盾构隧道施工沥青路面容许沉降值分析

Analysis of Allowable Settlement Value of Asphalt Pavement in Shield Tunneling

通过理论公式和有限元计算,分析了沥青路面在盾构隧道施工引起的地面不均匀沉降下的力学响应规律后,认为:沥青路面结构基层层底拉应力最大,在沉降量较大时可能会发生弯拉破坏,可视为应力控制层。在分析现有规范要求、基于变坡指标要求的地面容许沉降值的基础上,提出了在隧道埋深不大时,基于路面结构自身受力安全角度计算所得路面沉降值具有控制意义;并针对某一特定地层条件(k=0.5)计算分析后,建议盾构隧道覆土厚度为8 m和12 m时容许沉降值分别取18 mm和34 mm。

The mechanical response law of asphalt pavement under uneven ground settlement caused by shield tunneling construction is analyzed by theoretical formula and finite element calculation.The results show that the tensile stress at the bottom layer of asphalt pavement structure is the largest.When the settlement is large,its’flexural tensile failure is likely to occur which can be regarded as stress control layer.On base of analyzing the existing code and allowable ground settlement required by variable slope index,it is suggested that the pavement settlement value,which is calculated based on the stress safety angle of the pavement structure itself,has control significance when the tunnel is not buried deep.According to the calculation and analysis of a specific ground condition(k=0.5),the allowable settlement value of 8 m and 12 m soil thickness are recommended to be 18 mm and 34 mm respectively.