高强防寒保温泡沫混凝土研制与工程应用

复杂地层寒区隧道填充材料需兼具防寒保温、抗震和优化支护等性能,为解决常规泡沫混凝土在复杂地层寒区隧道应用中存在的不足,通过正交试验得到了自制泡沫混凝土的最佳配合比,研制了一种高强防寒保温泡沫混凝土.通过室内试验,研究了所制泡沫混凝土的保温性能和冻融劣化特征,并采用数值分析方法探讨了西藏嘎隆拉隧道初衬和二衬之间加设泡沫混凝土垫层后的温度场变化规律.结果表明:该泡沫混凝土具有较好的保温性能和抗冻融损伤性能,同时强度、延性较普通泡沫混凝土都有明显改善.数值计算结果显示,当在初衬和二衬之间增设泡沫混凝土垫层时,其相应位置的温度变幅由不设置时的4.5℃变为2℃,最低温度由1℃提高到了3℃,表明加设所研制泡沫混凝土垫层对于阻止围岩受到隧道内冷空气的侵害具有非常显著的效果.

High-strength and heat insulation foam concrete:developing and applying in cold region tunnel

Because of the characters of high compressibility and ductility,foam concrete can be used as filling material of the preset deformations layer in deep soft rock tunnel. While the filling material of cold regions tunnel in complex strata requirements the properties of cold-proof and heat insulation,anti-seismic,and optimization of support. So in order to solve the deficiencies of ordinary foam concrete,a new type of high-performance foam concrete is developed and the optimum mixture ratio of foam concrete are obtained via an orthogonal experiment firstly. Then,the heat insulation performance and deterioration under frost cycles are studied through indoor tests. Lastly numerical analysis is used to analyze the temperature evolution on the Galongla tunnel in Tibet after adding a foam concrete layer between initial lining and secondary lining. The test results show that the high-per-formance foam concrete which has just been developed owns outstanding properties of cold-proof and heat insula-tion,and the strength,ductility and water tightness of foam concrete have been significantly improved. The nu-merical simulation results show that temperature fluctuation is changed from 4. 5℃with foam concrete layer to 2℃without the layer,the lowest temperature is increased from 1℃to 3℃meanwhile,it indicates that the high-performance foam concrete can remarkably prevent the cold air interference in cold regions tunnel.