Ground displacement is an inevitable problem in the excavation of tunnels and underground spaces near the surface. The importance of surface settlement increases with a reduction of the depth of tunnelling. In urban areas, when settlements exceed the allowed value, they can damage surface and subsurface structures. Therefore, the identification of factors that affect settlements is critical. One of the essential factors is the grouting behind the segmental lining of a tunnel. An annular gap behind the segmental ring usually causes more problems such as surface settlement and displacement and damage to the precast concrete and unsuitable sealing. Void thickness has a large effect on the amount of maximum surface settlement and the shape of the surface settlement curve. This study focuses mainly on the effects of the aforementioned parameter on surface settlements. Both numerical and empirical methods were used in this study. In addition, the field data were presented in order to support the predicted surface settlements by 3D numerical modelling. The results obtained from the 3D numerical modelling were in agreement with the field measurements. The obtained results revealed that the amount of maximum surface settlement and shape of the surface settlement curve is strongly related to the annual gap thickness and the grouting operation.

在开挖地面附近的隧道和地下空间时，地面位移是不可避免的问题。随着隧道深度的减小，地表沉降的重要性增加。在城市地区，当沉降超过允许值时，它们可能会破坏地表和地下结构。因此，确定影响住区的因素至关重要。关键因素之一是隧道分段衬砌背后的灌浆。分段环后面的环形间隙通常会引起更多问题，例如表面沉降和移位以及对预制混凝土的损坏和不适当的密封。空隙厚度对最大表面沉降量和表面沉降曲线的形状影响很大。这项研究主要集中于上述参数对地表沉降的影响。在这项研究中使用了数值和经验方法。此外，还提供了现场数据，以通过3D数值建模支持预测的地面沉降。从3D数值建模获得的结果与现场测量结果一致。所得结果表明，最大表面沉降量和表面沉降曲线的形状与年间隙厚度和注浆操作密切相关。从3D数值建模获得的结果与现场测量结果一致。所得结果表明，最大表面沉降量和表面沉降曲线的形状与年间隙厚度和注浆操作密切相关。从3D数值建模获得的结果与现场测量结果一致。所得结果表明，最大表面沉降量和表面沉降曲线的形状与年间隙厚度和注浆操作密切相关。