考虑施工顺序的邻近平行隧道地表变形计算方法

邻近平行隧道施工顺序的差异会导致其最终地表变形出现偏移现象,为此,建立了考虑先后施工顺序影响的邻近平行隧道地表变形计算方法。首先,基于平行隧道施工叠加扰动机理,对平行隧道进行分类;其次,根据地层扰动特征和变形叠加原理,确立平行隧道地表变形计算流程;然后,通过对后施工隧道开挖引起的地面沉降实测数据进行分析,建立后施工隧道地面沉降曲线修正系数拟合公式;最后,对计算方法进行算例验证。研究结果表明:后施工隧道的地面沉降曲线修正系数k与两隧道轴线的相对水平距离系数z呈线性递减关系;后施工隧道地表变形曲线修正系数拟合公式适用性较好;采用考虑施工顺序影响的平行隧道地表变形计算方法获得的地表变形曲线与实测结果吻合。研究成果是对传统Peck公式的有效补充,对分析邻近平行隧道施工引起的地表变形特征具有参考价值。

Construction sequence-considered method for calculation of surface deformation of adjacent parallel tunnels

Aiming at the phenomenon of the deviation of the final ground surface deformation caused by the difference between the construction sequences of the adjacent parallel tunnels，a method considering the influence from the construction sequence for calculating the surface deformation of adjacent parallel tunnels is established． Firstly，the parallel tunnels are classified based on the mechanism of superimposed disturbance of parallel tunnel construction; and then the calculation process of surface deformation of parallel tunnel is established according to the characteristics of stratum disturbance and the principle of deformation superimposition; afterwards，the fitting formula of the correction coefficient for the post-construction tunnel surface settlement curve is built up; finally，the calculation method is verified through a relevant calculation case． The study result shows that the correction coefficient k of the tunnel post-construction surface settlement curve exhibits a linear degressive relationship with the relative horizontal distance coefficient z between both the two tunnel axes，while the applicability of the fitting formula of the post-construction tunnel surface deformation curve correction coefficient is better and the surface deformation curve obtained with the method for the calculation of parallel tunnel surface deformation is coincided with that from the measured result． The study result is an effective supplement to the conventional Peck formula，thus has a certain referential value for analyzing the characteristics of the surface deformation caused by the constructions of adjacent parallel tunnels．