可控源音频大地电磁和折射地震在隧道勘查中的应用:以沈白铁路杨树隧道为例

Application of Controllable Source Audio Frequency Mag-netotelluric and Refraction Earthquake in Tunnel Exploration:a Case Study of Yangshu Tunnel on Shen-Bai Railway

为查明沈白铁路杨树隧道浅层土石分界、深部断层、破碎软弱带及岩体完整性等不良地质情况,选择可控源音频大地电磁测深和浅层地震折射相结合的综合地球物理勘察方法。CSAMT数据处理采用一维反演、地震折射数据处理采用表层剥去法并进行纵波层析成像。在成果解释时采用二者相结合的方式,浅层地层划分重要参考地震折射的解释成果,深部构造、破碎带及软弱岩层划分参考CSAMT测深断面成果。勘察成果表明利用可控源音频大地电磁测深和浅层地震折射相结合的综合地球物理方法可对隧道的浅部地层和深部的不良地质体进行有效划分,并使解释的可靠性得到大大的提高,弥补了单一物探方法解释的缺陷,提高了解释精度,是一种行之有效的综合物探方法。

In order to find out the unfavorable geological condi-tions such as shallow earth rock boundary,deep fault,broken weak zone and rock mass integrity of Yangshu tunnel of Shen Bai rail-way,a comprehensive geophysical survey method combining con-trollable source audio magnetotelluric sounding and shallow seis-mic refraction is selected.CSAMT data processing adopts one-di-mensional inversion,seismic refraction data processing adopts sur-face stripping method,and P-wave tomography.The combination of the two is adopted in the result interpretation.The shallow stra-tum division mainly refers to the interpretation results of seismic refraction,and the deep structure,fracture zone and soft rock stra-tum division refer to the CSAMT sounding section results.The sur-vey results show that the comprehensive geophysical method com-bined with controllable source audio magnetotelluric sounding and shallow seismic refraction can effectively divide the shallow stra-tum and deep unfavorable terranes of the tunnel,greatly improve the reliability of interpretation,make up for the defects of single geophysical interpretation and improve the interpretation accuracy,It is an effective comprehensive geophysical method.