地下非饱和土壤中水分水平扩散的试验探究和模型拟合

Experimental investigation and model simulation ofhorizontal diffusion of water in underground unsaturated soil

非饱和土中水分的运移研究在实际的修复工程中具有重要的理论指导作用。为了研究在修复工程中遇到的药剂溶液在污染土中的扩散问题,本文利用自制室内试验设备进行了药剂溶液在非饱和土柱的水分水平扩散模拟试验,研究土压(围压)对水分在土中扩散能力的影响。试验结果表明,围压对水分扩散的影响是先促进后抑制的。在此基础上,采用分形理查兹方程(FRE)模型拟合含水率曲线。结果表明,FRE模型对本组室内扩散试验有较好的拟合效果,为地下非饱和土中溶液扩散的模拟提供了模型支持。同时,利用反映物理意义的拟合参数的变化分析了实验规律及现象的机理。

The study of water transport in unsaturated soil has an important theoretical guiding role in practical remediation projects.In order to study the diffusion of agent solutions in contaminated soil during remediation project,the simulation experiments of water transport in unsaturated soil column were carried out with self-made laboratory test equipment,and the influence of confining pressure on the diffusion ability of agents in soil was studied.The results show that the influence of confining pressure on water diffusion is first promoted and then suppressed.On this basis,the fractal Richards equation(FRE)model was used to fit the water curve.The results show that the FRE model has a good fitting effect for the laboratory diffusion experiments in this group,and provides model support for the simulation of solution diffusion in underground unsaturated soil.At the same time,the change of fitting parameters reflecting physical meaning was used to analyze the experimental law and the mechanism of phenomena.