脱硫灰-水泥固化淤泥强度特性与固化-抽滤联合加固应用

Strength characteristics of stabilized sludge by desulphurization ash and cement and application of stabilization-vacuum filtration method

采用水泥-脱硫灰复合体系固化淤泥软土,进行液塑限、无侧限抗压强度、扫描电镜、能谱分析等一系列实验,分析多种脱硫灰质量分数下固化土的物理力学行为.鉴于脱硫灰能明显抑制黏土亲水性,引入了真空抽滤工艺,并进行了水泥-脱硫灰就地固化与真空抽滤的现场对比实验.结果表明,脱硫灰的加入会使土的液限和塑性指数显著下降.脱硫灰与水泥质量比为20%时固化土强度最高.脱硫灰质量分数过高时,产生的强碱高钙环境抑制了黏土矿物水膜,导致结合水减少,自由水增多,固化土强度随之下降.真空抽滤工艺配合脱硫灰则可大幅度减少土中自由水含量.脱硫灰与真空抽滤联合具有良好的加固效果,可应用于浅层高含水率淤泥处理中.

Experiments including Atterberg limit,unconfined compressive strength,scanning electron microscope(SEM)and energy-dispersive X-ray spectroscopy(EDS)were performed on the sludge stabilized by cement and desulphurization ash(DA)composite.The phyco-mechanical behaviors and microstructures of stabilized sludge with different mass fractions of DA were analyzed.Since DA can significantly inhibit the hydrophilicity of clay,a vacuum pumping process was introduced.Field comparative tests of in-situ curing and vacuum filtration were carried out.The results show that the addition of DA can significantly reduce the liquid limit and the plasticity index of stabilized sludge.The soil strength is the highest when the mass ratio of DA to cement is 20%.When the mass fraction of DA is excessive,the strong alkali and high calcium environment inhibits the clay mineral water film,resulting in a decrease in bound water and an increase in free water.Therefore,the strength of the solidified soil decreases.The vacuum filtration process combined with the incorporation of DA can greatly reduce the content of free water in the sludge.Combination of DA addition and vacuum filtration has a good reinforcement effect and can be used in the treatment of shallow sludge with high moisture content.