李进军¹，  王卫东¹，  颜洪²
（1  现代设计集团华东建筑设计研究院有限公司，上海200002； 2南昌大学第二附属医院基建科，南昌330006）

[提要] 基于南昌大学第二附属医院医疗中心大楼逆作法工程的成功实践，介绍了新型逆作法结构型式在江西地区的首次应用。本工程采用全逆作法总体设计思路，地上地下结构同步施工，在地下二层逆作施工同时完成地上十层结构的施工。采用结构梁板替代临时水平支撑、结构竖向构件框架柱与临时立柱相结合的一柱一桩竖向支撑、围护结构采用临时围护体的逆作法结构型式。工程实施监测结果表明，地下结构逆作施工对周边环境影响较小，上部结构沉降均匀稳定。本工程新型逆作法设计取得了良好的社会和经济效益，为江西地区类似工程的设计提供了借鉴。
[关键词] 新型逆作法；支护结构与主体结构相结合；结构梁板替代支撑；一柱一桩；钢筋混凝土环梁节点；型钢混凝土变刚度转换结构

Practice and Design of New Top-down Method in the Project of Second Hospital of Nanchang Uruversity
Li Jinjun¹,  Wang Weidong¹, Yan Hong²
(1 East China Architectural Design & Research Institute Co. ,Ltd., Xian Dai Architectural Design Group, Shanghai 200002 China; 2 Second Affiliated Hospital of Nanchang University, Nanchang 330006, China)

Abstract: Basing on the successful application of the project of second affiliated hospital of Nanchang university, a new top-down design method was introduced on the base of success application in Jiangxi province firstly. The full top-down excavation method was used in the project, and ten floor structures were built at the process of excavation. The key design techniques of the new top-down method including:1)substituting level bracing system by basement slab; 2)combine the structure vertical supporting column with the temporary vertical shoring; 3)using the temporary fender cast-in place piles as exterior-protected construction in top-down excavation process etc. A series of new techniques, which including the profiled bar-concrete controlled bracing system substituting level bracing system by variable level basement roof slap, concrete ring beam on complex boundary condition, the top-down method of etc were first introduced and practiced in engineering originally. It is proved the new top-down method have a good economy effect and society effect. The method provides a new engineering design choice for the similar projects.
Keywords: new top-down method; substituting level bracing system by basement slab;foundation structure in deep excavation supported with substructure;  single column over single pile; concrete ring beam; profiled bar-concrete controlled bracing systeru