高压富水区限排隧道围岩与衬砌水压力场研究

以穿越重庆市中梁山高水压岩溶区的石板隧道为例,采用有限元稳态渗流分析方法,对地下水控制排放下隧道衬砌周围与围岩内的水压力场进行了研究,分析了半包防水与全包防水条件下衬砌上的水压力分布规律,以及全包防水条件下注浆与否围岩内的孔隙水压力特征。研究表明:(1)采用全包防水,不但可以改善隧道的防水条件,而且可以缓解仰拱的水压力,这对于隧道衬砌的耐久性是有利的;(2)隧道排水率对隧道衬砌周围的水压力有显著影响,当地下水较丰富时,注浆可使隧道排水率增加、衬砌压力减小;(3)围岩注浆可以减小隧道排水对围岩水压力的影响范围,且孔隙水压力在注浆圈范围内变化梯度很大。

Water Pressure Field Study of Surrounding Rock and Lining of Controlling Emission Tunnel in High-pressure and Water-rich Zone

Based on the case of Shiban tunnel locating in a region with high water pressure and karst ot Zhong Liang Mountain in Chongqing,hydraulic field of tunnel lining and surrounding rock with controlling groundwater emission was studied using the steady seepage method of finite element.The water pressure distribution laws on lining with half wrapped waterproof and fully wrapped waterproof conditions were studied.Meanwhile,pore water pressure characteristics of surrounding rock were analyzed when grouting or not were analyzed for the case of fully wrapped waterproof.The results show that,(1) the fully wrapped waterproof not only improves the condition of the tunnel waterproofing,but also can release the water pressure of inverted arch,which is more beneficial for the durability of tunnel lining.(2) Drainage rate of tunnel has a significant effect on the water pressure of tunnel lining.When the groundwater is rich,grouting can increase the drainage rate of tunnel and decrease lining pressure.(3) Surrounding rock mass grouting can reduce the influence area of tunnel drainage on the water pressure of surrounding rock.The pore water pressure in the range of grouting circle has a great changing gradient.