露天矿高陡边坡软岩蠕变-大变形试验及本构模型  

Creep-large deformation experiment and constitutive model of soft rock in high and steep slope of open-pit

作　　者：缪海宾 MIAO Haibin(China Coal Technology and Engineering Group Shenyang Research Institute,Fushun 113122,China;State Key Laboratory of Coal Mine Safety Technology,Fushun 113122,China)

机构地区：[1]中煤科工集团沈阳研究院有限公司,辽宁抚顺113122 [2]煤矿安全技术国家重点实验室,辽宁抚顺113122

出　　处：《煤矿安全》2022年第1期94-99,共6页Safety in Coal Mines

基　　金：国家重点研发计划资助项目(2017YFC1503101);中煤科工集团科技创新基金资助项目(2019-QN002)。

摘　　要：为探寻露天矿高陡边坡软岩蠕变-大变形规律,开展了软岩常规压缩、峰值前压缩蠕变和峰值后压缩蠕变等试验。试验结果显示:软岩常规应力-应变曲线表现出了明显的弹脆塑性向弹塑性转化的趋势,由于软岩的强度较低,该现象更加明显;软岩蠕应变对围压的敏感度较高,峰值前低围压时弱层软岩的蠕应变由2.5%增大到14.5%,说明软岩在低围压、高应力作用下具有典型的大变形特征;峰值后弱层软岩的蠕应变变化较小,说明其峰值后蠕变特性不稳定;峰值前的黏滞系数受围压的影响大,随着围压的增大,K体与M体的黏滞系数逐渐减小;围压对峰值后的黏滞系数影响较小,但对K体黏滞系数影响的要较M体的大,软岩会由弹性阶段向塑性阶段转化。在试验研究的基础上,建立了软岩BNSS蠕变-大变形本构模型。For the sake of exploring the law of creep-large deformation of soft rock under high and steep slope in open-pit mine,conventional compression,pre-peak compression creep and post-peak compression creep experiments of soft rock were carried out.The results showed that:the conventional stress-strain curve of soft rock illustrates a clear tendency to transform from elasticbrittle plasticity to elastic-plastic plasticity.This phenomenon is more obvious due to the lower strength of soft rock;soft rock creep strain is more sensitive to confining pressure,which increases from 2.5%to 14.5%at low confining pressure before peak,which indicates that soft rock has typical large deformation characteristics under low confining pressure and high stress;the creep strain of weak soft rock has less change after peak,which indicates that the creep characteristics are unstable in this time;the viscosity coefficient before peak is greatly affected by the confining pressure.As the confining pressure increases,the viscosity coefficients of K-body and M-body gradually decrease;the confining pressure has little effect on the viscosity coefficient after the peak.However,the influence of the K-body viscosity coefficient is greater than that of the M-body,and soft rock with elastic stage will transform to plastic stage.Based on the experimental research,the BNSS creep-large deformation constitutive model of soft rock was established.

关 键 词：高陡边坡 弱层软岩 三轴压缩试验 蠕变-大变形 本构模型 

分 类 号：TD315[矿业工程—矿井建设]