Application of ground penetrating radar in mapping and monitoring landfill sites

The internal structure and the integrity of the containment walls are aspects of landfill site management that need to be continuously monitored. Monitoring currently involves construction of boreholes and chemical analyses of surface samples which are time-consuming and expensive. The applicability of ground penetrating radar (GPR) as an aid to monitoring these processes has been investigated. GPR surveys have successfully resolved the shallow depth soil and geological structure, identified the structure and history of the waste input, defined the water table in three dimensions and identified leachout breakout points in the impermeable lining of the landfill edges. Integration of the results of GPR surveys with data from surface surveys and boreholes could provide landfill operators, environmental agencies and commercial companies with a cost-effective monitoring methodology and a mechanism for enhancing contaminant migration modelling.     

探地雷达在铁路隧道检测中的应用

基于铁路隧道衬砌质量检测项目,结合探地雷达检测过程中发现的一些问题,列举了不同地质情况下,隧道衬砌检测、衬砌背后回填密实程度检测、钢筋检测、钢架检测的典型雷达图像特征.     

Buried pipe detection by ground penetrating radar using the discrete wavelet transform

Ground penetrating radar (GPR) is widely used for non-invasive examination of man-made structures, especially to determine the depth of pipes buried underground. Unfortunately, shallower objects may obscure GPR raw data that is reflected from deeper ones. This study introduces a signal processing technique, called the discrete wavelet transform (DWT), to filter and enhance the GPR raw data in order to obtain higher quality profile images. Laboratory experiments were conducted and the locations of buried pipes under different conditions were analyzed. The buried pipes were made of plastic and metal, and both single and two parallel horizontal pipes are discussed. The experimental results indicate that the DWT profiles can provide more information than the traditional GPR profile. The images of the diameter and position of pipes, even two pipes of different materials and in horizontal alignment, can be enhanced by using the DWT profile.     

堤防动物洞穴的探地雷达探测研究

通过探地雷达对淮沭河大堤獾洞隐患的探测,分析了獾洞的结构特征,给出了獾洞的典型雷达图像特征,推断了测区内獾洞穴道的位置、深度和走向,为堤防獾洞隐患治理提供了资料。探测结果表明,探地雷达设备轻便,对场地要求低,易于在任意方向加密探测,对浅层地下洞穴的探测非常有效。     

Collapse hazard assessment in evaporitic materials from ground penetrating radar: a case study

Evaporitic materials have been studied by means of ground penetrating radar (GPR) in order to evaluate the collapse hazard. The obtained 200 MHz GPR profiles show a low signal-noise ratio over the first 3 m depth, where well-defined and continuous reflectors can be observed. Between 3 and 4.5 m depth, the signal to noise ratio decreases due to attenuation of the electromagnetic (EM) waves. As a result, reflectors located deeper than 3 m become more discontinuous and poorly defined. GPR profiles show trails of continuous and subhorizontal reflectors, with a slightly undulated and irregular geometry. Although some of these reflectors laterally vanish or seem to disappear, sudden interruptions or hyperbolic reflections that could be originated by the occurrence of cavities have not been detected. These reflectors have been interpreted as corresponding to several evaporitic layers (gypsum) that constitute the main lithology in the area. Clear interruptions of reflectors have only been observed in some GPR profiles, and they could be attributed to small (1–2 m long) subvertical faults, with only a few centimetres offset. These faults may be generated by the accommodation of the evaporitic layers to local collapses affecting deeper materials.     

瞬时属性估计器在探地雷达数据处理中的应用

为了提高浅层埋藏目标识别的瞬时物理属性的精度,根据极平坦频率特性有限脉冲相应滤波器的思想,首次提出用它作为微分器和延时器组成解析信号瞬时属性估计器（FIFM）,对探地雷达信号的瞬时属性进行提取。结果表明,瞬时属性剖面的分辨率得到了明显的提高;采用瞬时属性估计器进行探地雷达信号瞬时参数的研究是一种非常有效的方法,可用于公路、桥梁、隧道等结构物的无损检测数据分析。     

探地雷达技术在煤矿采空区探测中的应用

不明采空区对煤矿的安全生产构成潜在危害,而人工地震勘探对埋深较浅的采空区存在盲区。采用RAMAC/GPR探地雷达仪配备的超强地面耦合天线(RTA50MHz)探测采空区。由于煤层及采空区相对雷达探测的有效范围较深,综合考虑探地雷达的分辨率与探测深度的关系,选用合适的雷达参数和探测模式进行数据采集,并采用了VC++开发了三维系统进行了补充解释,实现了探测目标体的准确定位,取得较好的探测效果。     

Experimental study on soil pollution analysis around tailings using ground penetrating radar

Pollution caused by tailings has become a serious environmental problem in China. An attempt was made to establish the ground penetrating radar （GPR） as a quick and non-destructive method for soil pollution analysis. Some physical models were established of contaminated soils from the tailing area. A series of indoor GPR experiments were conducted with 1 GHz antenna. The interface of contaminated area and uncontaminated area is characterized as a saltation zone in the radar image. The results of experiments show a clear correlation between the GPR data and the pollution intensity of soil. Based on all experimental data, the relation of velocity of electromagnetic wave propagation and pollution intensity was induced by using artificial neural network （ANN）. The results obtained indicate that GPR can provide high-resolution estimates of soil pollution variations around tailings as a function of depth as well as space and time.     

曙光雷达数据处理软件系统

针对岩土工程探测对象的隐蔽性与复杂性,开发了曙光雷达数据处理软件系统,实现了不同类型雷达数据的共享数据处理、分形处理、偏移、联合反演、小波变换等功能;现场验证及试用结果表明,该软件系统可以改善地下目的物探测的分辨率和真实度,可为岩土工程施工提供较准确的地下障碍物资料。     

探地雷达在公路隧道衬砌检测中的应用

分析总结了隧道衬砌存在的常见问题及缺陷在雷达图像中的显现特征,并将探测结果与实际地质概况进行对比分析。结果表明,探地雷达能够对隧道衬砌实施连续扫描,获得形象直观的探测图像,利用探地雷达检测公路隧道衬砌,具有无损、快速、广泛、精确等优点。     

Pulse EKKO Pro探地雷达勘查地质灾害的原理和方法

探地雷达法是一种以电磁波为基础的地球物理勘探方法。本文以北京昌平白羊沟崩塌勘查为例,利用探地雷达查明了危岩体顶部裂隙灾害分布范围及发育状况,为危岩体的稳定性评价提供了科学依据。     

X3M探地雷达在城市地下管线探查中的应用

论文介绍了X3M探地雷达在地下管线探查的应用,对一些典型的探测图像进行了说明,并对其工作方法提出了一些建议。     

断层特征参数地质雷达探测与识别的应用研究

在地下空间中,用地质雷达方法沿水平方向探测可以确定断层的位置及走向,沿垂直方向探测可以测定断层的倾向、倾角和落差,但不能用于查明断层面内充填物的详细情况。因此,采用地质雷达方法对断层部分特征参数的准确判定,对地下工程的开挖与维护具有一定的工程地质意义。     

探地雷达在南京地铁隧道工程检测中的应用

溶洞是地铁隧道工程的重要检测内容之一,探地雷达波在溶洞中传播的信号特征与围岩存在明显的差别,雷达反射波组的振幅、波长和频率会随着介质的电性变化而改变,正确识别溶洞的雷达波组特征是判别溶洞存在及其性质的关键所在。以南京地铁三号线滨江路站-五塘村站之间地铁隧道下方岩体内隐含溶洞探测为例,着重讨论了溶洞在探地雷达检测剖面上的波形显示特征,结合钻孔验证,说明探地雷达技术在城市地铁隧道工程溶洞探测中是有效的和实用的。     

一种用于混凝土结构探测的探地雷达天线阵列的设计

基于脉冲体制探地雷达天线原理,针对混凝土结构探测的需求,以变形领结天线为基础,设计了一种双极化、多天线的探地雷达天线阵列,该天线阵列具有0.75~2.25 GHz 的频带宽度,且方向性良好。该天线阵列不仅可以提高雷达系统的探测深度,也提高了雷达的探测效率。设计的天线阵列已成功应用于成像探地雷达项目中,对工程质量检测具有重要意义,为探地雷达三维成像设备的进一步开发提供了强有力的技术支撑。     

探地雷达应用于城市固体废弃物填埋场的构想

介绍了探地雷达技术的基本工作原理及其在某些领域的应用效果,提出了应用探地雷达技术进行城市固体废弃物填埋场选址、渗漏检测以及封场后覆盖层厚度测定等研究的构想,并探讨了探地雷达技术的可行性和技术优势。在总结相关文献的基础上,结合现场调查认为,应用探地雷达技术进行填埋场选址、渗漏检测以及封场后覆盖层厚度测定等研究工作是行之有效的一种新方法。     

基于小波域KL变换的探地雷达信号处理

探地雷达目标回波信号通常会受到串扰(或直达波)、随机噪声等的干扰,致使目标信号难以分辨。利用小波分析的时频局部化特性和多道探地雷达记录中直达波、目标回波信号以及随机噪声等的不同相关性,对探地雷达记录进行小波分解,得到多频段的小波剖面,再对不同频段的小波剖面做KL变换,实现了串扰抑制。通过实验数据和现场实测数据验证了该方法的有效性。     

一种低频探地雷达天线屏蔽装置实验研究

低频探地雷达系统多配置无屏蔽天线,抗干扰能力差.针对中心频率15 MHz的低频探地雷达天线,以铁丝网作为屏蔽材料,设计制作了3种尺寸(长×宽×高分别为:12 m×12 m×5 m、11 m×11 m×5m、9.6 m×9.6 m×5 m)的屏蔽装置,对接收天线和发射天线分别进行了屏蔽干扰实验研究.结果表明:网孔为1 cm×1 cm,丝径t为0.15 cm铁丝网是制作屏蔽装置的有效材料;对接收天线单独进行电磁屏蔽时,三种尺寸的屏蔽装置均显示出较好的屏蔽效果,其中最佳尺寸为11 m×11 m×5 m;对发射天线单独进行电磁屏蔽时,只有11m×11m×5m尺寸的屏蔽装置最有效,另外两种尺寸的装置屏蔽效果相对较差;相对而言,给接收天线单独增加屏蔽装置要比单独给发射天线增加屏蔽装置好.实验结果为下一步研发实用化的低频探地雷达屏蔽装置打下了良好基础.     

水泥混凝土路面脱空的探地雷达图像特征分析

脱空是水泥混凝土路面的常见病害,也是行车安全的主要隐患。探地雷达法通过观测分析高频电磁波反射信号特征来研究探测目标体的性质与规模,可以快速、有效地确定路面脱空的位置与充填情况。GprMax2D模拟结果、雷达实测资料和开挖验证情况的综合分析成果表明,充泥和充气空洞的雷达图像十分相似,特征明显,在空洞正上方都会出现一组非常明显的强反射信号,同相轴呈弧型,由于介电常数的明显差异,使得空洞充泥时反射波与直达波相位相反,而充气时反射波与直达波相位相同;不密实区域同相轴错断,显示出多条不规则弧形曲线。     

探地雷达探测地下管线机理研究及实例分析

探地雷达是一种适应快速、准确探测地下障碍物而迅速发展的新型电磁仪器。探讨了探地雷达探测地下管线的机理,得出了走时曲线方程,并通过对探测实例详细地分析亦探讨了复杂条件下探地雷达资料采集和图像解释的方法,介绍了一维滤波、偏移回归、时深转换等数据处理方法和经验,验证了该方法的可行性,表明该技术具有良好地应用前景。