不同应变率下砂岩的动态力学特性研究

Research into the dynamic mechanical characteristics of sandstone under different strain rate

矿山等地下硐室施工通常采用工程爆破的方式进行开挖,在工程爆破等动力荷载作用下岩石存在动力硬化现象。利用分离式霍普金森压杆装置对砂岩岩样进行了5组不同应变率下的冲击试验,在此基础上系统分析了入射波、反射波和透射波等试验数据,绘制出动态抗压强度与应变率的散点关系图、峰值应变与应变率的散点关系图、动态应力-应变曲线图,并得到砂岩在不同应变率下的动力硬化因数,分析了砂岩在不同应变率下的动态力学特性及动态抗压强度与应变率的关系,并对不同应变率下岩石样本的破坏形态进行了归纳分析。

Underground cavities in mine usually adopt the engineering blasting method to conduct the excavation,the rock material would show the hardening phenomenon under the dynamic loading,such as engineering blasting.By taking the Split Hopkinson Pressure Bar system,a dynamic impact test with 5groups of sandstone samples under different strain rate were conducted,after that,the data of incident wave,reflected wave and transmitted wave could be analysed.So,the dynamic compressive strength with strain rate,the peak strain with strain rate and dynamic stress-strain curve were drawn.And the dynamic harden factor under different strain rate was obtained.At last,the analysis on dynamic mechanical properties of the sandstone and the relationship between dynamic compressive strength and strain rate were carried out,and failure mode of the rock samples with different strain rate was summarized.