无机药剂对工程废浆药剂真空预压的影响

针对温州某工程施工过程中产生的高含水率废弃泥浆，预添加不同种类与掺量的无机化学药剂，使泥浆与药剂充分发生化学反应，然后进行了20组废浆的真空预压模型试验，试验中对废浆排水量、含水率、液塑限、颗粒组成、十字板剪切强度和微观结构进行了测试，研究不同无机药剂对工程废弃泥浆药剂真空预压效果的影响。研究结果表明：药剂预调理可以将泥浆中细小颗粒聚集成粒径较大的颗粒体，具有改善泥浆渗透性和加快排水速率的作用，达到相同排水量时所需时间比不加药剂要减少近1/2；药剂真空预压处理可以将泥浆含水率由180%降低至50%~60%，且加入药剂能提高成泥浆土的液塑限，大幅度提高土体强度，处理后其十字板剪切强度可达30~50 kPa；由扫描电镜微观结构图像分析可知，与添加单一药剂相比，预添加混合药剂的泥浆真空排水后土颗粒团聚现象显著，排列更加紧密，孔隙更小，整体性更好，十字板剪切强度也印证了这一点；根据药剂对废浆特性影响的特点，从理论上对药剂真空预压机理进行了解释，认为药剂真空预压处理废浆中包含"黏塑性流体颗粒聚并"和"黏塑性流体固化"2种作用机理；可见采用适当掺入比例的多种无机药剂组合对废弃泥浆进行药剂真空预压处理能够获得较好的处理效果。

Effect of Inorganic Chemicals on Vacuum Preloading with Flocculation of Construction Waste Slurry

In this study, mud with a high water content in a pile foundation project in Wenzhou is analyzed by adding different types of chemicals. Twenty groups of vacuum consolidation experiments are performed. The water content, liquid plastic limit, particle composition, vane shear strength, and microstructure are tested in these experiments. The test results are as follows:With chemical pretreatment, the tiny particles in the mud are assembled into larger particles, which improve the permeability and accelerate the consolidation of mud. Moreover, the time is also reduced by nearly half. After the chemical-vacuum preloading, the water content is reduced from 180% to 50%-60%. Adding the chemicals improves the liquid and plastic limit of the soil and also the soil strength up to 30-50 kPa. From the analysis of the electron microscope scanning images, the particles of the soil samples, which were improved by lime combined with the vacuum preloading treatment, present a better noticeable agglomerate phenomenon. The improved soil samples have a better integrity with smaller pores. This is also supported by the vane shear test. Based on the effects of the chemicals on the mud properties, two types of mechanisms are found, including the "viscoplastic fluid particle coalescence" and "viscoplastic fluid curing". The study shows that chemical-vacuum preloading has a significant effect on treatment, particularly for various inorganic reagent combinations.