ERT与染色示踪方法在土壤入渗监测中的应用

发布时间：2018-04-28 14:34

本文选题：土壤 + ERT　；参考：《青岛大学》2017年硕士论文

【摘要】：大气降水入渗到地下转化成土壤水,土壤水经由非饱和带(或渗流带)到达地下水面,补给地下水。土壤水和地下水是干旱半干旱地区水资源最重要的组成部分,它们支撑着该地区工业、农业、生活及生态需水。为了保证水资源的可持续利用,需要准确地估计地下水补给量(或速率)。近年来,随着经济的发展和人民生活水平的提高,青岛市水资源日益匮乏。大沽河作为青岛市的重要水源地,虽然流域面积广阔,但面临着地下水位下降、海水入侵和地下水污染等诸多问题,而探究土壤水入渗过程是研究这些问题的关键之一。近二十年来,高密度电阻率成像法(ERT)作为一种新兴的水文地球物理技术,因其非破坏性、时空连续性和高分辨率等特点在土壤水分入渗研究中得到广泛应用,而染色示踪试验由于能清晰、直观地反映土壤水分流动路径而受到人们的关注。为了解水分在土壤中的运动过程,本文共进行了室内土壤水分入渗实验和田间土壤水分入渗试验两个部分,分析了在不同入渗量条件下,均质土壤和非均质土壤中水分的运动过程。室内土柱水分入渗实验过程中,采用土壤水分传感器作为监测装置,将其安装于土柱的不同深度处,监测不同入渗水量时剖面含水量变化情况,并利用不同的模型模拟水分的运动。田间水分入渗试验于大沽河下游的即墨市蓝村镇四里村农田进行,布设2~4条测线,采用类似于双套环的试验装置,在测线中央插入尺寸为0.5 m×0.5 m×0.5 m的铁框(内框)和1.2 m×1.0 m×0.8 m的有机玻璃框(外框),内框中注入3.0 g/L的亮蓝溶液,外框内注入同等高度的水,在内外框水头高度都是3.0 cm的条件下,亮蓝溶液和水分都会向下入渗。利用DCX-1G多功能高密度电法仪—实时成像系统(ERT)原位监测水分和亮蓝溶液入渗前、入渗过程中及入渗后的电阻率变化。将二维剖面电阻率信息整理并导入到三维Voxler软件中,实现由二维到三维图像的转换,以便更加清晰地观察土壤水分入渗过程,并用Hydrus-1D软件模拟土壤水分运动,以便进一步验证ERT监测土壤入渗过程的可行性。在试验结束后,对铁框范围内的土壤沿东西方向每隔5~10 cm开挖剖面,一直开挖至无法看到染色示踪剂为止,并用数码相机记录剖面的染色状况。本文的研究得出以下几点结论:(1)通过对室内土柱入渗实验的分析,发现水分在入渗开始时的入渗率较大,累积入渗量的变化较快;随着时间的推移,入渗率逐渐减小并趋于稳定。室内实验的入渗过程可用Philip模型和Kostiakov模型进行模拟,Kostiakov模型的拟合度优于Philip模型;入渗过程和再分布过程均可用Hydrus-1D模拟,它对前者的模拟结果较好,但对后者的模拟结果稍差。(2)根据ERT反演后计算得到的电阻率值,将其与实测的含水量数据用改进后的Archie公式拟合,获得了含水量与电阻率之间的定量关系,其拟合度为0.765,相关性较好,能较为准确地反映含水量与电阻率之间的关系。(3)利用ERT监测田间土壤水分运动时,在入渗初期,入渗区域土壤的表层电阻率迅速降低,随着时间的延续,表层电阻率的变化逐渐减小;比较试验不同时刻土壤水分入渗剖面和亮蓝溶液入渗剖面,发现土壤水分的入渗速度比亮蓝溶液的入渗速度要快;在亮蓝溶液入渗的过程中,由于上部土壤会对亮蓝溶液产生吸附,所以在优先流区域引起电阻率变化的主要原因是水分的运动;在入渗量特别大时,水分会在渗透性较差的区域产生积聚。(4)将系列二维电阻率剖面信息导入到Voxler软件转换成三维空间电阻率分布模型,得到了更加丰富的地电断面信息,可以更清晰地反映土壤水分入渗过程。通过将二维电阻率剖面信息与三维电阻率立体信息相对比,发现三维电阻率模型能够准确地反映土壤水分运动过程。(5)利用Photoshop图像处理软件将入渗试验结束时的土壤染色剖面图像处理成为二值图像,并统计分析土壤剖面染色比例在垂直方向上的变化,发现随着入渗量的增大,亮蓝的最大染色深度、均匀染色范围、优先流的均匀程度都随之增加。
[Abstract]:The atmospheric precipitation is converted into soil water, and the soil water flows through the unsaturated zone (or percolation zone) to the surface of the surface of the water to recharge the groundwater. Soil water and groundwater are the most important components of the water resources in arid and semi-arid areas. They support the industrial, agricultural, living and ecological water requirements of the region. In recent years, with the development of the economy and the improvement of the people's living standards, the water resources in Qingdao have become increasingly scarce. The Dagu River, as an important source of water in Qingdao, is facing many problems, such as the decline of the groundwater level, the invasion of the sea water and the pollution of the groundwater, and so on. The infiltration process of soil water is one of the key factors to study these problems. In the past twenty years, high density resistivity imaging (ERT), as a new hydrogeophysical technique, has been widely used in the study of soil water infiltration because of its non destructive, spatio-temporal continuity and high resolution, and the dyeing tracer test is clear because of its characteristics. In order to understand the path of soil water flow directly, people pay attention to it. In order to understand the movement process of water in the soil, two parts of the laboratory soil water infiltration experiment and field soil water infiltration test were carried out. The movement process of water in homogeneous soil soil and heterogeneous soil under different infiltration conditions was analyzed. In the process of soil column water infiltration experiment, the soil moisture sensor is used as a monitoring device, which is installed at different depths of the soil column, monitoring the change of water content in the section of different infiltration water, and using different models to simulate the movement of water. Field water infiltration test in the four Li village of blue village in the lower reaches of Jimo River in the Dagu River A 2~4 line is set up, and a test device similar to a double ring is used to insert an iron frame (inner frame) of 0.5 m * 0.5 m x 0.5 m and 1.2 m x 1 m x 0.8 m in the center of the test line. The inner frame is injected with a brilliant blue solution of 3 g/L, and the same height of water is injected into the outer frame, and the height of the head of the inner and outer frame is 3 cm At the same time, the solution and water of the bright blue will be infiltrated downward. The resistivity changes in the infiltration process and after infiltration are monitored in situ using the DCX-1G multi-function high-density electric instrument and real-time imaging system (ERT). The two-dimensional profile resistivity information is arranged and introduced into the 3D Voxler software to realize the two-dimensional to three-dimensional images. The soil moisture infiltration process is more clearly observed and the soil moisture movement is simulated with Hydrus-1D software to further verify the feasibility of ERT monitoring the infiltration process of soil. After the test, the soil in the iron frame range is excavated every 5~10 cm along the east-west direction and is excavated until the stain tracer can not be seen. So far, the dyeing status of the section is recorded with a digital camera. The following conclusions are drawn as follows: (1) through the analysis of the laboratory soil column infiltration experiment, it is found that the infiltration rate of water in the beginning of infiltration is larger and the change of the cumulative infiltration amount is faster; the infiltration rate gradually decreases and tends to stability as time goes on. The infiltration of indoor experiments The process can be simulated with Philip model and Kostiakov model, and the fitting degree of Kostiakov model is better than that of Philip model. The infiltration process and redistribution process can be simulated with Hydrus-1D. The simulation results of the former are better, but the simulation results of the latter are poor. (2) the resistivity values obtained by the ERT inversion can be calculated with the measured water content. The quantitative data is fitted with the improved Archie formula. The quantitative relationship between water content and resistivity is obtained. The fitting degree is 0.765, the correlation is better, and the relationship between water content and resistivity can be accurately reflected. (3) when soil moisture movement in the field is monitored by ERT, the surface layer resistivity of the infiltration area is rapid in the infiltration area. As time continues, the change of surface resistivity decreases gradually, and the infiltration velocity of soil moisture is faster than that of bright blue solution at different time, and in the process of bright blue solution, the adsorption of bright blue solution will be produced in the process of bright blue solution infiltration. The main reason for the change of resistivity in the preferential flow region is the movement of water. When the infiltration amount is very large, the water will accumulate in the region with poor permeability. (4) the series of two-dimensional resistivity profile information is transferred into the Voxler software to transform into a three-dimensional spatial resistivity distribution model, and a more abundant geoelectric section information is obtained. In order to reflect the infiltration process of soil moisture more clearly. By comparing the two-dimensional resistivity profile information with three-dimensional resistivity stereoscopic information, it is found that the three-dimensional resistivity model can accurately reflect the soil moisture movement process. (5) the soil dyeing section image of the infiltration test junction is processed into two by using the Photoshop image processing software. The change in the vertical direction of the soil section dyeing ratio in the vertical direction is statistically analyzed. It is found that with the increase of infiltration, the maximum dyeing depth of the bright blue, the uniform dyeing range, and the uniformity of the preferential flow increase.

【学位授予单位】：青岛大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S152.72

【参考文献】