应力波反复作用下断续节理岩体疲劳破坏试验研究

试验研究了反复应力波作用下断续节理岩体的疲劳破坏过程和特征,讨论了节理充填性质、节理倾角、侧向静压等因素对岩体动态疲劳破坏的影响。结果表明:疲劳损伤累积过程受节理倾角与应力波传播方向影响,两者夹角越大损伤破坏越不均匀,但强度降低率小;充填介质能在一定程度上削弱应力波的损伤作用,减缓损伤累积进程;损伤累积过程在一定程度上受控于侧压,随着侧压增大损伤累积速率和强度降低速率减缓。

EXPERIMENTAL STUDY ON FATIGUE FAILURE OF INTERMITTENT JOINTED ROCK MASSES SUBJECTED TO REPEATED STRESS WAVE

The fatigue failure behaviors of intermittent jointed rock masses subjected to repeated stress waves are investigated on the basis of experiments. In order that failure modes in the experiments can be easily observed,all specimens are made of transparent organic glass plate. A tailor-made exploder is used to offer dynamic loads. For static loading,axial stress is provided by a testing machine,and lateral stress is given by a set of jack. Affecting factors which may influence the dynamic fatigue failure property of rock mass,such as joints angles,stuffing characteristics and lateral pressures,are analyzed. Experimental results indicate that damage accumulation of intermittence rock mass is markedly related to the intersection angle between joints and propagation direction of stress waves,and damage distribution will be more nonuniform with the increase of that angle. When the intersection angles are small,the initiation of wing cracks near the tip of joints and damage accumulation are even correspondingly. But for larger intersection angles,fracture and damage are localized on the side of incident waves. For different stuffing cases,results show that joints stuffed with fillings are more favorable for the propagation of stress waves than that of unfilled;but stuffing may decrease the rate of damage accumulation and increase the fatigue life of rock mass. Also,the rate of damage accumulation is controlled by lateral pressure,which decreases along with the increase of lateral pressure. These experimental results show that the fatigue failure of intermittent jointed rock masses are quite complex.