为探究门式隔离桩对大直径盾构隧道施工期间产生的地表沉降影响及地表变形规律，基于上海市机场联络线2标段，采用理论推导、数值模拟和现场试验进行了研究和分析。首先通过数值模型及解析公式对比分析了无隔离桩情况下的地表沉降。随后对比了单侧、双侧和门式3种隔离桩设置形式对地表沉降的影响，并利用现有解析公式验证了单侧隔离桩模型的合理性。最后通过现场试验得到了盾构隧道在门式隔离桩内施工产生的地表沉降变化规律。相关结论如下：通过比较及理论验证，门式隔离桩对地表沉降的控制效果最好，并通过工程实践取得了良好的应用效果；随着隧道在门式隔离桩内施工的进行，在近高铁桥桩处地表沉降呈不断上升趋势，在远离高铁桥桩处地表沉降呈现轻微隆起现象；大直径盾构隧道在门式隔离桩内施工产生的地表沉降最大值位于隧道中线位置，隔离桩内距离隧道中心越近沉降量越大，且在靠近隔离桩一侧沉降值明显增加；在隔离桩外侧随距离增加地表沉降逐渐减小，但在0.5倍门式隔离桩宽度范围内地表沉降出现平台段。

To investigate the impact of portal isolation piles on surface settlement during the construction of large-diameter shield tunnels, theoretical derivation, numerical simulation, and in-situ testing were utilized, based on Section 2 of the Shanghai Airport Link Line. Firstly, the ground settlement in free fields was analyzed by comparing numerical models with analytical formulas. Additionally, the effects of three types of isolation piles were compared, including single-sided (verified by existing analytical formulas), double-sided, and portal type. Finally, in-site test of ground settlement was conducted, and the following conclusions were drawn. Through comparison and theoretical verification, it was determined that portal isolation piles provide the most effective control over ground settlement, with successful application results achieved in engineering practice. As tunnel construction progresses within portal isolation piles, an increasing trend in ground settlement near the high-speed railway bridge was observed, while a slight uplift in ground settlement farther from the bridge was noted. The maximum ground settlement was found along the tunnel centerline. Within the isolation piles, settlement increases closer to the tunnel center, with a significant rise on the side adjacent to the isolation piles. Outside the isolation piles, settlement gradually decreased with increasing distance. However, a plateau section appeared within a range of half the width of the portal isolation piles.