连拱隧道中墙顶部回填砼与围岩偏心接触的影响分析

摘要

根据某高速公路连拱隧道衬砌结构形式,建立了有限元模型,针对回填砼与围岩之间完全左偏心和完全右偏心两种极端接触条件,采用数值模拟方法综合分析了偏心接触时隧道围岩和衬砌结构的变形与受力状况.结果表明,回填砼与围岩之间偏心接触虽然对拱顶沉降影响不显著,但会引起拱顶围岩拉应力和内衬弯矩的显著增长,同时造成中墙产生严重偏压.%A finite element model was established based on the lining structure of multi-arch tunnel in expressway. In the light of left and right eccentric situation occurred between backfill concrete and surrounding rock, the deformation and stress of surrounding rock and lining structure under such situation were comprehensively analyzed by numerical simulation method. Results show that such eccentric situation won't bring impact on the settlement of arch roof, but will cause the tensile stress on the arch roof surrounding rock and bending moment of lining greatly increased and remarkable eccentric compression occurred on the mid-wall.