为研究旁侧开挖对邻近盾构隧道横向变形的响应规律，提出一种考虑基坑围护结构变形、隧道初始状态、尺寸效应及纵向作用影响的盾构隧道横向变形理论分析方法，探讨隧道截面尺寸、埋深以及与围护结构的水平净距等因素对隧道横向变形的影响规律。基于杭州市之江运河隧道旁侧的某深基坑工程，采用实测和数值分析等手段验证理论解，揭示坑外土体附加应力分布规律与隧道横向变形的响应机制。研究结果表明： 1) 旁侧开挖引起的隧道横向变形随隧道截面尺寸的增加近似呈抛物线形增加； 2) 当隧道中轴线埋深大于2.5倍基坑开挖深度时，水平净距对邻近隧道的横向变形影响较小； 3) 当基坑与隧道水平净距大于40 m时，隧道埋深对邻近隧道的横向变形影响较小； 4) 计算结果基本可以真实反映旁侧开挖引起的隧道横向变形和椭圆度的变化规律。该方法为预测基坑开挖引起的隧道结构变形、内力和病害发展及动态调控基坑施工和保护既有隧道的运营安全提供一种新思路。

A theoretical analysis method for shield tunnel lateral deformation considering factors such as the deformation of the foundation pit enclosure structure, initial state of the tunnel, size effects, and longitudinal actions is proposed. This method aims to explore the response of side excavation to the lateral deformation of existing shield tunnels. The study examines the influence of tunnel section size, burial depth, and horizontal net distance from the enclosure structure on tunnel lateral deformation. Based on a deep foundation pit project near the Zhijiang Canal tunnel, the theoretical solution is validated through field measurements and numerical analysis. The results reveal the distribution pattern of additional stress in the soil outside the foundation pit and the response law of tunnel lateral deformation. The results reveal the following: (1) The lateral deformation of the tunnel caused by side excavation increases approximately in a parabolic shape with increasing tunnel section size. (2) When the burial depth of the tunnel′s central axis exceeds 2.5 times the excavation depth of the foundation pit, the horizontal clearance slightly affects the lateral deformation of the adjacent tunnel. (3) When the horizontal clearance between two tunnels exceeds 40 m, the burial depth of the tunnel has a relatively small impact on the lateral deformation of the adjacent tunnel. (4) The calculation results effectively reflect changes in lateral deformation and ellipticity of the tunnel caused by side excavation. This provides a new approach to predicting deformation, internal forces, and defect development in tunnel structures owing to excavation, allowing for the dynamic regulation of foundation pit construction and ensuring the operational safety of existing tunnels.