膨胀性地层铁路隧道衬砌结构及防排水措施优化建议

结合膨胀性地层铁路隧道病害概况以及单、双线铁路隧道断面、防排水设计现状,提出相应的衬砌结构及防排水措施优化建议。衬砌结构的优化建议如下:对单线隧道而言,适当增大其边墙曲率、仰拱矢跨比,提高边墙、仰拱的强度和刚度;对双线隧道而言,适当增大其仰拱矢跨比,提高仰拱的强度和刚度;隧道仰拱处二次衬砌应采用钢筋混凝土,同时在隧道仰拱填充中增设格栅钢架或在隧道仰拱填充顶部增设钢筋。防排水措施的优化建议如下:将设置在仰拱填充内的中心水沟下移至仰拱下方,在仰拱下方设中心水沟或改设为排水渗沟,可将隧道衬砌背后积水均引入仰拱下方的中心水沟排出洞外;而改设的中心渗沟主要用于排出仰拱下方积水。

Optimization Suggestion on the Lining Structure and Waterproof and Drainage Measures of Railway Tunnel in Swelling Stratum

Based on the defect condition of the railway tunnel in the swelling stratum, the tunnel section and present design conditions of the structure shape, waterproof and drainage measures for single-track and double-track railway tunnels, some suggestions for optimization of lining structures and drainage measures are proposed. Some optimization suggestions on the lining structure are as follows: for the single-track tunnel, the curvature of the sidewall and the rise-span ratio of the tunnel invert should be increased properly and the strength and rigidity of the sidewall and tunnel invert should be improved. Similarly, for the double-track tunnel, the rise-span ratio of the tunnel invert should be properly increased to improve the strength and rigidity of the tunnel invert. Besides, the steel frame in the invert filling or the steel bar in the roof of the invert filling should be increased and reinforced concrete should be applied in the invert of the secondary lining. The optimization suggestion on the waterproof and drainage measures are as follows: the center ditch in the invert filling should be moved to a lower position in order to gather the water behind the tunnel lining into the central ditch, and the drainage trench below the tunnel invert should be constructed to drain the water below the tunnel invert.