白云岩三维动静组合加载力学特性试验研究

为研究白云岩的力学特性和破坏模式，利用改进的三维SHPB动静组合加载试验装置，对白云岩进行三维加载、轴向冲击试验，分析轴压、围压和应变率对白云岩强度、变形模量、能量吸收等的影响，探讨岩石动静组合加载的应变率效应。试验结果表明：当围压一定时，白云岩的抗压强度随着轴压的增大呈现出先增大后减小的趋势，变形模量随着轴压的增大而减小；白云岩单位体积吸收能会随着轴压的增大而先增加后降低。轴压固定时，白云岩的抗压强度和变形模量随着围压的增加而增大，白云岩强度增长因子有显著的应变率效应；白云岩单位体积吸收能会随着围压的增大先升高而后降低，随平均应变率的增大而增大。在三维动静组合加载下，岩石的破坏模式为压剪破坏。

Experimental study on mechanical characteristics of dolomite under three-dimensional coupled static-dynamic loading

This paper investigates the mechanical characteristics and failure modes of dolomite.The dynamic triaxial compression tests of dolomite specimens under three-dimensional loading and axial impact were conducted by using the modified three-dimensional split Hopkinson pressure bar (SHPB) apparatus.The influence of axial pressure，confining pressure and strain rate on strength，deformation modulus and energy absorption of dolomite was analyzed.The strain rate effect of the coupled static-dynamic loading of rock was discussed.The test results show that：when the confining pressure is constant and the axial static pressure increases，the compressive strength of rock increases at first and then decreases while the deformation modulus decreases；the energy absorption per unit volume first increases and then decreases with the increasing of axial pressure.When the axial pressure of dolomite specimens is fixed，the compressive strength and deformation modulus increases with the increasing confining pressure.The strength increase factor of dolomite has a significant strain rate effect；the energy absorption per unit volume will first increase and then decrease with the increase of confining pressure，but it increases with the increasing average strain rate.The failure pattern of dolomite is compression-shear under three-dimensional coupled dynamic and static loading.