摘要
劈裂拉伸破坏是隧洞围岩失稳破坏的主要形式之一。现阶段,在动态劈裂条件下岩石裂纹扩展及对应阶段的能量演化机制鲜有涉及。基于此,采用分离式霍普金森压杆对锦屏大理岩试样进行了不同弹速下的劈裂试验,并借助ANSYS/LS-DYNA有限元软件,模拟试样动态劈裂破坏过程。从试验测试和数值计算角度,重点分析大理岩劈裂过程中的裂纹扩展机制以及能量演化特征。结果表明:在应变率为5~35s^(-1)时,大理岩的动态拉伸强度与应变率呈线性正相关,同其他地区大理岩相比较,锦屏大理岩的应变率敏感性相对较低;随着弹速的增加,系统内能和动能均增大,在试样破坏的瞬间系统内能降至最低;采用标定的Cowper-Symonds本构模型参数进行数值模拟,所得的试样最终破坏形态与试验观察到的现象基本一致。研究结果可为具体工程应用提供指导和参考。
Splitting tensile failure is one of the main forms of instability failure of tunnel surrounding rock.At present,the mechanisms of rock crack propagation and energy evolution at the corresponding stages under dynamic splitting conditions have been rarely addressed.In this study,the splitting tests were carried out on Jinping marble samples using a split-Hopkinson pressure bar under different striking velocities.The dynamic damage processes of the samples were simulated with the ANSYS/LS-DYNA finite element software.From the perspectives of loboratory tests and numerical calculations,the mechanism of crack propagation and the characteristics of energy evolution during the splitting process of marble were comprehensively analyzed.The results show that the dynamic tensile strength of marble is linearly and positively related to the strain rate in the range of 5 s^(-1)to 35 s^(-1).The strain rate sensitivity of the Jinping marble is relatively low compared with the marbles of other regions.With the increase of the striking velocity,both the internal energy and kinetic energy of the system increase.At the moment of sample failure,the internal energy of the system drops to a minimum.Based on the calibrated parameters of Cowper-Symonds constitutive model,the final failure modes of the numerically simulated samples are basically consistent with the observed ones in the experiments.The research results of this study can provide guidance and reference for specific engineering applications.
作者
缪逢晨
王志亮
孙盼
李松玉
傅晶晶
MIAO Fengchen;WANG Zhiiang;SUN Pan;LI Songyu;FU Jingjing(School of Civil and Hydraulic Engineering,Hefei University of Technology,Hefei,Anhui 230009,China)
出处
《水文地质工程地质》
CAS
CSCD
北大核心
2024年第2期155-162,共8页
Hydrogeology & Engineering Geology
基金
国家自然科学基金项目(U1965101,12272119)。
关键词
大理岩
应变率
裂纹扩展
能量特征
数值模拟
marble
strain rate
crack extension
energy characteristics
numerical simulation
