为研究溶洞诱发上覆砂层塌陷对既有盾构隧道的影响规律，提出一种基于地层参数折减的等效模拟方法，并给出地层参数折减范围与折减系数的确定方法，结合武汉地铁11号线，分析了不同赋存条件及规模的溶洞诱发上覆砂层塌陷对地表沉降以及既有隧道变形的影响规律。研究结果表明： 1）溶洞上覆砂层塌陷会导致既有盾构隧道所在地层变形增大，溶洞位于隧道正下方时的地表沉降曲线呈“V”型，而溶洞位于隧道侧下方时，所在地层的地表沉降最大值向溶洞赋存位置处偏移。2）溶洞上覆砂层塌陷引起隧道衬砌结构压应力在隧道拱顶和拱底位置增大较为显著，最大增量出现在隧道底部；随着溶洞规模的增大，隧道衬砌结构压应力在拱底处呈逐渐增大趋势，但增加幅度逐渐减小；溶洞位于隧道正下方时，其上覆砂层塌陷对隧道结构应力的影响更为显著。

To study the influence of the overlying sand layer collapse induced by the karst cave on the existing shield tunnel, an equivalent simulation method based on stratum parameter reduction is proposed, and the methods of the stratum parameter reduction range and coefficient are also determined. The surface settlements and deformations of existing tunnels when the collapses of the overlying sand layer induced by karst caves with different occurrence conditions and scales are analyzed based on Wuhan metro line 11. The research results indicate the following: (1) The collapse of the sand layer over the karst cave will increase the stratum deformation of the existing shield tunnel. When the karst cave is located directly below the tunnel, the surface settlement curve presents a V shape, whereas when the karst cave is located below one side of the tunnel, the maximum ground settlement deviates from the location where the karst cave occurs. (2) The collapse of the overlying sand layer on the karst cave causes a significant increase in the compressive stress of the tunnel lining structure at the top and bottom of the tunnel, and the largest increment occurs at the bottom of the tunnel. With an increase in the scale of the cave, compressive stress of tunnel lining structure increases gradually at the bottom of arch, but the increase gradually decreases; when the karst cave is located directly below the tunnel, the impact of the overlying sand layer collapse on the tunnel structure stress is more significant.