循环载荷作用下岩石材料变形场演化试验研究

 将岩石在动载荷作用下破坏过程的应力场直观地表现出来，从变形场演化的角度研究岩石试件的破坏规律是岩石力学变形观测领域一个有重要意义的课题。采用岩石材料破坏过程变形场监测(Geo-DSCM)系统，观测循环载荷作用下岩石材料破坏过程中的变形场演化。岩石试件采用大理岩加工而成，对岩石试件加载的循环载荷为正弦波，其下、上限载荷分别为10，130 kN，频率为0.04 Hz。通过对多个岩石试件的变形破坏过程的观测，从变形场演化的角度总结岩石材料在循环载荷下的破坏规律。试验结果表明：循环载荷作用下岩石的变形经历3个阶段，即均匀阶段、局部化阶段和破坏阶段。岩石在破坏过程中其变形场演化表现出一个规律，即在破坏前夕发生严重的变形局部化现象，形成变形局部化带；变形局部化带中的变形进一步集中，形成宏观裂纹，导致试件破坏。从而可用一种描述变形场局部化特征的统计量(如变形场的方差)来表征变形场演化过程，岩石破坏前发生变形局部化，此统计量会发生突跳。因此，此统计量可用以指示岩石结构的破坏，如果设计现场观测系统，应用此方法有望实现灾害监测与预报。

TEST STUDY ON DEFORMATION FIELD EVOLUTION OF ROCK MATERIAL UNDER CYCLIC LOAD

Study of the failure law of rock using deformation field evolvement methord is a significant project in rock mechanics deformation observation field,and it can put up the stress field of rock material intuitively during process of destruction. By using the deformation field monitoring system(GEO-Dscm system),the deformation field evolvement has been observed in the failure procedure of rock material under cyclic load. The rock specimens are manufactured by marble plate,the cyclic loading is sine wave,with lower limit load and upper limit load are 10,130 kN respectively,the frequency is 0.04 Hz. The failure laws of rock material under cyclic loading are summarized according to the obersvation results of deformation failure process of multiple rock speciments. It is shown that the deformation of rock under cyclic loading experienced three stages:steady stage,localization stage and wreck stage. A law of deformation field evolution is shown that the severe deformation localization is occurred before rock failure and the deformation localization zone is formed. Along with the deformation concentration of localization zone,the macrocracks are occurred and the rock specimen is destroyed. Thus,a statistic which is used to describe the localization characteristic can indicate the process of deformation field evolvement. It will suddenly jump when the localization occures. For this reason,the statistics can indicat the failure of rock. It is expected that this methord can be used to predict and forecast disasters when field observation system is designed.