基岩面埋深综合物探精细探测应用研究

Application of Comprehensive Geophysical Exploration in Fine Detection of Buried Depth of Bedrock Face

为提高物探探测基岩面埋深的精度,研究了不同物探方法探测基岩面埋深分辨率的差别。结合工程实例,采用地震波折射法、瑞雷面波法及高密度电法进行基岩面埋深探测,并通过钻探结果对比分析得出:地震波折射法探测基岩界面较直观,适合探测覆盖层厚度(基岩面埋深)较浅的场地,当探测区域基岩界面起伏较平缓时,探测精度相对较高;瑞雷面波法可探测出地下一定范围内各种地层介质的波速变化情况,当探测区域表层较松散且具有一定厚度时,探测精度相对较高;高密度电法可探测出地下一定范围内各种介质的电阻率变化情况,需辅以个别参数孔资料进行深度转换系数的校正,便能准确绘制基岩界面埋深及起伏变化情况。

To improve the accuracy of geophysical detection of the buried depth of bedrock,this paper studies the difference in the resolution of various geophysical exploration methods.Combined with engineering cases,the seismic refraction method,Rayleigh wave technique,and high-density resistivity method were used to detect the buried depth of the bedrock surface.The comparison of drilling results shows that:the seismic refraction method is straightforward and suitable for detecting the site with shallow layer(bedrock surface depth),and the detection accuracy is relatively high when the bedrock interface in the detection area fluctuates gently;the Rayleigh wave technique can detect the change of wave velocity of various stratigraphic media within a certain range,and when the surface layer of the detection area is loose and has a certain thickness,the detection accuracy is relatively high;the high-density resistivity method can detect the change in the resistivity of various media within a certain range,and when supplemented with information from individual parameter holes for the depth conversion coefficient correction,it is possible to accurately map changes in buried depth and fluctuation at the bedrock interface.