基于药剂真空预压法工程废浆的物质组构演化机理及固结模型研究

Construction waste slurry in direct emissions often leads to serious environmental pollution and social issues. Traditional vacuum preloading method cannot reach the ideal effect because of the geomembrane clog. The additive agent combined vacuum preloading method is feasible, However, the anti-clogging and consolidation mechanism is still unclear. This project focus on agents effect, anti-silt blocking mechanism and mud flocs large deformation consolidation problems. Based on the laboratory test, the sedimentation column test and the microstructure test, the evolution mechanism of the material composition in the slurry after the addition of the agent was revealed. Based on gradient ratio test and microstructure test methods, the mechanism of anti - siltation in mud flocs was carried out. The criterion of mud flocculation was built. The mechanism of soil particle migration and the formation mechanism of "soil column" in the process of large deformation vacuum consolidation are measured through transparent soil model test method. Based on the consolidation test data of the floc, the relationship between the large deformation and consolidation parameters is determined, and the large deformation vacuum consolidation model and calculation method for the mud flocs after the treatment are established. The results can improve and innovate the calculation theory of vacuum preloading method treat engineering waste slurry. It has important application value and social and economic benefit to the design and construction on waste slurry based on vacuum preloading with flocculants.

工程废浆直接排放易引发严重的环境污染问题和社会问题，常规真空预压法由于过滤膜容易被淤堵而无法达到有效的处理效果；药剂真空预压法可以有效防止淤堵，但其防淤堵机理和固结计算理论并不清晰。本课题拟围绕药剂作用、防淤堵机理和泥浆絮体大变形固结等问题开展研究。基于室内土工试验、沉降柱试验及微观结构试验等手段，揭示加入药剂后泥浆中物质组构的演化机理；通过梯度比试验、微观结构试验研究药剂真空预压处理泥浆絮体中的防淤堵机理，提出适用于泥浆絮体的反滤准则；在模型试验中引入透明土试验技术，可视化探讨大变形真空固结过程中土颗粒的迁移规律和“土柱”的形成机制；结合泥浆絮体的固结试验数据，确定大变形固结参数之间的关系表达式，建立适用于药剂处理后泥浆絮体的大变形真空固结模型及计算方法。研究成果将丰富真空预压法处理工程废浆计算理论；对指导药剂真空预压法处理工程废浆工程设计、施工具有重要的应用价值和社会经济效益。

在城市地下工程施工过程中所产生的废弃泥浆是一种稳定的悬浊体系，直接无序排放会造成当地环境的极大污染，对其进行无害化处理已经成为目前城市建设中亟待解决的重要问题之一。药剂真空预压法是将药剂絮凝与传统真空预压相结合处理工程废弃泥浆的一种有效方法，本项目针对废弃泥浆中絮凝药剂的骨架构建作用、不同无机药剂对工程废浆药剂真空预压的影响、pH 值对工程废浆稳定、絮凝及固结特性的若干影响，以及掺入不同絮凝药剂时高黏粒含量的废浆渗透性和真空固结特性进行了研究。特别是首次将透明土试验技术引入超软土（泥浆）真空预压处理中，开展了超软土真空预压透明土模型试验，非嵌入式地可视化监测了真空预压过程中排水板周围土体位移场，揭示了超软土真空预压的淤堵机理，以及形成土桩和“软弱带”现象的主要原因。将药剂真空预压法引入到城市市政污泥原位处理中，提出Fenton试剂、FeCl3等药剂联合真空预压的方法，取得了有效的快速排水固结作用，为市政污泥的原位处理提供了一种可行的现场处理方法。