Abstract This study investigates the characteristics of vertical soil deformation induced by fully overlapping tunnels constructed using a tunnel boring machine (TBM). The Peck formula is improved to consider the variation in the tunnel axis depth and stratum loss ratio. Comparing the settlements both monitored and simulated on the fully overlapping tunnels of the Tianjin Metro, it is shown that our improved Peck formula is suitable to predict the surface settlement of fully overlapping tunnels. The present comprehensive research shows that during the construction of fully overlapping tunnels, the ultimate maximum settlement value is more affected by the construction of an upper-line tunnel than by the construction of a lower-line tunnel. The width of the ground settlement trough in fully overlapping tunnels construction is only affected by the lower-line tunnel, but the final settlement value is not simply the sum of the settlements of the two tunnels. The overlapping effect between the upper and lower lines reduces the stratum loss and the maximum settlement caused by excavation of the upper-line tunnel.

中文翻译：

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粘土地层隧道掘进机全搭接隧道地表沉降特性

摘要 本研究调查了使用隧道掘进机（TBM）建造的完全重叠隧道引起的垂直土壤变形特征。改进了 Peck 公式以考虑隧道轴线深度和地层损失率的变化。对比天津地铁全搭接隧道监测和模拟的沉降，表明改进的Peck公式适用于预测全搭接隧道的地表沉降。目前综合研究表明，在全搭接隧道施工过程中，上线隧道施工对最终最大沉降值的影响大于下线隧道施工。全重叠隧道施工中地面沉降槽的宽度仅受下线隧道影响，但最终沉降值并非简单地为两条隧道沉降量之和。上下线的重叠效应减少了上线隧道开挖造成的地层损失和最大沉降。