Experimental Study on the Stick-slip Phenomenon of Intact Granite under Solid Confining Pressure

In this paper,compression tests of intact granite samples have been made in a triaxial testing machine with solid confining pressure.From the tests,the influences of confining pressure and loading rate(axial strain rate)on the deformation and fracture process of rock samples,on the stress drop and recurrence interval of stick-slip events,and on the geometric distribution of the main fracture have been studied.The experimental results show that the loading rate influences the stress drop and recurrence interval of stick-slip events greatly.At lower loading rates,the stress drop of stick-slip events is greater,their recurrence interval is longer and shows no regularity in distribution.When the loading rate goes higher,the stress drop will become smaller and the recurrence interval will tend to be constant and stick-slip events show a quasi-periodicity.At lower confining pressures and strain rates,the main fracture may evolve into 2 X-shaped conjugate shear faults; whereas at higher confining pressures

In this paper,compression tests of intact granite samples have been made in a triaxial testing machine with solid confining pressure.From the tests,the influences of confining pressure and loading rate(axial strain rate)on the deformation and fracture process of rock samples,on the stress drop and recurrence interval of stick-slip events,and on the geometric distribution of the main fracture have been studied.The experimental results show that the loading rate influences the stress drop and recurrence interval of stick-slip events greatly.At lower loading rates,the stress drop of stick-slip events is greater,their recurrence interval is longer and shows no regularity in distribution.When the loading rate goes higher,the stress drop will become smaller and the recurrence interval will tend to be constant and stick-slip events show a quasi-periodicity.At lower confining pressures and strain rates,the main fracture may evolve into 2 X-shaped conjugate shear faults; whereas at higher confining pressures and strain rates,the main fracture of rock appears as a single shear fault or X-shaped shear fault.The results of this paper are of important significance.They can help us to understand the generation,occurrence and recurrence processes of earthquakes and to study the recurrence mechanism of earthquakes as well as the main factors that influence the recurrence interval.