• 论文
主办单位:煤炭科学研究总院有限公司、中国煤炭学会学术期刊工作委员会
循环荷载下粉砂岩孔裂隙扩展及卸载破坏特征
  • Title

    Pore fracture propagation and unloading failure characteristics of siltite under cyclic loads

  • 作者

    刘向御柴肇云刘绪杨泽前辛子朋

  • Author

    LIU Xiangyu,CHAI Zhaoyun,LIU Xu,YANG Zeqian,XIN Zipeng

  • 单位

    太原理工大学 矿业工程学院太原理工大学 原位改性采矿教育部重点实验室

  • Organization
    College of Mining Engineering,Taiyuan University of Technology;Key Laboratory of In⁃Situ Property⁃Improving Mining of Ministry of Education,Taiyuan University of Technology.
  • 摘要

    为揭示循环荷载下地下工程围岩体孔裂隙扩展及破坏机制借助于单轴压缩和 CT 扫描, 开展了粉砂岩的等幅循环逐级一次循环加卸载试验。 研究了循环荷载下粉砂岩应力-应变曲线、 孔裂隙扩展及破坏阶段裂缝产状规模等演化规律。 结果表明:种循环荷载作用下粉砂岩孔隙 率均呈先减小后增加的总趋势且致裂循环的孔隙率均发生突变具有瞬时破裂特征;等幅循环加 卸载下岩石破坏发生在第 25 次循环加载段主要依据应变差累积应变差及其一阶导数将岩样破 坏段裂缝扩展细分为裂缝萌生裂缝扩展和加速破坏等 个阶段;逐级一次循环加卸载下岩石破 坏发生在第 次循环卸载强度低于峰值载荷 1.04 MPa 呈现出小幅振荡破坏特征主要依据单 峰波动应力振幅频率应变差累积应变差及其一阶导数将岩样破坏段裂缝扩展细分为裂缝萌生、 裂缝快速扩展裂缝扩展亚稳态裂缝再生和加速破坏等 个阶段。 按应力-应变曲线形态小幅 振荡破坏可细分为往复式滞回环式波动应力振幅波动频率特征分析可见清晰的应力调整过程。 岩样原始孔裂隙分布状态对其致裂部位及破坏形式起主控作用。 种循环荷载作用下岩样破裂 均以剪切破裂为主并次生了张性破裂。 卸载段回弹和扩容效应是出现小幅振荡破坏的主要原因


  • Abstract

    In order to reveal the pore fracture propagation and failure mechanism of underground engineering surround⁃ ing rock under cyclic loads,the uniaxial compression and CT scanning were used to carry out constant amplitude cyclic loading and unloading and stepwise linear cyclic loading and unloading tests on siltite. The stress⁃strain curves of siltite,the propagation of pores and fractures,and the occurrence and scale of fractures in the failure stage are studied under cyclic loading and unloading. The results show that the siltite porosity decreases first and then increases under two kinds of cyclic loads,and the porosity of fracture cycle changes suddenly,which has the characteristics of in⁃ stantaneous fracture. Under the constant amplitude cyclic loading and unloading,rock failure occurs in the 25th cyclic loading section, and according to the strain difference, the cumulative strain difference and its first derivative mainly,the fracture propagation in the failure stage of rock samples is subdivided into three stages: fracture initiation, fracture propagation,and accelerated failure. Under the stepwise lineal cyclic loading and unloading,the rock failure occurs in the 4th cyclic unloading section,and presents the characteristics of low⁃amplitude oscillation failure when the strength is lower than the peak load of 1.04 MPa. According to the unimodal fluctuant stress amplitude,frequency, strain difference,cumulative strain difference and its first derivative mainly,the fracture propagation in the failure stage of rock samples is subdivided into five stages: fracture initiation,rapid fracture propagation,metastable fracture propa⁃ gation,fracture regeneration,and accelerated failure. According to the form of stress⁃strain curve,the low⁃amplitude os⁃ cillation failure can be subdivided into a reciprocating cyclic wave and a hysteretic cyclic wave,and the analysis of stress amplitude and wave frequency shows a clear stress adjustment process. The distribution of original pores and fractures of the rock samples plays a major role in controlling the fracture location and failure form. Under the action of two kinds of cyclic loads,the fracture of rock samples is mainly shear fracture and secondary tensile fracture. The rebound and dilatancy effect of the unloading section are the main causes of low⁃amplitude oscillation failure.



  • 关键词

    循环加卸载粉砂岩孔裂隙扩展规律小幅振荡破坏阶段

  • KeyWords

    cyclic loading and unloading;siltite;pore fracture;propagation law;low⁃amplitude oscillation;failure stage

  • 引用格式
    刘向御,柴肇云,刘绪,等. 循环荷载下粉砂岩孔裂隙扩展及卸载破坏特征[J].煤炭学报,2022,47(S1):77-89.
  • Citation
    LIU Xiangyu,CHAI Zhaoyun,LIU Xu,et al. Pore fracture propagation and unloading failure characteristics of sil⁃ tite under cyclic loads[J]. Journal of China Coal Society,2022,47(S1):77-89.
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