水质分析在重庆笔架山隧道防腐设计中的应用

The application of water quality analysis in corrosion prevention design of Bijiashan tunnel, Chongqing City

我国是拥有隧道数量最多及总长度最长的国家。同时也是隧道病害最严重的国家之一。由于隧道的主体是处于天然介质环境中的人工地下结构,在运营中会出现衬砌腐蚀等多种病害和危害。进行合理的防腐设计对隧道的安全、舒适、正常运营具重大意义。在南方富含腐蚀性介质地区,地下水容易沿衬砌的各种孔洞渗流到衬砌内侧,成为隧道渗漏水,对衬砌混凝土等产生侵蚀作用,造成衬砌腐蚀。故地下水对混凝土的侵蚀性是隧道防腐设计的重要组成部分。作者在掌握笔架山隧道工程地质、水文地质资料及查明环境水含腐蚀性介质的来源、成分基础上,利用隧道水简(化学)分析、地质调查、裂隙水统计等手段定性及定量评价环境地下水对衬砌混凝土腐蚀程度。认为基岩地下水不会对衬砌产生化学腐蚀。从而科学地修正了隧道的防腐设计。此结论及时反馈于施工,在后来的施工中取消了耐腐蚀混凝土及其它混凝土外加剂,节省了投资,加快了施工进度。

China is a country which have the most and longest tunnels, but at the same time China is also one of the countries which have much more serious tunnel disasters. Because the tunnel is a manual underground structure, which constructed in natural environment, a right corrosion prevention design is necessary for the tunnel's working smoothly, safety and comfort. In karst topography areas of south China, groundwater will seep into the liner through the capillary holes around the tunnel and to be water seepage, which will be corrosive to the lining, so the underground water corrosion to tunnel lining is a critical problem in corrosion prevention design of the tunnel. The authors collected the data of the engineering geology and hydrogeology of Bijiashan Tunnel and found the source and ingredient of corrosive medium in underground water. By using qualitative and quantitative evaluation methods such as water quality analysis, geological survey, fissure water statistics, etc., the authors think that bedrock water has no chemical corrosion to the lining. The results revise the initial corrosion prevention design and feed bac to the construction. The corrosion resistant concrete and other additives can be canceled, so the cost of the tunnel will be saved and the construction schedule will be shortened.