为解决临河基坑周边施工空间不足、坑外超载、围护结构变形大等问题，提出一种新型组合围护结构——地下连续墙与多排钢板桩组合围护结构。依托宁波轨道交通5号线一期工程兴庄路站地铁车站工程开展现场实测，基于现场实测数据，对比分析组合围护结构的变形特点、作用效果和经济效益，并提出相应的优化建议。结果表明： 1)组合围护结构中地下连续墙两侧变形曲线相同，呈“两头小，中间大”的“内凹型”变形曲线，坑外多排钢板桩呈“踢脚式”的变形曲线； 2)采用组合围护结构的北侧相较于采用常规地下连续墙围护结构的南侧，围护结构水平位移减少7%~24%，围护效果较为显著； 3)临河一侧地下连续墙底部水平位移相对较大，但仍在安全范围内； 4)该组合围护结构围堰面积小，有利于保护临近河道； 5)该组合围护结构有施工便利、施工工期短、可持续经济效益更高等优点。

Foundation pits adjacent to river face many problems such as insufficient construction space, site overloading, and large deformation of the retaining structure. Accordingly, a new type of composite retaining structure, underground diaphragm wall + multirow steel sheet piles, is proposed. Field monitoring test is conducted on Xingzhuang Road station of Phase 1 of Ningbo rail transit line 5, the deformation characteristics, effect, and cost of the different retaining structures are compared, and optimization suggestions are put forward. The results show the following. (1) The deformation curves of both sides of the diaphragm wall are almost the same, showing a concave shape, small at both ends and large in the middle, whereas the multirow steel sheet piles outside the pit show a foot shape, small at top and large at bottom. (2) Compared with the data of the south retaining structure using conventional diaphragm wall, the horizontal displacement of the north retaining structure using composite retaining structure is 7%~24% less, indicating a better support effect. (3) The horizontal displacement at the diaphragm wall bottom is relatively large, but is still within the safe range. (4) The composite retaining structure occupies a small area for cofferdam, which is conducive to protecting adjacent river. (5) The composite retaining structure also has the advantages of convenient construction, short construction period, and higher sustainable economic benefits.