基于能量法测量节理岩体品质因子的实验研究

品质因子是衡量岩体中应力波衰减特性的一个重要参数。利用分离式霍普金森压杆实验系统对含人工节理花岗岩试样进行单轴冲击压缩实验,研究节理吻合系数(JMC)对岩体试样品质因子的影响。首先,根据品质因子基本概念得出了利用应力波能量计算品质因子的方法,并证明在试样严格满足应力均匀条件时,其与应力–应变曲线方法是等价的。然后,用三波法得到了节理试样的应力–应变曲线,同时用应力波能量方法计算了品质因子。实验结果表明:随着节理吻合系数(JMC)降低,应力–应变曲线滞回环面积增加,节理岩体试样的动态割线模量和品质因子均减小,说明节理接触面积减小弱化了整个试样并且使试样能量耗散能力增加。

Measurement of seismic quality factor of jointed rock based on stress wave energy

The seismic quality factor is commonly used to describe the attenuation characteristics of stress wave propagation across rock masses. In order to research the influence of Joint Matching Coefficients(JMCs) on the seismic quality factor Qs of jointed rock mass，a series of uniaxial impact compression experiments were conducted on the granite specimens containing artificial joint by using the apparatus of split Hopkinson pressure bar(SHPB). A method to calculate the seismic quality factor is proposed based on the variation of stress wave energy and conformed to the concept of seismic quality factor. The method is proved to be equivalent to the stress-strain method on the condition that the stresses on the specimen are uniform. The stress-strain curves were calculated through the three-wave method，while the seismic quality factor of the specimen was calculated with the energy method. The experimental results show that both the dynamic secant modulus and quality factor decrease with the decrease of joint matching coefficient，indicating that a joint with smaller contact area weakens the whole specimen，but enhances the ability of energy dissipation.