盾构压力隧洞双层衬砌的力学模型研究

本文以我国规划设计中的南水北调中线穿黄隧洞为工程背景，对双层衬砌的结构计算方法进行研究。文中根据管片施工后外部水土压力达到稳定时间长短的不同，提出了衬砌受力的两种叠加模型；根据内外衬砌接合面结构形式的不同，建立了三种双层衬砌相互作用模型；根据上述模型编制了有限元计算程序，对穿黄隧洞双层衬砌的结构内力进行了计算，并对不同模型计算结果的差别进行了对比。计算结果表明：对于盾构开挖的双层衬砌水工压力隧洞，通常使用的由外管片单独承担全部外水土压力的假定是一种偏于危险的设计方法，设计中应增强内外衬砌接合面的结构联结，以便形成有效的受力整体。

Mechanical model for shield pressure tunnel with secondary linings

Two kinds of load combination model are proposed for different situations of external water and soil pressure. In the mean time three joint interaction models corresponding to different forms of joint between primary and secondary linings are suggested. Programs for FEM to calculate the stress of the linings are coded. The calculation results show that the assumption of secondary lining solely bearing the total water and soil pressure is not correct and may induce unsafe errors in lining design. It is recommended that the commended that the coupling bwtween primary and secondary linings must be reinforced forming an integrated structure to bear the external pressure.