以南通地铁1号线青年路联络线小曲率半径盾构项目为工程背景，针对小曲率半径隧道施工超挖和转弯引起的地层变形问题，利用数值模拟和现场监测相结合的方法，揭示小曲率半径隧道施工对地层变形的影响规律。数值和监测结果表明： 不同于直线盾构隧道推进对地层的影响规律，曲线段盾构隧道掘进过程中曲线外侧地表沉降量小于曲线内侧；并且由于盾构隧道转弯过程中刀盘在内侧超挖，在内侧产生了附加卸荷作用，使隧道上方土体沉降和下方土体的隆起显著增加。隧道转弯施工引起隧道上方土体的水平位移基本对称，位移方向为指向隧道中心方向；对于隧道中心处周围的深层土体而言，隧道转弯施工引起的内外两侧土体水平位移呈非对称状态，方向指向隧道外侧方向。

In this study, a case study is conducted on shield tunnel with small curvature radius on Qingnian road connecting line of Nantong metro line 1, and the tunnelinginduced disturbance on stratum and tunnel structure is monitored and analyzed. A threedimensional numerical model of shield tunneling is established to simulate the tunneling process. The results show the following: (1) The surface settlement outside the curve is less than that inside the curve. (2) The overexcavation of the cutterhead at the inner side produces an additional unloading effect. As the consequence, the vertical displacement of the soil above and below the tunnel increase dramatically. (3) The horizontal displacement of the soil at the upper sides of the tunnel is basically symmetrical, and moves towards the tunnel center. (4) The horizontal displacement of the soil at the tunnel center is asymmetric, and moves towards outside of the tunnel at both sides of the tunnel.