【摘要】 目的研究由爆破引起的冲击波对隧洞群围岩应力和塑性区的影响.方法采用大型有限元FLAC3D软件,对取水隧洞钻爆开挖过程进行建模分析和数值模拟.结果开挖过程中围岩剪切应力发展很快,开挖隧洞下台阶后比开挖上台阶时塑性区分布区域进一步加大,以剪切塑性区为主;在爆破动荷载作用下,应力波对围岩的破坏作用是从降低其抗剪强度开始的;在钻爆开挖过程中,隧洞两侧及附近范围内塑性区以拉应力为主,当动载达到一定程度时岩体可能失稳破坏.结论在隧洞群施工过程中,隧洞围岩在爆破引起的冲击波作用下可能失稳破坏,应采取有效支护措施,预防隧洞两壁及其附近围岩的失稳、塌陷.更多还原

【Abstract】 In order to study the developing range of wall rock stress around tunnel and plastic zone caused by blasting shockwave,the research applied finite element software FLAC3D to carry out simulation analysis.The results show that shear stress has developed rapidly in the process of wall rock excavation;the plastic zone distribution has enlarged further when the lower part of step is excavated than it is when the higher part of step is excavated.Shear stress plastic zone is the main part.Under the action of active loads,stress wave damaging effects on the wall rock begins with shear strength reduction.In drill and blast excavation process,plastic zones of the tunnels on both sides and nearby are consist in tensile stress;the rock mass may be unstable and damaged when the active load reaches a certain level.The conclusion shows that effective support measures should be adopted to prevent instability and collapse of the wall rock around tunnels.更多还原