Study On The Rock Mechanics Characteristic By Cyclic Load And Statics Load Fit Together

This article take the actual rock mass project as a background, through Performing experiment in laboratory, to study the mechanics characteristic and the destruction properties of rock mass, which under the combined action of cyclic load and the static load.Based on the indoor experiment of the sandstone and the sample of cracked cement with sand under combined Load, first of all, we have researched the mechanics characteristic of sandstone influenced by static load velocity, cyclic load swing and frequency . The text results show that: The strain rate of sandstone is mainly decided by static loading velocity. There is a threshold value of the change law of elasticity modulus and combination load intensity, which is following the static loading velocity. when static loading velocity less than the threshold value, elasticity modulus and combination load intensity do not have obvious change;When it larger than the threshold value , elasticity modulus and combination load intensity increase along with the static loading velocity increases; When cyclic loading amplitude between 0.076σc～0.611σc (σcis the Single axis static load resist pressure strength of sample),the elasticity modulus and combination load intensity of sample descend gradually along with the cyclic loading amplitude increases. Following the increase of cyclic loading frequency, the combination loading of the sandstone descend after increase, and when the frequency is 1HZ,it is maximal. Damaged pattern of sandstone under combined load is mainly decided by cyclic loading amplitude, static loading velocity and cyclic loading frequency have influence on the damaged degree. Second, we have researched the deformation strength characteristics and destruction characteristics under combined Load. The text results show that: The peak intensity and elasticity modulus is smaller ,when the crack angleα= 0°,30°. The peak intensity and elasticity modulus present ascendant trend along with the crack angle increases Contrary to the sandstone, the elasticity and the carrying capacity of the crack sample descends with the velocity. The elasticity and the carrying capacity descends after increase with the swing when cycle load swing between 0.211σc～0.844σc. And exist a doorsill between0.422σc～0.633σc. Analyze to the damage of rock mass, know that damage of rock mass is relevant to static load velocity, cyclic number, cyclic load swing and frequency under combination load.