堤岸隐患探测中的地球物理方法及应用

Geophysical Methods and Application in the Detection of Potential Safety Hazards in Embankment

随着时间的流逝与河水的冲蚀,黄河故道堤岸工程在长期运行中会出现洞穴、裂缝、松散体、脱空区等不良地质现象,将会影响堤岸工程的安全运行,因此,对堤岸隐患进行定期、定向探测十分重要。针对这些不良地质现象与周围环境之间的地球物理参数的差异性,本文采用探地雷达法、高密度电阻率法、瞬态瑞雷面波法等地球物理方法进行探测。首先,根据探测目标相对介电常数的大小及波阻抗界面的强弱的差异性,采用探地雷达法对河堤两岸进行普探,由此确定堤岸隐患的存在及位置;然后,以雷达资料解译结果为基础,采用高密度电阻率法进行详查,根据电阻率数值对目标进行深入判断;最后,引入纵波速度这一物性参数,采用瑞雷面波法对上述位置进行复测,验证探测深度并推断是否存在渗漏水异常。根据探测目标地球物理性质的不同,逐级、逐步对目标进行探测和识别,最终确定黄河故道堤岸隐患的存在、类型、分布、特征及规律。实践证明,以地球物理特征差异性为基础,采用“多类型方案设计”对堤岸地质隐患进行探测,并辅以“高密度测线布设”,在黄河故道堤岸隐患探测中具有快速、精细、准确、无损探测的特点,取得了良好的应用效果,值得在实践中进行推广和应用。

With the elapsing of time and erosion of river water,adverse geological phenomena such as caves,cracks,loose bodies,and evacuated areas will appear in the long-term operation of embankment project of the oldcourse of the Yellow River,and the safety of the embankment project will be affected.Thus,it is very important to carry out regular and specific detection of hidden dangers of the embankment.In view of the differences in geophysical parameters between these unfavorable geological phenomena and the surrounding environment,ground penetrating radar(GPR)method,high density resistivity method,and transient Rayleigh wave are applied in this paper for detection.Firstly,according to the difference of detection target in relative dielectric constant and strength of wave impedance interface,the GPR method is used to conduct general exploration on both sides of the embankment,so that the existence and location of the hidden danger of the embankment is determined.Secondly,based on the interpretation results of radar data,the high density resistivity method is used for detailed investigation,and the target is deeply examined according to the resistivity value.Finally,the Rayleigh surface wave method is used to re-measure the above-mentioned positions to verify the detection depth and infer whether there is an abnormal leakage.According to the detected target’s difference in geophysical properties,the target can be detected and identified step by step,and finally the existence,type,distribution,features and laws of safety hazards can be determined.Based on the difference in geophysical characteristics,the geological hidden dangers of embankment are detected by“multi-type scheme design”and supplemented by the“high density survey line layout”.Practice has proved that the comprehensive geophysical method is a fast,precise,accurate,and non-destructive method in detecting hidden hazards in the embankment of the old Yellow River,which has a good application effect and is worthy of being applied and popularized in practice.