着重阐论南昆线七甸泥炭土(泥炭、泥炭土的合称)的物质成分、微结构特征及泥炭土的物理力学性质,探讨物质成分、微结构特征对物理力学性质的影响。 The paper mainly focuses on the material composition, microstructure characteristics and peat soil physical and mechanical properties of peat soil (collectively named as peat and peat soil) on the Qiantian Pedestal in Nanking-Kunming Railway. The physical and mechanical properties of peat soil are also discussed. The effects of material composition and microstructure on physical and mechanical properties are also discussed.