南京河西地区软土地层特征及工程特性研究

Research on Engineering Properties of Floodplain Soft Soil in Hexi Area,Nanjing

南京河西地区软弱土层性质复杂。为对工程建设提出针对性的设计和治理措施,有必要对该地区软弱土层成因及工程特性进行全面、系统的研究。本文主要针对河西地区地层结构及沉积演化特点,对软弱土层的物质成分、微结构特征以及土的渗透、压缩、强度、灵敏度和蠕变特性进行了分析。结果表明河西地区软弱土层属于河漫滩沉积,其沉积过程与河道变迁密切相关,具有沉积年代新、结构成熟度低、厚度变化大、土层分布不均并夹有砂透镜的特点。软弱土层属于欠固结土,粘土矿物以伊利石为主,具有中等—高灵敏性和低—中等次固结特性。

The complex properties and genetic origin of soft soil in the Hexi area（west of the Qinhuai River） of Nanjing City need to be conducted with a comprehensive and systematic research in order to propose reasonable design and management measures for the constructions.In this paper,the sedimentary evolution of stratigraphic features,the micro-structure and material composition of the soft soil,as well as the infiltration,compression,strength,sensitivity and creep properties were analyzed.It could be shown that the floodplain deposition environment and process of soft soil stratum in Hexi district were mainly closely related to the changes of river valley,which were deposited with a new age,with structures of low maturity,large variation of thickness,uneven distribution of sand interbed lens.Such type of soft soil could be concluded as underconsolidated mainly with clay minerals of illite,medium—high sensitivity and low—medium secondary consolidation characteristics.