中文摘要：

南京地铁西延线位于长江漫滩饱和软粘土地层中,地铁施工完成后隧道结构出现了较大的沉降和差异沉降.本文首先提出了可能导致地铁结构产生沉降变形的因素有四个：施工因素、地质因素、堆载因素以及降水因素,然后详细分析了每个因素对隧道结构下沉的影响程度,找出了隧道结构产生沉降和不均匀沉降的主要原因.

英文摘要：

Obvious and different settlements happened in the west extension of the subway that is located in the stratum of Yangtze River valley flat after the construction of the subway tunneling. This paper proposes the reason why the subway structure generated the obvicus subsidence, probably due to four factors： construction factor, geological factor, loading factor and dewatering factor. Furthermore, the paper expounds the degree of settlement which was affected by each factor under the subway structure, and summaries the main reason of the obvious subsidence.