中文摘要：

考虑基坑坑底与侧壁卸荷应力以及基坑围护结构的影响，建立基坑开挖力学计算模型。基于Mindlin应力解公式，推导得到基坑开挖引起的临近既有地铁隧道的附加荷载计算公式，并对基坑尺寸改变、隧道位置改变以及加固控制措施这3方面的影响因素进行分析。算例分析结果表明：（1）当隧道位于基坑旁边时，基坑侧壁卸荷作用对隧道的影响非常大，坑底卸荷作用则影响较小，但当基坑开挖深度较浅时则影响会增大；（2）在水平向隧道受到朝向基坑一侧的拉力，数值较大。在竖向隧道受到竖直向上的拉力或向下的压力，数值小；（3）S，B，d及β这4个影响因素改变对隧道的水平向受力影响最大，三改变的影响次之，h改变的影响最小；（4）d改变对隧道的竖向受力影响最明显，其次为S，B改变的影响，其余影响因素改变均不明显。

英文摘要：

To consider the influence of the soil unloading stress of the bottom and the surrounding walls by the foundation pit excavation and retaining structure, the mechanics model of foundation pit excavation was established. Based on Mindlin formula, the calculation formula of metro tunnels additional load caused by adjacent foundation pit excavation was derived. And the influence factors were analyzed, such as the foundation pit excavation size and tunnel position and the reinforcement control measures. The calculation results show that： （1） Soil unloading stress of the surrounding walls has a large effect on tunnel when the foundation pit beside tunnels, conversely the influence of soil unloading stress of the bottom is small. However, the influence of soil unloading stress of the bottom will increase when the depth of excavation is shallow. （2） In the horizontal direction to the foundation pit, the pull power on the tunnel is large. But In the vertical direction, the pressure power up or down on the tunnel is small. （3） The change of s, B, d and fl will play a largest important role in the stress of tunnels in the horizontal direction. The influence of the change of L is second. And the influence of h is the smallest. （4） The change of d will play the most obviously important role in the stress of tunnels in the vertical direction, then is the change of s, B. The influences of other factors are not obvious.