探地雷达在地下考古遗存探测中的实验与应用

Experiments and Applications of Ground Penetrating Radar in the Investigation of Subsurface Archaeological Interest

近年来,探地雷达被越来越多地应用于考古探查中。由于反演多解性问题的存在,雷达图像上的异常既可能是考古目标引起的,也可能是由于地下环境介质的不连续性引起的,所以探究不同类型的考古遗存在探地雷达图像上的典型异常响应,有助于准确识别雷达图像上的"真"异常,剔除一些"假"异常。首先,本文基于西北干旱-半干旱区文物埋藏环境,在河北省怀来县遥感综合试验站试验区设计实施了地下目标体探地雷达探测实验,分析了不同材质的小尺度目标体及夯土结构在探地雷达图像上的响应特征;然后,进一步将探地雷达应用于悬泉置遗址地下城墙基址的探测,对城墙在雷达图像上的响应特征进行了分析。实践表明,探地雷达技术在埋藏浅、小尺度、物性差异不大的考古探查中具有很好的效果,得到并解释了点状、线状、面状等不同考古目标体在探地雷达图像上的响应规律。

Ground Penetrating Radar（GPR） has been more and more widely used in archaeological investigations, because it can be a non-destructive, cost-effective way to locate buried structures in archaeological studies. Compared with the conventional geophysical tools used in the shallow explorations, the electromagnetic method, ground-penetrating radar（GPR）, is more economical and is capable to produce large amounts of continuous, high resolution subsurface data. GPR canextend the exploration range of remote sensing（RS） to subsurface. However, because of the non-uniqueness of inversion, an anomaly could be raised by the archaeological interest or the inhomogeneity of underground matrixes, therefore studying the typical anomalies of diferent archaeological targets on GPR images is helpful to distinguish the＂true＂anamolies from the＂fake＂anamolies. Furthemore, some experiences and references could be provided. The following experiments have been carried out： firstly, in order to analysize how the small targets of different materials and rammed earth will raise anomalies on the GPR maps, GPR was emploied to detect five pre-buried targets that are equivalent to the archaeological interest and a beacon tower in a integrated experiment station of remote sensing. The first experiment of GPR prospection was designed to simulate the buried-enviorment of the archaeological structure in the northwest region of China whose climate is predominantly arid. Secondly, the authors applied GPR in detecting the residual city walls of Xuanquanzhi ruins, then analysized the response features of the walls, and found that the detecting results well fitted the excavation. The engineering practice indicates that the ground penetrating radar technology is successful and effective in invetigating the archaeological remains which are of small scale, buried shallowly and very analogical with the matrixes in electromagnetic nature. The response models of different archaeological targets, which are respectively considered as the point, line and surface shape, have been proposed and explained according to the principle of rectilinear propagation of electromagnetic wave.