岩石在冲击压缩破坏过程中的能量演化分析

Research on Rock Energy Evolution in the Process of Impact Compression Failure

从宏观热力学原理出发,分析岩石冲击压缩破坏过程中的能量演化过程,将作用于岩石系统的外部能量定义为输入能(ψ),内部自平衡能量分为可释放弹性应变能(ψe)和结构破坏能(ψd),通过岩石的SHPB试验分析各部分能量的变化,试验结果表明:岩石的冲击压缩过程实质上是岩石系统通过内部ψe和ψd与ψ的不断转化平衡的过程,当累积ψd达到某一极限时,发生冲击破坏,ψe转化为其他形式能量释放出来;岩石的破坏时间,ψ,ψe和ψd都与冲击速度密切相关,冲击速度越大破坏时间越短,ψ的累积总量、累积速度也越大;并且累积ψe的变化时间迟于累积ψ和ψd的变化时间,前者在100μs后开始迅速增加,而后两者分别在75μs和50μs后开始迅速增加;冲击压缩过程中破坏临界比也与冲击速度相关,并且破坏临界比增加越快,破坏后岩石的碎块尺度越小,碎块越多。

Based on macroscopic thermodynamics principle,the energy evolution in process of rock impact compression failure has been researched,the concepts of input energy(ψ),elastic strain energy released(ψe) and structure damage energy(ψd) are defined. The change of these energy was analyzed by the rock SHPB experiment,the result shows that the process of rock impact compression is actually an balancing process by the transform betweenψ,ψe and ψd,the destroy happens whenψd comes to the extremity and ψe releases. The rock destroy time,ψ,ψe andψd have close relationship with impact velocity,the destroy time is shorter when the amount ofψ is larger as the impact velocity is faster. The change moment of ψe is later than ψ and ψd,the change moment ofψe is 100 μs and those of ψ and ψd are 75 μs and 50 μs,respectively. The damage level in dynamic destruction process also have close relationship with impact velocity,and as the damage increase faster,the dynamic failure fragment size is smaller,the amount of failure fragment is larger.