为更加精细化地指导大断面异形盾构隧道施工注浆荷载下的结构设计工作，依托宁波地铁3号线类矩形盾构隧道工程，探索施工荷载注浆工况下衬砌结构的受力特征，研究同步注浆填充阶段真实的浆液扩散过程及其压力分布规律，针对既有设计模型中注浆工况下的荷载施加模式、注浆填充扩散压力分布计算模型以及特殊工况下的实际受荷情况进行综合分析。结果表明： 按注浆填充扩散压力分析的结构受力较为均匀，而既有设计模型注浆工况和特殊条件下的荷载分布会使得管片结构受力更加不利，建议在类矩形盾构衬砌结构注浆工况设计模型中考虑浆液环向填充扩散机制对应的结构受力模式为基础，在拱顶、拱肩、拱腰及拱底处分别叠加100、150、200、250 kPa的分布压力较为合适。

To more finely guide the structural design of largecrosssection specialshaped shield tunnel under the corresponding construction grouting load, a case study is conducted on the quasirectangular shield tunnel project of Ningbo metro line 3. The stress characteristics of the lining structure under construction load and grouting conditions are explored, and the real grout filling and diffusion processes and its pressure distribution law during synchronous grouting are investigated. Finally, a comprehensive analysis is conducted on the loading mode under grouting condition in the existing design model, the grout filling diffusion pressure distribution calculation model, and the pressure distribution pattern under special conditions. The results reveal the following: (1) The structural force is more uniform according to the grout filling and diffusion pressure analysis. (2) The structural force of the pipe is more unfavorable under grout filling conditions of the existing design model and load distribution under special conditions. (3) It is recommended to consider the structural force pattern corresponding to the grout circumferential filling and diffusion mechanism in the design model, and superimpose distributed pressures of 100 kPa, 150 kPa, 200 kPa, and 250 kPa at the crown, arch shoulder, waist, and bottom respectively.