摘要
随着通车里程不断地增加,交通流量不断地增大,超重车辆绝对数量也不断地增加,加之施工不合理,使得大部分高速公路普遍发生了早期病害。其中对路面使用性能和使用寿命影响最大的是结构性破坏、水破坏和严重车辙,这严重影响了行车安全,并且进一步导致维修成本的增加。而高速公路浅层含水量可从一定程度上反映高速公路浅层质量状况。
常用的无损地下含水量检测技术主要有红外反射法和时域反射法两种,但是它们存在检测速度慢、且不能连续大规模的对高速公路浅层含水量进行估计。而探地雷达具有快速测量,使用起来便捷,对所测物无损害无干扰,可重复测量,适合大面积测量等优点,近来广泛的用于高速公路基础设施检测。但是,GPR跟光学成像设备不同,它不能直接反映目标的特征。因此,使用GPR勘查高速公路路面浅层质量时,如何由获取的GPR数据估计高速公路路面浅层含水量成为问题的关键。
本文的主要工作是结合探地雷达技术、信号检测与估计及信号处理技术实现高速公路浅层含水量的自动估计。其主要技术手段和研究内容为:
1)高速公路浅层层界面检测及时延估计:主要利用探地雷达回波信号杂波抑制算法和阈值检波法实现探地雷达数据预处理和高速公路层界面检测和时延估计:
2)高速公路浅层介电常数反演和含水量估计:利用每层层界面反射信号的幅度,通过经验模型反演每层介电常数和通过Topp和Roth经验模型反演高速公路浅层含水量。
As the increase in traffic mileage and traffic flow, and the swelling in overloaded vehicles, and the improperness in construction, damages spread to most of highways in China. The most deadly factors that affect highway usability and working life are damages to highways' structures, destructions to water and the overloading of vehicles. This severely influences security of driving and leads to increase in maintenance cost. To solve these problems, it is important to understand the situation of the highway shallow-layer's quality. The water content of shallow-layer could reflect the situation to some extent.
Infrared reflectance method and time domain reflectance method are two widely used safe methods to detect water content. But, both of those two methods are slow, and they cannot be used to detect shallow-layer water content in a wide range. While, not only as a quick method, the ground penetrating radar (GPR) method is also easy to use and has no damage to subjects to be detected. GPR is a repeatable measuring method. Most importantly, it can be used to measure water content of a large area. This method is now prevailed in detecting fundamental facilities on the highway. But, being different from optical imaging, GPR cannot reflect characters of subjects directly. Thus, when GPR is used in analyzing highway shallow-layer's quality, how to get data to estimate water content in shallow-layer is the key issue.
The main work of this study is to detect water content of highway shallow-layer automatically by combining GPR, signal detecting and analyzing technology and signal processing technology. The main content of the study are:
1) Detection and delaying estimation of highway shallow-layer' layer interface: calculating GPR reflecting wave signal by using clutter suppression algorithm and threshold detector method to pre-process GPR data, detect highway layer interface and estimate delay.
2) Inversion of highway shallow layer's dielectric constant and estimation of water content: applying amplitudes of each layer interfaces' reflecting signals to calculate highway shallow layer's water content by using experiential model to invert each layer's dielectric constant and using Topp and Roth experiential model toinvert water content of highway shallow layer.
引文
[1]Basic fact sheet,UN demining data base[EB],http://www.un.org/Depts/dha/mct/facts.htm.
[2]Bureau of Political-Military Affairs.Hidden killers[EB].U.S.Department of State Publication 10575.1998,http://www.state.gov/global/arms/rpt/ 9809/demin/ demine/ toc.html.
[3]J D Nicoud.Mine clearance,not only a problem for the military any more[J],in Proc.of ISMCR,1996,6-10.
[4]B S G Janzen.Improving the technology for humanitarian demining[C].Proc,1996,IEE/EUREL Conf.on the Detection of Hidden Land Mines,Edinburgh,UK,1996,11-15.
[5]T Kaneko.Radar image processing for locating underground linear objects[J].IEICE Transaction(Japan),Oct.1991,74(10):3451-3459.
[6]E Fisher and G A Mcmechan.Examples for reverse-time migration of single-channel ground penetrating radar profiles[J].Geophysics(USA),Apr.1992,57(4):577-586.
[7]Lakshman W Galagedara.The GPR direct ground wave method for soil moisture content estimation:field experiments and modeling[D].University of Guelph,2003.
[8]D J Danieis.Surface-Penetrating Radar[J].Electronics & Communication Engineering Journal,1996,8:165-182.
[9]D J Daniels,D J Gunton and H E Scott.Introduction to Subsurface Radar[J].IEEE Proc.1988,35(4):278-320.
[10]范国新,陈平.探地雷达原理、设计思想及其实现[J].电波科学学报,1992,7(9):1-20
[11]刘传孝,蒋金泉,杨永杰.国外探地雷达技术的比较与分析[J].煤炭学报,2002,27(2):123-127.
[12]J D Young and R Caldecott.Underground pipe detector[P].U.S,Patent,:3967282,1976.
[13]A C Eberle and J D Young.Development and field testing of a new locator for buried plastic and metallic utility lines[J],in Transportation Research Record 631.National Academy of Science,1977.
[14]J J Daniels and R L Roberts.Ground Penetrating Radar for Geotechnical Application[J].Geophysical Characterization of Sites,American Society of Civil Engineers,ISSMFE TC #10Publication on Geophysics,special vol.3 ICSMFE,1994,New Delhi,India.
[15]J J Daniels.Locating caves,tunnels and mines:the leading edge of exploration[J].Soc.Expl.Geophy.Jan-Feb,1988.
[16]J J Daniels,R Roberts,M Vendl.Site studies of ground penetrating radar for monitoring petroleum product contaminants[J],in Trans.Syrup.On the Application of Geophysics to Engineering and Environmental Problems,Apr.26-29,1992.
[17]http://diwww.epfl.ch/lami/detec/mine101inks.html
[18]李太全.探地雷达天线系统的设计,实现与优化[D].武汉大学,2004.
[19]刘恒柏,朱安宁,张佳宝,等.不同水分条件下粗砂土剖面中目标物的GPR图象特征及其解译[J].土壤,2009,41(1):112-117
[20]朱安宁,吉丽青,张佳宝,等.基于探地雷达的土壤水分测定方法研究进展[J].中国生态农业学报,Sept.2009,17(5):1039-1044.
[21]刘恒.路用探地雷达在道路工程中的应用研究[D].大连理工大学,2002.
[22]黎春林.探地雷达检测路面含水量和压度的应用研究[D].郑州大学,2003.
[23]M Storme.Microwave characterization of wet soils[D].Tech.Rep.HuDEM F97-06-WG1,Universite Catholique de Louvain,April 1998.
[24]Y Wakita and Y Yamaguchi.Estimation of the soil permittivity and conductivity by a GPR antenna[C].GPR'96:International conference on Ground Penetrating Radar,Sep.30-Oct.31996,123-127.
[25]D J Daniels,D J Gunton and H E Scott.Introduction to Subsurface Radar[J].IEEE Proc.1998,35(4):278-320.
[26]Hollis C Chen.Theory of Electomagnetic Waves,A Coordinate-Free Approach[M].McGraw-Hill,New York,1983.
[27]J W Brooks.The Detection of Buried Non-Metal Anti-Personnel Land Mines[D].University of Alabama,Huntsville,2000.
[28]D.J.Daniels.Surface-Penetrating Radar[J].Electrenics & Communication Engineering Journal,1996,8:165-182
[29]李大心.探地雷达方法与应用[M].地质出版社,1994.
[30]http://diwww.epfl.ch/lami/detec/gprimages.html
[31]J W Brooks,L van Kempen & H Sahli.Primary Study in Adaptive Clutter Reduction and Buried Minelike Target Enhancement from GRP Data[J].in Proc.of SPIE,AeroSense 2000:Detect.and Rem.Techn.for Mines and Minelike Targets,2000,4038:1183-1192.
[32]D Carevic.Clutter Reduction and Target Detection in Ground Penetrating Radar Data Using Wavelets[J].in Proc.of SPIE Conference on Detect.and Rem.Techn.for Mines and Minelike Targets,1999,3710:973-976.
[33]R Wu,A Clement,J Li and E Larsson.Adaptive ground bounce removal[J].Electron.Letter, 2001,37: 1250-1252.
[34] K Gu, J Li, M Bradley and G Maksymonko. Adaptive ground bounce removal[J]. in Proc. SPIE-Int. Soc. Opt. Eng., 2001, 4742: 700-711.
[35] H Deng & H Ling. Clutter Reduction for Synthetic Aperture Radar Images Using Adaptive Wavelet Packet Transform[J]. in Proc. of IEEE Int. Antennas and Propagation Society Symposium, 1999, 3: 1780-1783.
[36] J L Salvati, C C Chen & J T Johnson.. Theoretical Study of a Surface Clutter Reduction Algorithm[J]. in Proc. of 1998 IEEE Interantional Geoscience and Remote Sensing, 1998, 3:1460-1462.
[37] H Brunzell. Clutter Reduction and Object Detection in Surface Penetrating Radar[J]. in IEEE Trans. Geoscience and Remote Sensing, 1999, 37(2): 875-878.
[38] H Brunzell. Detection and Classification of buried objectas Using Impulse Radar Measurements[J]. Technical report no. 2431, Chalmers University of Technology, Sweden,1998.
[39] H Brunzell. Pre-processing of Ground Penetrating Radar Data for Improved Detection Capability[J]. in IEEE Trans. Geoscience and Remote Sensing, 1998, 1478-1580.
[40] L V Kempen, H Sahli. Ground Penetrating Radar data processing: a selective survey of the state of the art literature [J]. Technical Report, Vrije Universiteit Brussel, Brussel, Belgium,1999, 1-35.
[41] L V Kempen, H Sahli, E Nyssen, and J Cornells. Signal processing and patterns recognition methods for radar mine detection and identification[C]. in Proc. 1998 IEEE/EUREL Conf. on the Detection of Hidden Land mines, Edinburgh, UK, 1998, 458: 81-85.
[42] M P Kolba, I I Jouny. Clutter suppression and feature extraction for landmine detection using ground penetrating radar[J]. Symposium on Antennas and Propagation Society, 2003, 2:203-206.
[43] M Fritze. Detection of buried landmines using ground penetrating radar[J]. in SPIE Proc,1995,2496: 100-108.
[44] R Ekstein. Anti-Personal Mine Detection-Signal Processing and Detection Principles[J].Technical Report, vrije Universiteit Brussel, Brussel, Belgium, 1997, 1-123.
[45] D L Donoho, I M Johnstone. Ideal spatial adaptation by wavelet shrinkage[J]. Biometriac,1994,81:425-455.
[46] D L Donoho, I M Johnstone. Threshold Selection for wavelet shrinkage of noisy data[C].Engineering in Medicine and Biology Society, 1994, Engineering Advances: New Opportunities for Biomedical Engineering.IEEE Proceedings of the 16~(th) Annual International Conference,1994,A25-A25.
[47]R R Coifman and M V Wickerhauser.Entropy-based algorithms for best basis selection[J].IEEE Trans.Inform.Theory,1992,38(2):713-719.
[48]H Krim,D Tucker,S G Mallat.On Denoising and Best Signal Representation[J].IEEE Trans.Inform.Theory,1999,5(7):2225-2238.
[49]Q Pan,L Zhang and G Z Dai.Two Denoising Methods by Wavelet Transform[J].IEEE Transacions on Signal Processing,1999,47(12):3401-3406.
[50]张蓓.路面结构层材料介电特性及其厚度反演分析的系统识别方法-路面雷达关键技术研究[D].重庆大学,2003.
[51]侯晓冬.利用探地雷达(GPR)进行土中水油盐含量的快速确定研究[D].中国海洋大学,2008.
[52]何亮,王旭东,杨放,等.探地雷达测定土壤含水量的研究进展[J].地球物理学进展,2007,22(5):1673-1679.