湿度扩散诱发的节理岩体时效变形特性研究

湿度对岩体结构性能的影响显著,不仅造成岩体物理力学性能弱化,还在一定程度上产生湿涨变形,进而改变岩体的应力状态,大大增强岩体的时效变形特性。为了分析节理岩体在高湿度环境下的时效变形,采用湿度-应力-损伤耦合数值模型对水敏感岩体隧洞开挖后的变形量、围岩内的湿度扩散,以及应力演化进行了数值分析。通过对单组和2组节理岩体的变形、应力、湿度扩散的分析,揭示了节理弱面对湿度扩散和岩体变形的强化作用。开挖隧洞拱顶和底板变形量的分析结果表明高湿度环境是水敏感岩体隧洞产生底鼓的重要原因之一。湿度扩散引起隧洞顶部和底部围岩产生大量破坏,致使相应部位的位移量陡增。此外,单组节理对岩体的湿度扩散的方向起到明显的导向作用,而多组相互斜交的节理则在一定程度上削弱了湿度扩散的各向异性。

Study on humidity diffusion induced time-dependent deformation of jointed rock mass

Humidity may significantly influence the performance of rock mass.It not only weakens the physical and mechanical properties of rock mass,but also results in swelling deformation,which greatly enhances the time-dependent deformation of rock mass.In order to analyze the time-dependent deformation of joined rock mass under highly humid condition,a newly developed humidity-stress-damage coupling model is used to study the deformation of excavated tunnel,as well as the long term humidity diffusion and stress evolution processes in surrounding rock.By studying the deformation process,stress evolution and humidity diffusion of single and two groups of jointed rock mass,it further reveals the strengthening effect of joints on humidity diffusion and deformation of surrounding rock.The deformation at roof and floor indicates that high-humidity environment is one of the major reasons of floor heave.Humidity diffusion causes plenty of failures at the top and bottom of the tunnel,which results in greatly increasing of displacement on corresponding parts.In addition,the single group of joint plays a significant role on changing the direction of humidity diffusion,while multiple joints weaken this type of anisotropy.