节理岩体的一维动态等效连续介质模型的研究

AN EQUIVALENT 1D DYNAMIC CONTINUUM MODEL FOR ROCK MASS WITH PARALLEL JOINTS

基于黏弹性理论,提出平行节理岩体的一维动态等效连续介质模型,该模型适用于纵波(P波)垂直通过一组等间距平行节理岩体的动力学问题。该模型包含黏弹性介质模型和虚拟波源概念。黏弹性介质模型主要描述应力波通过节理的衰减和时间的滞后;而虚拟波源的概念则描述应力波在平行节理之间的多次反射。根据已有解析解可以确定黏弹性介质模型中的未知参数。通过和位移不连续方法的比较,验证平行节理岩体的一维动态等效连续介质模型的正确性;该模型可有效地应用于研究通过一组平行节理岩体的P波传播问题。结果表明,该研究可以简化应力波传播问题的复杂性。

Based on viscoelastic theory,an equivalent one-dimensional dynamic continuum model is proposed for rock mass with parallel joints. The model includes two portions,one is the viscoelastic medium model and the other is the concept of＂virtual wave source（VWS）＂. The time retardation and attenuation of longitudinal wave propagation across jointed rock mass are considered in the viscoelastic medium model;and the concept of VWS is adopted to account for the wave reflections between joints. The parameters in the equivalent viscoelastic model are derived analytically based on existing solution for longitudinal wave propagation across a single rock joint. The proposed model is then verified by applying identical incident waves to the discontinuous and equivalent dynamic media at one end and receiving output waves at the other end,i.e. by comparing two results from the displacement discontinuity method and the present equivalent medium method. The results show that the proposed model can simplify the simulation of stress propagation effectively.