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针对目前真空预压法加固吹填土地基中存在的真空传递效率低,排水板易淤堵,深层土体排水固结困难,工期较长的问题,提出一种新型化学絮凝联合真空预压法,其方法在于加固前,先在吹填土样中加入一种化学药剂,通过有效的化学絮凝作用使细小土颗粒凝聚成团,同时降低土颗粒黏性,增大渗透性以利于排水,之后再采用真空预压进行加固处理。为此,设计一组絮凝剂在不同掺量下的真空预压室内模型桶试验,结果表明,掺入絮凝剂的吹填土土中真空度明显上升,孔隙水压力下降更多且消散速率更快,出水量趋于稳定所需时间大大缩短,十字板强度大幅度提升,且沿深度递减幅度大为减小,证明采用絮凝联合真空预压法能使吹填土获得更好的加固效果;絮凝剂的使用存在一个最佳掺量,掺量过多或过少都不能使吹填土加固效果达到最优;通过加固后的效果对比,得到温州地区吹填淤泥(含水量300%)的絮凝剂最佳掺量为1.5%。
Aiming at the existing problems of vacuum preloading, such as low vacuum transfer efficiency, easy drainage of drainage board, difficulty of drainage and consolidation in deep soil, and long construction period, a new type of chemical flocculation combined with vacuum preloading method , The method consists in adding a chemical agent into the dredged soil sample before the reinforcement, so that the fine soil particles agglomerate into a mass through effective chemical flocculation, meanwhile reducing the viscosity of the soil particles and increasing the permeability to facilitate drainage, and then Then use vacuum preloading for reinforcement. For this reason, a series of experiments of vacuum preloading indoor model barrels with different dosage of flocculant were designed. The results showed that the vacuum degree of the dredged soil with flocculants increased obviously, the pore water pressure dropped more and the dissipation rate was more The time required for the water to stabilize quickly and quickly, the strength of the cross-shaped plate increased greatly, and the decreasing extent along the depth greatly reduced, which proves that the combined effect of flocculation and vacuum preloading can make the dredged soil get a better reinforcement effect; Flocculant used in the presence of an optimal dosage, the amount of too much or too little can not make the effect of the dredging fill to achieve the best; through the comparison of the effect of reinforcement, get the Wenzhou area dredging mud (water content 300%) The best dosage of flocculant is 1.5%.