地面穿透雷达检测公路路基岩溶洞穴的应用研究

Application of Ground Penetrating Radar to Detect Karst Caves in Highway Subgrade

主要采用公路隧道中最常用的地质雷达法(GPR)进行,通过对其使用原理、优缺点、应用条件的分析,以湖南某隧道工程为例,采用有限差分方法对岩溶地质灾害进行数值模拟,结果表明,如果某地区存在较大的电解质差异性,最终能够通过各种手段得到较好的雷达探测效果。溶洞的探地雷达具有较强的反应,空洞、填充溶洞或者基岩的电常数具有较大差异,溶洞界面很可能将导致探地雷达出现弧形,并且造成比较强的反射。雷达同相轴的散乱、不连续等情况也经常出现再裂隙发育、岩体破碎等状况,同时其反射能量非常强,在评价岩体完整性的过程中需要综合上述指标进行操作。

This paper mainly adopts the most commonly used geological radar method(GPR)in highway tunnel.Through the analysis of its principle,advantages and disadvantages and application conditions,this paper takes a tunnel project in Hunan as an example and uses the finite difference method to simulate the karst geological disasters.The result shows that the difference of dielectric is larger.In the area,ground penetrating radar(GPR)is used to detect and select reasonable acquisition parameters and antennas.The ground penetrating radar(GPR)has a strong reaction to the karst cave,and there is a great difference in the dielectric constant of the bedrock and filling cavities or holes.The cave interface will cause the radar data of the GPR to appear in arc,and the reflection is stronger.The fracture of rock mass and the development of fracture will cause the scattering of the same phase axis of the radar,the discontinuity of the phase axis and the strong reflection energy,which can be used to evaluate the integrity of the rock mass.