岩石破坏的能量分析初探

从能量的角度出发,分析研究了岩石的变形破坏过程,揭示了这一过程的能量耗散及能量释放特性。理论及试验研究表明,在岩石变形破坏过程中,能量起着根本的作用。岩石的失稳破坏就是岩石中能量突然释放的结果,这种释放是能量耗散在一定条件下的突变。从力学角度而言,岩石的变形破坏过程实际上就是一个从局部耗散到局部破坏最终到整体灾变的过程;从热力学上看,这一变形、破坏、灾变过程是一种能量耗散的不可逆过程,包含能量耗散和能量释放。现有的力学理论体系主要是强调能量耗散结构和局部破坏过程,而岩石的灾变是以能量释放为其主要特征,所以有必要综合考虑能量耗散及能量释放对岩石变形破坏的影响。试验研究也揭示了应力–应变强度不能很好地描述岩石的破坏这一特性,在大体相同的应力–应变曲线下,试件的破坏形式不同,能量释放量完全不同,因此,从能量的观点可以更好地描述岩石的变形破坏。

ON ENERGY ANALYSIS OF ROCK FAILURE

On the viewpoint of energy,the deformation and failure process of rock are studied. The behavior of energy dissipation and energy release during this process is also discussed. Theoretical and laboratory experimental studies indicate that energy plays an important role during rock deformation and failure. Rock failure is caused by the abrupt energy release,which is the catastrophe of energy dissipation under a certain condition. From the viewpoint of mechanics,rock deformation and failure process are processes from local dissipation to part failure and eventually to whole catastrophe;in addition,from the viewpoint of thermodynamics,this process is an irreversible process which includes energy dissipation and energy release. Current mechanics theories emphasize the energy dissipation and part breakage,however,the main feature of rock failure is energy release. Therefore, it is necessary to consider synthetically the effect of energy dissipation and energy release. Laboratory studies in the paper also demonstrate that the rock failure feature can not be described by the stress or strain strength. It is observed that the failure types of rock samples are different from each other even if the stress-strain curves are almost uniform,but the amount of energy release of rock samples is distinct. Consequently,the rock deformation and fracture process can be well described from the viewpoint of energy.