Abstract

The dredged clay (DC) could not be directly reutilized for its extra-high water content. So, the dewatering is needed before further improvement. At present, the commonly used self-weight sedimentation and natural air-drying are often difficult to meet the engineering requirements and time-consuming, thus chemical flocculants are used to improve the dewatering process for their excellent flocculation in recent years. In this study, the flocculant effects on the fluidity and strength behavior of cement-treated dredged clay, are investigated based on experimental results. For the dredged clay, its fluidity firstly increases with the increasing content of FeCl₃ and Chitosan, and then reaches a stable value; while the addition of PAM would decrease its fluidity. Compared with the dredged clay, relatively small changes in the fluidity of solidified dredged clay are found with the addition of flocculants. The flocculant with a suitable dosage has an overall enhancement in the undrained strength of solidified soils. The flocculation of dredged clay/cemented clay induced by the flocculant is responsible for changes in the fluidity and undrained strength. For flocculants used in this study, the appropriate content corresponding to the target fluidity and maximum strength is in the range of 0.1% to 0.5%.

摘要

疏浚粘土（DC）由于其超高的含水量而不能直接再利用。因此，在进一步改进之前需要进行脱水。目前常用的自重沉降和自然风干往往难以满足工程要求且耗时长，因此近年来化学絮凝剂因其优异的絮凝效果而被用于改进脱水工艺。在本研究中，基于实验结果研究了絮凝剂对水泥处理的疏浚粘土的流动性和强度行为的影响。对于疏浚粘土，其流动性首先随着FeCl ₃含量的增加而增加和壳聚糖，然后达到稳定值；而加入PAM会降低其流动性。与疏浚黏土相比，添加絮凝剂后固化疏浚黏土的流动性变化相对较小。合适用量的絮凝剂对固化土的不排水强度有整体的提高。絮凝剂引起疏浚粘土/胶结粘土的絮凝是造成流动性和不排水强度变化的原因。对于本研究中使用的絮凝剂，对应于目标流动性和最大强度的合适含量在 0.1% 至 0.5% 的范围内。