软岩现场流变试验及非线性分数阶蠕变模型  

Research on field rheological test and nonlinear fractional derivative creep model of weak rock mass

作　　者：刘泉声[1,2] 罗慈友 彭星新 刘鹤 陈磊 潘玉丛 LIU Quansheng;LUO Ciyou;PENG Xingxin;LIU He;CHEN Lei;PAN Yucong(State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan 430071,China;Key Laboratory of Geotechnical and Structural Safety Engineering of Hubei Province,Wuhan University,Wuhan 430072,China;University of Chinese Academy of Science,Beijing 100049,China;4th Engineering Co.,Ltd.,China Railway 11th Bureau Group,Wuhan 430073,China)

机构地区：[1]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,湖北武汉430071 [2]武汉大学岩土与结构工程安全湖北重点实验室,湖北武汉430072 [3]中国科学院大学,北京100049 [4]中铁十一局集团第四工程有限公司,湖北武汉430073

出　　处：《煤炭学报》2020年第4期1348-1356,共9页Journal of China Coal Society

基　　金：国家重点基础研究发展计划(973)资助项目(2015CB058102);国家自然科学基金资助项目(51874275,41807250)。

摘　　要：软弱岩体的流变力学特性研究对于保证矿井软岩巷道围岩的稳定性具有重要的意义,有必要进行软弱岩体的现场流变试验及其本构模型的研究工作。首先进行了煤矿软岩巷道底板大体积软弱岩体的现场分级加载压缩蠕变试验,其后引入分数阶微积分理论,采用Abel黏壶元件替代传统Burgers流变模型中的粘弹性体(即Kelvin体),并基于现场岩体流变试验结果中岩体试样在加速蠕变阶段的变形特征,在改进后的Burgers模型上串联上非线性黏塑性体(即NAVPB),建立了现场软弱岩体的非线性分数阶蠕变模型,最后基于岩体试样的流变试验数据,进行了非线性分数阶蠕变模型和Burger模型的参数拟合与对比分析。软弱岩体现场流变试验结果表明:岩体试样是否发生加速蠕变与加载的应力水平有关,其蠕变存在加速蠕变应力阈值,应力不大于该阈值时,岩体试样蠕变只发生衰减蠕变阶段和稳定蠕变阶段,且稳定蠕变阶段变形速率不为零;应力大于该阈值时,岩体试样经历完整的衰减蠕变、稳定蠕变和加速蠕变3阶段并最终发生破坏,且存在加速蠕变启动时间点。模型参数拟合及对比结果表明:提出的软弱岩体非线性分数阶蠕变模型结构较为简单,相较于Burgers模型,能较好地描述现场软弱岩体包括加速蠕变阶段在内的全阶段蠕变特征。The study of rheological mechanical properties of weak rock mass is of great significance for ensuring the surrounding rock stability of soft rock roadway in mine.It is necessary to carry out the field rheological test on weak rock mass and the research on its constitutive model.The in-situ graded-loading creep test on large-volume weak rock mass samples in the soft rock roadway in a coal mine was carried out.The fractional derivative theory was introduced.The Abel viscous element was used to replace the viscoelastic body(Kelvin body)in the traditional Burgers rheological model.Based on the deformation characteristics of rock mass samples during the accelerated creep stage in the test results,the nonlinear visco-plastic body(NAVPB)was connected in series to the improved Burgers model to establish a nonlinear fractional derivative creep model of the field weak rock mass.Based on the creep test data of the rock mass samples,the parameter fitting and comparative analysis of the nonlinear fractional derivative creep model and the Burger model were performed.The field rheological experimental results of weak rock mass show that whether the rock mass samples undergo accelerated creep is related to the stress level of loading.There is a stress threshold of accelerated creep.When the stress is no more than the threshold,the rock mass sample only undergoes the decay creep stage and the stable creep stage,and the deformation rate in the stable creep stage is not zero.When the stress is greater than the threshold,the rock mass sample undergoes the complete decay creep,stable creep and accelerated creep three stages and fails finally.There is a startup point for the accelerated creep.Model parameter fitting and comparison results show that the structure of proposed nonlinear fractional creep model of weak rock mass is simpler.Compared with the Burgers model,the proposed model can describe the full-stage creep characteristics including the accelerated creep stage of field weak rock mass.The research results have a certain app

关 键 词：软弱岩体 现场流变试验 分数阶 非线性蠕变模型 

分 类 号：TD315[矿业工程—矿井建设]