某铁路隧道隧址区水文地质条件分析与洞身涌水量预算

通过详细分析隧道址区水文地质资料,认为石炭系灰岩、三叠系中统河湾组白云质灰岩和上统大水塘组下段安山玄武岩为强含水层组,大量的岩溶发育于石炭系灰岩和三叠系中统河湾组白云质灰岩中。以井水断层及太元背斜为界,将研究区分为太元背斜和街子坡复式向斜2个水文地质单元,并对各单元中水量、水质与地下水的补给、径流及排泄条件等进行了说明。采取并测试了13组地下水同位素样品,结果发现,区内地下水均来源于大气降水。应用地下水动力学和降水系数法对隧道洞身的涌水量进行了预测,推断隧道的正常涌水量为56 880m3/d,最大涌水量为68 300m3/d。为防止隧道塌方,提出了"短进尺、快循环、弱爆破、少扰动、紧封闭、超前注浆"的施工方法,并要求在施工中做好超前地质预测工作。

Hydrogeological Conditions of a Railway Tunnel Site and Tunnel Trunk Water Inflow Prediction

Through detailed analysis of hydrogeological information from tunnel site, considered that the Carboniferous limestone, Middle Triassic Hewan Formation dolomitic limestone and Lower Member of Upper Triassic Dashuitang Formation andesitic basalt are strong aquifer groups, numerous karst developed in Carboniferous limestone and Middle Triassic Hewan Formation dolomitie limestone. To take the Jingshui fault and Taiyuan anticline as boundary, divided the study area into Taiyuan anticline and Jiezipo compound syncline two hydrogeological units, and illustrated water yield, water quality and groundwater recharge, runoff and discharge conditions of each unit. 13 sets of groundwater isotopic samples were collected and tested, the results demonstrated that all groundwater in the area is come from atmospheric precipitation. To use groundwater dynamics and rainfall infiltration coefficient methods carried out tunnel trunk water inflow prediction, the inferred normal inflow is 56889m3/d, maximum 68300d3/d. To prevent tunnel from cave in, a construction method with ＂shorter footage, faster circulation, weaker blasting, less disturbing, closer sealing, advanced grouting＂ put forward, and advanced geological prediction is required during construction.