黔西南金矿砂岩动静组合加载岩石力学特性研究

Study on the Mechanical Properties of Sandstone Under Dynamic and Static Combined Loading in Gold Ore in Southwest Guizhou

为探究巷道开挖后围岩不同深度切向应力不同程度的增加对围岩动力学性能的影响,采用改进的分离式霍普金森压杆(split Hopkinson pressure bar,SHPB)试验系统,对黔西南金矿砂岩试件在0,10,20,30,40MPa的轴压下进行动静组合加载试验,旨在分析砂岩在不同轴压下的力学行为、变形特征与能量演化规律。研究发现:动静组合加载试样应力-应变曲线分为压密阶段、弹性阶段、塑性破坏和峰后阶段;轴压使得峰值应变逐渐增加,极限应变逐渐降低;动态弹性模量、动态抗压强度、应变率及各能量的演化规律均呈现以10MPa为转折点的变化规律。

In order to explore the influence of the increase of tangential stress at different depths of surrounding rock after roadway excavation,an improved split Hopkinson pressure bar(SHPB)test system was used to carry out dynamic and static combined loading tests on sandstone specimens of gold ore in southwest Guizhou under axial compression of 0,10,20,30 and 40 MPa,aiming to analyze the mechanical behavior,deformation characteristics and energy evolution law of sandstone under different axial compression.It is found that the stress-strain curve of the specimen under dynamic and static combined loading is divided into compaction stage,elastic stage,plastic failure stage and post-peak stage.Axial compression makes the peak strain increase gradually and the utimate strain decrease gradually.The dynamic elastic modulus,dynamic compressive strength,strain rate and the evolution of each energy all show the change rule with 10 MPa as the turning point.