深部砂岩动态冲击破坏的力学特性研究

Study on mechanical properties of dynamic impact failure of deep sandstone

为了研究深部砂岩在热-水-力耦合作用下的动力学特性,利用自主研发的热-水-力耦合三轴岩土体动态冲击力学试验系统,分析了动态冲击下深部砂岩的力学参数并从能量的角度描述其破坏形态。研究结果表明:在具有主动围压、轴压、渗透水压及温度的耦合作用下,冲击气压增大时,深部砂岩的应力-应变曲线的峰值应力随之增大;深部砂岩的峰值应力与应变率变化表现出明显的正相关性,具体表现为随着应变率的增大,峰值应力不断增大;随着冲击气压的增大,破碎程度不断加大,深部砂岩的破坏形态向压剪破坏过渡和发展,岩石试件的破坏形态呈脆性向延性转变的趋势。试验结果可以为深部砂岩在实际爆破工程中提供参数支撑。

In order to study the dynamic characteristics of deep sandstone under the thermal-hydraulic-mechanical coupling action,a self-developed thermo-hydro-mechanical coupling triaxial rock-soil dynamic impact test system was employed to analyze the mechanical parameters of deep sandstone under dynamic impact and describe its failure form from the perspective of energy.Experimental results show that under the coupling action of active confining pressure,axial pressure,osmotic pressure and temperature,the peak stress of stress-strain curve of deep sandstone increases with the increase of impact pressure.The peak stress of deep sandstone shows obvious positive correlation with the change of strain rate,characterized by the fact that the peak stress increases continuously with the increase of strain rate.With the increase of impact pressure,the destructive pattern of deep sandstone is dramatically building up,and developed to compression shear failure coupled with the growing degree of fracture,and the destructive pattern of rock specimen is transitioning from being brittle to being ductile.The test results can provide parameter support for deep sandstone in actual blasting engineering.