药剂掺量对高黏粒含量废浆渗透性和真空固结特性的影响

Effects of new chemicals on permeability and vacuum consolidation of waste pulp in high clay content

针对温州某工程产生的高含水率、高黏粒含量废浆,通过添加掺量不同自主配置的固化混凝剂,进行了自由沉降和一维固结试验,研究掺量与颗分、浊度、p H值、浑液面沉降以及液塑限的关系,并通过真空排水模型试验,研究药剂掺量对渗透特性和强度的影响.研究结果表明:(1)药剂通过压缩双电层将废浆中的细小颗粒聚并,但是小颗粒减少的程度不如有机药剂显著;(2)加入药剂后3或7 d时,废浆渗透系数比较大,小于或大于该龄期时渗透系数均会减小;(3)药剂掺量越多,浆体渗透系数越大,在低固结压力区间可提高为原来的5~10倍;(4)药剂和真空排水相结合可以大幅提高真空排水速率,在降低含水率的同时,提高土体液塑限和土体强度,试验中十字板剪切强度最高达47.1 k Pa.研究结果表明,新型药剂对于真空预压处理废浆的作用主要体现在颗粒聚并、增渗增排和固化,通过选择适当的药剂掺量和龄期可以获得显著的处理效果,值得大范围推广.

For Wenzhou waste pulp with high contents of water and clay,we study relationship between agent dosage and particle composition,turbidity,pH,muddy surface subsidence and liquid plastic limit in a free settling and one-dimensional consolidation test by adding different doses of curing flocculation.Effects of agent dosage on permeability and strength are also studied in a vacuum drainage model test.The following results are obtained.1)The chemicals coalesce small particles by compressing twin electrical layer,but the degree is less than organic chemicals.2)Waste pulp permeability coefficient becomes large in 3 or 7 days after the agents join in,decreases in other time.The reagent dosage and slurry permeability coefficient is large.In a range of low consolidation pressure,it can increase 5~10 times as compared to the original waste pulp.3)Chemicals with vacuum drainage can greatly improve the combination of vacuum drainage rate.In low water content at the same time,the strength,plastic limit,and liquid limit of the soil are increased.Test of vane shear strength is up to 47.1 kPa.The analysis shows that the effects of new chemicals on waste pulp by vacuum preloading mainly embodied in particle coalescence,increase permeability and increase drainage,and curing.By selecting appropriate chemical dosage and ages,significant treatment effect can result.It is worth of large scale promotion.