城市河道淤泥基本土工特性与资源化利用对策——以南京市内秦淮河中段为例

Basic Geotechnical Characteristics and Resource Utilization Countermeasures of Urban River Sediments:Taking the Middle Section of Inner Qinhuai River in Nanjing as an Example

为了掌握城市河道淤泥的基本土工特性,以南京市内秦淮河中段为例,在河段上游、中游、下游分别采集S、Z、X淤泥,开展了矿物成分分析、化学成分分析、热重差热分析、基本物理性质试验、击实试验、压缩试验、直剪试验等。结果表明:1)淤泥以石英为主要矿物,黏土矿物以伊利石为主,化学成分以SiO_(2)、Al_(2)O_(3)、CaO为主。2)从研究区域的上游到下游,S、Z、X淤泥有机质含量从7.7%增加到14.2%,土体相对密度从2.58减小到2.39,砂粒含量明显增加,粉粒含量逐渐下降,黏粒含量略有下降,平均粒径逐渐增大,S、Z淤泥级配良好,X淤泥级配不良。3)随着有机质含量的增加,城市河道淤泥最大干密度逐渐降低,最优含水率逐渐增加,压缩性逐渐增加,均为中等压缩性土。以上研究为城市河道淤泥的填埋处置及资源化利用提供了参考。

In order to understand the basic geotechnical characteristics of the urban river sediments,taking the middle section of inner Qinhuai river in Nanjing as an example,S,Z and X sediments are collected in the upper,middle and lower reaches of the river section respectively.Their mineral composition,chemical composition,thermogravimetric differential thermal,basic physical properties,compaction characteristics,compression and shear strength are investigated.The results show that:1)the main mineral composition and clay mineral composition are Quartz and Illite,respectively.The chemical composition is mainly SiO_(2),Al_(2)O_(3) and CaO.2)From the upstream to the downstream of the study area,the organic matter content of S,Z and X sediments increases from 7.7%to 14.2%,the relative density of soil decreases from 2.58 to 2.39,the coarse sediments content obviously increases,the powder content gradually decreases,the clay content slightly decreases,and the average particle size gradually increases.S and Z sediments are well graded,and X sediments is poorly graded.3)As the organic matter content increases,the maximum dry density of urban river sediments decreases,the optimal water content increases,and the compressibility increases,all of which are medium compressible soils.The research conclusions can provide a reference for the landfill disposal and resource utilization of urban river sediments.