基于液态沉积成型3D打印的裂隙介质复刻方法构建与VOCs迁移研究  

Generation of Reproducible Fractured Media Using Liquid Deposition Modeling 3D Printing and Exploration of VOCs Migration Characteristics

作　　者：马岳勇 王刘炜 侯德义[1] MA Yueyong;WANG Liuwei;HOU Deyi(School of Environment,Tsinghua University,Beijing 100084,China)

机构地区：[1]清华大学环境学院,北京100084

出　　处：《环境科学研究》2024年第11期2537-2546,共10页Research of Environmental Sciences

基　　金：国家重点研发计划项目(No.2020YFC1807101)。

摘　　要：物理模拟实验是揭示裂隙介质中渗流及溶质运移规律的重要手段,但由于裂隙介质的复杂性和随机性,构建可复刻的裂隙实验模型成为一项技术难题,3D打印技术的兴起为此提供了新的思路。本文系统梳理了3D打印技术在裂隙模拟实验中的应用现状,构建了裂隙实验模型复刻新方法,并探究了所获模型的特性。首先,针对现有裂隙模型构建方案存在的材料模拟度低、模型强度不足、时间和经济成本高等缺陷,提出具有裂隙岩体模拟度强、个性化定制灵活、可重复性好等优势的液态沉积成型(LDM)3D打印技术。其次,对该技术结合CT扫描构建获得的高精度裂隙实验模型进行物理化学性质分析,裂隙结构测试显示模型裂隙率为5.77%,与实际岩芯裂隙率(5.46%)非常接近;微观形貌分析表明模型表面具有粗糙特性,断面表现出脆性断裂特征,符合实际岩石特征;模型采用陶泥材料打印,矿物组成及元素特征与硅酸盐岩基本一致,该材料可用于模拟此类岩石。最后,以四氯化碳(CCl4)为例,开展挥发性有机物(VOCs)在包气带裂隙介质中的迁移实验。结果表明,在时间上,裂隙介质中气相CCl4浓度逐渐增大并趋于平衡,平衡浓度及平衡时间受污染源(地下水)中CCl4浓度的控制;空间上,裂隙介质中气相CCl4浓度自上而下逐渐增大,平衡状态下气相CCl4浓度呈指数型分布。综上,LDM型3D打印技术能够有效复刻裂隙介质,并可用于VOCs等污染物模拟实验,后续研究需要关注材料创新、应用探索及打印精度提升。Physical simulation experiments are essential for revealing fluid flow and solute transport mechanisms in fractured media.However,the inherent complexity and randomness of such media pose significant challenges in constructing reproducible experimental models.The development of 3D printing technology offers new solutions.This paper first reviewed the current application of 3D printing in fracture simulation and then proposed a novel method for reproducing fracture models and investigating their properties.The main findings are summarized below:First,Liquid Deposition Modeling(LDM)3D printing technology was introduced to address the limitations of existing fractured model construction approaches.Second,physicochemical properties of the high precision fractured experimental models were analyzed.The fracture structure test revealed that the model had a fracture rate of 5.77%,closely matching the actual fracture rate of 5.46%observed in the rock material.Micro-morphology analysis further confirmed the model’s surface roughness and brittle fracture characteristics,demonstrating consistency with actual rock properties.The model was printed using clay material,and its mineral composition and elemental characteristics were largely consistent with silicate rocks.Lastly,an experiment was conducted using carbon tetrachloride(CCl4)as a case study to investigate VOCs migration characteristics in the vadose zone of fractured media.The results indicated that the gaseous CCl4 concentration in the fractured media gradually increased and approached equilibrate over time,with the equilibrium concentration and time being regulated by the CCl4 concentration in the pollution source(groundwater).Spatially,the gaseous CCl4 concentration within the fractured media showed a gradual increase from the top to the bottom,and at equilibrium,the gaseous CCl4 concentration followed an exponential distribution pattern.In summary,LDM 3D printing technology effectively replicated fractured media and is promising for VOCs simulation experiments.Fu

关 键 词：裂隙实验模型 3D打印 液态沉积成型 CT扫描 VOCS 

分 类 号：X523[环境科学与工程—环境工程]