[关键词]
[摘要]
为了研究透水混凝土内部孔隙中渗流及堵塞问题,采用透水混凝土堵塞测试装置模拟降雨初期地表微颗粒透过混凝土的流动规律和分布情况,利用CT扫描技术并结合Avizo软件重构其内部的孔道结构,用CFD中DEM模型(计算流体力学中的离散颗粒模型)对昆明市地表微颗粒通过透水混凝土的过程进行多相流模拟。结果表明:CFD数值模拟得到的结果和实验比较吻合,颗粒粒径范围100~500 μm的地表微颗粒对混凝土有一定程度的堵塞,仍具有较好的透水效果(较高的渗透系数),而100 μm以下加入之后的颗粒堵塞较为显著,且渗透系数基本趋近于0;但更为重要的是通过DEM模拟分析发现0~50 μm的小颗粒通过混凝土时渗流速度缓慢并且部分粘连在孔道壁面导致直径减小影响渗流效果。
[Key word]
[Abstract]
In order to address the problem of pore seepage and plugging in pervious concrete,a pervious concrete plugging test device was used to simulate the flow and distribution of surface micro particles through concrete in the initial stage of rainfall.The pore structure was reconstructed by CT scanning technology and avizo software.The surface micro particles in Kunming were modeled by DEM model in CFD.Particles were simulated by multiphase flow through the process of permeable concrete.The results showed that the CFD numerical simulated results were in good agreement with the experimental results.The surface micro particles with particle size rangeing100~500 μm had a certain degree of blockage to the concrete,and still had a good permeability (higher permeability coefficient).The blockage of particles below 100 μm was more significant,and the permeability coefficient approached to the basic level of zero ;More importantly,it was found that the seepage velocity of 0~50 μm particles passing through concrete was slow and partially adhered to the wall of the tunnel,leading to the decrease of the diameter,which affected the seepage.
[中图分类号]
[基金项目]
云南省教育厅重点实验室专项基金;水利部科技推广计划项目(2014TG2411)