潮土区农田土体构型层次的探地雷达无损探测试验  

Test on nondestructive detection of farmland solum structure in fluvo-aquic soil area using ground penetrating radar

作　　者：宋文[1,2] 张敏[1,2] 吴克宁[1,2] 李俐[3] 赵华甫[1,2] 李俊颖 Song Wen;Zhang Min;Wu Kening;Li Li;Zhao Huafu;Li Junying(School of Land Science and Technology,China University of Geosciences,Beijing 100083,China;Key Laboratory of Land Consolidation and Rehabilitation,Ministry of Land and Resources,Beijing 100035,China;College of Information and Electrical Engineering,China Agricultural University,Beijing 100083,China)

机构地区：[1]中国地质大学(北京)土地科学技术学院,北京100083 [2]国土资源部土地整治重点实验室,北京100035 [3]中国农业大学信息与电气工程学院,北京100083

出　　处：《农业工程学报》2018年第16期129-138,共10页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家科技支撑计划(2015BAD06B01)

摘　　要：为探究探地雷达对自然土壤土体构型进行快速无损探测的可行性,该文首先利用基于时域有限差分法的Gpr Max2D软件模拟4种具有不同介电特性差异的土壤层次的土体模型,识别雷达电磁波在具有不同土壤介电特性差异的土壤层次中传播时反射波振幅和相位的客观变化规律;然后于2016年在位于黄淮海平原潮土区的河北省曲周县选择夹黏型和底漏型2种土壤层次较明显的农田土体构型进行GPR探测试验,并挖掘土壤剖面,通过雷达图像处理软件和MATLAB编程处理雷达图像并提取波形数据,根据模拟获取的规律进行土壤层次识别,对比探测层厚与实际剖面层厚。研究结果显示,雷达电磁波在不同介质分界面处发生反射,两侧介电特性差异越大,反射波振幅越大;上层介质介电常数小于下层会发生正反射,反之发生负反射;实测波形比模拟波形杂乱;通过电磁波振幅和相位变化识别层次界面清晰的夹黏型土体构型中较厚层次的厚度的相对误差(<9%)要小于识别层次界面不清晰的底漏型土体构型各层厚度的相对误差(>9%);可识别的层次界面反射系数均大于0.02,两侧土壤具有较大介电特性差异;通过客观判读依据可以判别农田潮土的层次结构,但层次界面的整齐清晰程度、界面两侧介电特性差异程度和相邻层次的厚度大小影响着探地雷达探测效果。该文可以为相关研究提供参考,为实现土体构型这一重要耕地质量指标的快速监测提供借鉴。Solum structure is an important index to evaluate the cultivated land quality.How to obtain the solum structure information quickly and accurately has been the hot spot in the fields of soil,land,water conservancy,agriculture,and so on.In order to explore the feasibility of rapid and nondestructive detection of solum structure in natural soil by ground penetrating radar(GPR),this paper first used GprMax2D software based on finite difference time domain(FDTD)to simulate 4 soil models including 3 soil layers with different dielectric characteristics,and recognized the objective change rules of amplitude and phase of the radar electromagnetic wave in those soil layers with different dielectric characteristics.Then,2 kinds of soil profile patterns i.e.clay interlayer type and sand bottom type with obvious soil layers in Quzhou County of Hebei Province,located in the alluvial soil area of North China Plain,were selected for GPR detection experiment in 2016,and soil profiles were excavated.The clay interlayer type solum structure indicated that a thin clay layer was in the soil mass,and the sand bottom type solum structure indicated that there was a sand layer at the bottom of soil mass with 1 m depth.Radar images were processed through radar image processing software and MATLAB programming to extract waveform data.According to the objective rules obtained by simulation,soil layer identification was carried out,and the detected thickness and measured thickness of every layer were compared.The results showed that the reflection of radar electromagnetic wave occurred at the interface of different media,and the greater the difference of dielectric properties between 2 sides,the greater the amplitude of reflected wave.If the dielectric constant of the upper layer was smaller than that of the lower layer,positive reflection would occur;otherwise negative reflection would occur.The measured waveform was more chaotic than the simulated waveform.The relative error(<9%)for identifying the thickness of the thicker layers of the

关 键 词：雷达 土壤 模型 土体构型 耕地质量 正演模拟 黄淮海平原 农田潮土 

分 类 号：S152[农业科学—土壤学]