中文摘要：

为了合理地描述岩石的阻尼行为,提出了考虑轴向和环向阻尼振动的岩石阻尼参数计算方法;通过动循环荷载、分级循环荷载和常幅循环荷载试验,对比分析了这3种不同应力路径下砂岩、砾岩及砂砾岩的阻尼特性,得到了阻尼参数对应力幅值、应变幅值的响应特性,揭示了常幅循环加载过程中阻尼比和阻尼系数随循环次数的演化规律;从熵守恒和能量守恒定律出发,建立了岩石阻尼比随循环次数演化的经验模型。结果表明：（1）动荷载下岩石的阻尼比与轴向应变幅值成线性递增,而阻尼系数恰好相反;分级循环荷载下岩石的阻尼参数都随应力幅值成线性递增。（2）疲劳破坏门槛值是岩石耗散能和阻尼比演化规律发生变化的分界点,在应力上限高于疲劳破坏门槛值时,耗散能、阻尼比及阻尼系数随循环次数都呈3阶段的变化规律,演化曲线呈半U型;在应力上限低于疲劳破坏门槛值时,呈现2阶段的发展规律,演化曲线呈L型;（3）通过砂岩的阻尼比试验,验证了所建模型能够描述砂岩在常幅循环荷载过程中阻尼行为。

英文摘要：

To better describe the damping behavior of rock,a new method was developed to calculate damping parameters in consideration of lateral and longitudinal damped vibrations.A series of damping experiments was also conducted on sandstone,conglomerate and glutenite under dynamic cyclic loading,the stepped cyclic loading and the constant amplitude cyclic loading,respectively.Then response characteristics of damping parameter to stress amplitude and strain amplitude were both obtained.This study revealed the evolution laws of the damping ratio and the damping coefficient with the cycle number under the constant amplitude cyclic loading.In addition,an empirical model was derived for the evolution of the damping ratio with the cycle number,based on the laws of entropy conservation and energy conservation.From experimental results,the damping ratio of rock increased with increasing the axial strain amplitude under dynamic cyclic loading,whereas the damping coefficient decreased.Under stepped cyclic loading,the damping ratio and damping coefficient of rock increased with the increase of axial stress amplitude.It is found that the threshold for the fatigue failure of sandstone was the point where the evolution law of dissipation energy and damping changed suddenly.If the upper limit of stress was higher than the threshold for fatigue failure,all evolution curves of the dissipated energy,the damping ratio and the damping coefficient were half U–shape and characterized by three phases.On the contrary,their evolution curves were characterized by L-shape and two phases.Through the damping ratio experiments of sandstone,it is verified that the model was capable of describing the energy dissipation and the damping behavior in constant amplitude cyclic loading process.