考虑温度及水化时间效应的水泥浆液流变特性研究.岩石力学与工程学报,2014,33(增刊2):3730)
[13]Cai S J,Huang G,Wu D,et al.Experimental and modeling study on the rheological properties of tailings backfill.J Northeast Univ Nat Sci,2015,36(6):882(蔡嗣经,黄刚,吴迪,等.尾砂充填料浆流变性能模型与试验研究.东北大学学报(自然科学版),2015,36(6):882)
[14]Ke X,Hou H B,Zhou M,et al.Effect of particle gradation on properties of fresh and hardened cemented paste backfill.Constr Build Mater,2015,96:378
[15]Chen B W,Mei F D,Yang L,et al.Research on gradation of coarse phosphate tailings cemented paste backfill and rule of workability of slurry.Sci Technol Eng,2015,15(13):25(陈博文,梅甫定,杨柳,等.粗磷尾矿胶结充填级配及料浆和易性规律研究.科学技术与工程,2015,15(13):25)
[16]Zhang J B,An X H,Nie D.Effect of fine aggregate characteristics on the thresholds of self-compacting paste rheological properties.Constr Build Mater,2016,116:355
[17]Qiu Y Q,Liu C S.Study of the size of particles and the composttion of sediment in high concentration slurry pipeline transportation.J Guizhou Univ Technol,1998,27(3):58(邱跃琴,刘春生.管道输送高浓度工业浆体的粒径与级配的探讨.贵州工业大学学报,1998,27(3):58)
[18]Yan H,Zhang J X,Zhang S,et al.Macro-micro research on compaction properties of granular backfilling materials.J China Coal Soc,2017,42(2):413(闫浩,张吉雄,张升,等.散体充填材料压实力学特性的宏细观研究.煤炭学报,2017,42(2):413)
[19]Zhang L W,Zhang J M,Zhang G.Microfabric analysis technique for granular materials based on digital images.Chin J Geotech Eng,2008,30(10):1555(张连卫,张建民,张嘎.基于数字图像的粒状材料细观组构特征分析技术.岩土工程学报,2008,30(10):1555)
[20]Wu A X,Ai C M,Wang Y M,et al.Test and mechanism analysis on improving rheological property of paste with pumping agent.J Cent South Univ Sci Technol,2016,47(8):2752(吴爱祥,艾纯明,王贻明,等.泵送剂改善膏体流变性能试验及机理分析.中南大学学报(自然科学版),2016,47(8):2752)
[21]Liu G Q.Discrete Element Methods of Fine Particle Dynamics in Presence of van der Waals and Electrostatic Forces[Dissertation].Beijing:Tsinghua University,2011(柳冠青.范德华力和静电力下的细颗粒离散动力学研究[学位论文].北京:清华大学,2011)
[22]Wu A X,Liu X H,Wang H J,et al.Microstructural evolution characteristics of an unclassified tailing paste in constant shearing.Chin J Eng,2015,37(2):145(吴爱祥,刘晓辉,王洪江,等.恒定剪切作用下全尾膏体微观结构演化特征.工程科学学报,2015,37(2):145)