【摘要】 利用MTS 815Flex Test GT岩石力学试验系统,对花岗岩进行了不同加载频率单轴压缩下的5级正弦波加卸载试验。正弦波加载频率依次为1、2、3、4Hz,循环应力幅值由岩石平均抗压强度的20%～60%等间距确定,每级应力幅值为400个振动循环。试验结果表明,花岗岩塑性变形随加载次数的增加而逐渐增大,且动应力动应变滞回环为月牙形;同一加载频率下,花岗岩的动弹性模量、动泊松比和单位体积耗散能随动应力水平的升高而升高,且随着加载频率的升高,动弹性模量逐渐降低,而动泊松比和单位体积耗散能逐渐升高,表明动荷载频率越高,对岩石劣化作用的能力越强;同一级动荷载下花岗岩动弹性模量和动泊松比随循环周次增加而变化不明显,单位体积耗散能随循环周次增加逐渐减小。更多还原

【Abstract】 The uniaxial five stress levels cyclic loading and unloading tests under different loading frequencies for granite are carried out on the MTS 815 Flex Test GT rock mechanics test system in sine wave.Sine wave loading frequencies were 1Hz,followed by 2Hz,3 Hz and 4 Hz,cyclic stress amplitude depended on 20% to 60% average of rock compressive strength on same space,and the cyclic number of every level cyclic stress was 400 cycles.The research results are shown as follows: with the increase of loading times,the plastic deformation of granite increases gradually;the hysteresis loop of dynamic stress and strain is the crescent;meanwhile,under the same loading frequency,granite’s dynamic elastic modulus,dynamic Poisson’s ratio and the energy dissipation of unit volume increase progressively with the increment of dynamic stress amplitude;along with loading frequency increasing,the dynamic elastic modulus gradually reduce,and dynamic Poisson’s ratio gradually rises as well as the energy dissipation of unit volume;the results suggest that the higher frequency of the dynamic loading,the stronger ability the dynamic loading has to weaken rock;under the same level of dynamic loading,granite’s dynamic elastic modulus and dynamic Poisson’s ratio change little with the increment of loading times,but the energy dissipation of unit volume gradually decreases.更多还原