盾构隧道泥渣脱水处理技术研究综述

Review on Dehydration Technology of Shield Tunnel Spoil

脱水处理是盾构泥渣减量化的主要方法,对现阶段各类盾构隧道泥渣脱水处理技术进行分析总结具有重要的意义。从盾构泥渣的性质及其赋存水机制出发,总结归纳过滤比阻、毛细吸水时间、沉降速率、渗透系数以及含水率5项用于评价泥渣脱水性能的指标,重点阐述机械脱水、干化脱水与渗流脱水等主要脱水技术,分析各类方法的脱水效果、适用性和局限性。机械脱水技术在黏粒含量较少的盾构泥渣脱水处理方面已较为成熟,而对于黏粒含量较多的盾构泥渣需加入高效的调理剂改性以增强脱水性能,目前较高的脱水成本与调理剂污染处理是其亟需解决的问题。自然晾晒显然已不能满足效率与环保的要求;热干化脱水虽然适用范围广且脱水较为彻底,但其存在能耗大、成本高的缺陷;渗流脱水技术中的土工管袋法以及真空预压法对渗透性较大的泥渣具有较好的脱水效果;电渗法可适用于低渗透性黏土,然而其耗电量大且电极易腐蚀的缺陷还难以避免。目前盾构泥渣脱水处理主要存在设备适应性不足、能耗高与运维难、泥渣资源利用率低、新技术难以推广应用以及处理规范体系不完善等问题。未来应注重脱水设备向智能化、模块化、集成规模化三位一体方向的发展,同时实现高效的泥渣资源再利用,制定统一的脱水规范并鼓励脱水新技术的工程应用与推广。

Dehydration technology is the main method of shield tunnel spoil reduction,and it is of great significance to analyze and summarize various dehydration technologies of shield tunnel spoil at the present stage.Based on the nature of shield tunnel spoil and its water retention mechanism,five indicators for evaluating spoil dehydration performance,including specific resistance to filtration,capillary suction time,sedimentation rate,permeability coefficient,and water content are summarized.Three main types of dehydration technologies are expounded emphatically,namely,mechanical dehydration,drying dehydration,and seepage dehydration.Furthermore,the dehydration effects,applicability,and limitations of various methods are analyzed.The mechanical dehydration technology is relatively mature for shield tunnel spoil with low clay content.High-efficiency conditioners shall be added to enhance dehydration performance for shield tunnel spoil with high clay content.Currently,the high cost and pollution treatment of conditioners are urgent issues that must be solved.Natural drying evidently falls short of meeting the requirements on efficiency and environmental sustainability.Although dehydration by heat drying has a wide range of applications and is relatively complete,it has the disadvantages of high energy consumption and cost.In the seepage dehydration technology,the geotextile tube bag method and the vacuum preloading method exhibit superior dehydration effects for spoil with high permeability.The electroosmosis method can be applied to low-permeability clay.However,its drawbacks,such as high power consumption and susceptibility of electrode corrosion,can hardly be avoided.Currently,the main issues in dehydration of shield tunnel spoil include insufficient equipment adaptability,high energy consumption,difficulty in operation and maintenance,low utilization rate of spoil resources,challenges in promotion and application of new technologies,and incomplete treatment standards.In the future,emphasis should be placed on the intelligentization,modularity,and integrated and scaled development of dehydration equipment.Meanwhile,efficient utilization of spoil resources should be achieved.Unified dehydration standards should be established,and efforts should be made to encourage engineering application and promotion of new dehydration technologies.