为了解软土地区盾构法综合管廊工作井小尺寸深基坑施工过程的空间效应，以宁波市通途路综合管廊工程沿线9座工作井深基坑为研究背景，介绍工作井深基坑支护结构的设计情况，借助三维有限元分析软件建立1#工作井深基坑数值分析模型，引入比例系数R对基坑开挖过程中地连墙及周边不同距离外土体的变形特性进行深入分析，并以2#深基坑作为验证。结果表明： 1）在深厚软土层中进行小尺寸深基坑开挖时，不同深度处基坑空间效应的影响范围基本一致，但深层土体受空间效应的影响大于浅（表）层土体； 2）空间效应的临界尺寸值可结合数值计算获取，影响范围内R值呈非线性增大，影响范围外R值稳定为1.0，符合平面应变假定； 3）当基坑长度方向尺寸小于临界值时，采用现有规范法计算偏于保守，建议结合三维整体分析模型对支护结构进行合理优化。

To clarify the spatial effect of the smallscale deep foundation pit of utility tunnels using shield method during construction process, a case study is conducted on nine working shaft foundation pits along the Tongtu road utility tunnel project in the central area of Ningbo, China, and the design of supporting structure for deep foundation pit of working shaft is introduced. Then the threedimensional numerical calculation model of #1 working shaft foundation pit is established using finite element analysis method, and the deformation characteristics of the diaphragm wall structure and the surrounding soil during the excavation of foundation pit are analyzed by introducing the scale coefficient 〖WT５《TNR#I》〗R〖WT５《TNR》〗. The results reveal the following: (1) In the deep soft soil layer, the influencing ranges of spatial effect at different depths are almost the same, whereas the influence of spatial effect on deep soil is relatively larger than shallow soil. (2) The critical dimention value of the spatial effect can be obtained based on numerical calculation. Within the influence range of spatial effect, the increase of 〖WT５《TNR#I》〗R〖WT５《TNR》〗 value is nonlinear, otherwise, the 〖WT５《TNR#I》〗R〖WT５《TNR》〗 value is stable at 1.0, which agrees plane strain assumption. (3) The calculation method of standard method is conservative if the dimension of the long side of the foundation pit is less than the critical value. The influence range of spatial effect can be judged in combination with threedimensional numerical calculation, and the support structure design can be optimized.