基于电阻率法的人工湿地堵塞区域定位及预报研究

Clogging is a main operational issue associated with purification performance and lifetime of a constructed wetland; precise positioning and prediction of clogging are urgent issues.This study focuses on the resistivity characters of the components and clogging regions within constructed wetlands, and the aim is to achieve the positioning and prediction of the clogging based on the high density resistivity methodand resistivity logging method. The correlation between the hydraulic performance and resistivity will be investigated firstly, and the clogging position could be Identify by the three-dimensional resistivity imaging characters of the constructed wetland.The indexes for predicting clogging are determined by the observed data of four-dimensional resistivity. Ultimately, the clogging prediction system is formed according to the four-dimensional resistivity imaging characters of a constructed wetland. Electrolyte solution (NaCl) will be added in the systems for increasing the resistivities different between the clogging regions and the normal regions. Data acquisition methods will be optimized for enhancing the data acquisition speed. It is intended that the study performed will provide the precise positioning methods for clogging and provide technologicalbasis for preventing clogging.

堵塞是影响人工湿地持久、高效运行的主要障碍，针对人工湿地堵塞区域的精确定位和预报问题亟待解决。本项目以人工湿地构成单元及堵塞区域的电阻率特征为研究对象，以高密度电阻率法和高密度电阻率测井法为研究手段，实现人工湿地堵塞区域的定位与预报。研究从确定人工湿地水力性能与电阻率之间的相关性入手，利用人工湿地三维电阻率成像特征，确定堵塞区域位置；利用四维电阻率观测数据，建立人工湿地堵塞区域预报指标，探讨人工湿地堵塞预报技术，最终建立基于四维电阻率成像特征的人工湿地堵塞预报系统。在研究过程中，为了提高堵塞区域与未堵塞区域的电阻率差异，采用了添加电解质溶液（NaCl溶液）的手段；为了提高电阻率数据采集的速度，将对常规的采集方案进行优化研究。该项目的研究将为人工湿地堵塞区域的快速准确定位提供依据，从而预防堵塞的发生。

堵塞是影响人工湿地持久、高效运行的主要障碍，针对人工湿地堵塞区域的精确定位和预报问题亟待解决。本项目在研究人工湿地流场分布、堵塞物的组分及堵塞物的累计过程的基础上，研究分析了人工湿地构成单元及堵塞区域的电阻率特征，在添加电解质溶液（NaCl溶液）改善堵塞区域与未堵塞区域电阻率差异的前提下，以二维、三维高密度电阻率法、地井综合方法和改进的井中高密度电阻率法为手段，实现了人工湿地堵塞区域的定位与预报。上述研究取得了如下原创性成果：（1）基于MODFLOW建立了人工湿地基质结构定量化设计方法，并据此建立了对比实验系统；（2）饱和状态下不同种类、不同粒径的填料电阻率差异不大，堵塞区域不同发育阶段的电阻率差异也不大，通过添加NaCl溶液可以增大堵塞区域与周围介质之间的电阻率差异，实现堵塞区域的探测；（3）应用有限元方法编制了人工湿地二维和三维的正演模拟程序，应用最小二乘最优化反演方法和统计学建模反演方法进行了人工湿地的二维、三维及地井联合反演，并进行了相应的探测实验；（4）提出并验证了改进的井中高密度电阻率法，可以不用反演即可直接进行三维成像；（5）建立了基于时间序列的四维电阻率成像堵塞预报系统。上述研究成果，证明了电阻率可以有效探测和预报人工湿地堵塞区域，从而为人工湿地持久、高效运行提供保障。