直流高密度电法在浅海工程勘察中的应用

THE APPLICATION OF DC RESISTIVITY TO SHALLOW MARINE ENGINEERING EXPLORATION

用于海域工程勘察的物探方法相对较少,地震反射波法是水域工程物探的首选方法,但当遇到海底沉积层中含浅层气时,声波信号受屏蔽导致地震探测失效;因此尝试采用直流高密度电法探测浅海工程海底沉积层厚度和基岩面起伏情况。结合电阻率测井资料建立模型并进行正反演计算分析,并通过广东汕头市苏埃通道工程实例证实直流高密度电法可以获得较为理想的探测效果。在局部地震反射波法有效的区段进行两种物探方法的综合解释,可以提高解释的可靠性及解释的精度。

Fewer geophysical methods can be utilized in marine project exploration than in the land. Seismic reflection is the preferred geophysical choice. When the submarine sediments are contaminated by shallow gas, the shielding effect of acoustic signal leads to the failure of seismic detection. In this paper, the high density DC resistivity method was adopted to investigate the submarine sedimentary strata as well as the underlying bedrock. The forward and inverse model was built and calculated based on the resistivity borehole log- ging data, a shallow onshore engineering with this method was conducted and the results show satisfactory results in the submarine engi- neering exploration. In some parts of the area where seismic reflection works effectively, the authors explained the geology with compre- hensive methods, which could ensure the reliability and improve the accuracy of the interpretation.