城市河道淤泥特性及改良试验初探

以南京内秦淮河疏浚淤泥为例，通过土工试验、XRD和X射线荧光光谱试验等方法，研究了城市河道淤泥的物理性质、矿物成分、化学成分等特性。试验结果显示:秦淮河淤泥粘粒含量低、有机质含量极高，矿物成分主要有石英和少量粘土矿物等。为了实现淤泥的资源化处理，运用水泥、石灰无机固化材料对淤泥进行固化改良试验及改性土无侧限抗压强度试验，结果表明随着水泥掺量增加，水泥固化土由塑性破坏向脆性破坏过渡，破坏应变在1.8%~2.2%，而石灰固化土均表现为脆性破坏，且破坏应变小于水泥土，为1%左右。水泥固化土28d强度为670kPa，固化效果优于石灰，但略低于处理一般软土的固化土强度。研究结果对处置城市河道淤泥有一定参考价值。

A study on the properties and modification test of the dredged material of an urban river

The dredged material (DM) of Qinhuai River, Nanjing, was taken as an example. Through the basic geotechnical tests with XRD and X ray fluorescence spectrometer, the basic physical properties, mineral composition, chemical compositions of the material were studied, respectively. The results show that the DM of the Qinhuai River has a very low content of clay, its organic matter content is very high; mineral composition are mainly composed of quartz and clay minerals. In order to study resource reusing treatment of DM，cement and lime were added to solidify the soil for comparison. The unconfined compressive strength (UCS) tests indicate that with the increasing cement content, the failure of cement solidified soils are converted from plasticity to brittle in failure strain of 1.8% to 2.2%，while all the lime solidified soils of about 1%.The UCS value of 28d cement solidified soil is only 670 kPa. The curing effect of cement is better than that of lime, but its strength is lower than the cement solidified strength of general soft clay. The research result is beneficial to the disposal of DM of urban river.