起伏地形多道面波分析方法

Multi channel surface wave analysis method for undulating terrain

传统多道面波分析方法不适用于起伏地形条件,限制了其的应用场景.首先,基于聚束分析原理,提出了一种适用于地表起伏、地层界面水平的地质模型的多道面波频散曲线正演方法.数值分析结果表明,相对基于水平地形假设的传统频散曲线正演方法,本文方法正演的频散曲线与模拟地震记录提取的频散曲线吻合度更高.其次,提出以地层横波速度和地层界面高程为反演参数的反演策略,实现起伏地形多道面波频散曲线反演.通过起伏地形下模拟地震记录反演结果可知,相比传统多道面波分析方法,利用本文建立的起伏地形多道面波分析方法获得的横波速度剖面与地质模型一致性更好,验证了方法的有效性.

The traditional multi-channel analysis of surface wave (MASW) method is not applicable to rugged terrain conditions, which limits the application scenarios of MASW. Firstly, based on the principle of beamforming analysis, a forward algorithm of multi-channel surface wave dispersion curves in media with rugged topography and horizontal stratigraphic interfaces is presented. The numerical analysis results indicate that, compared to the traditional dispersion curve forward algorithm based on the assumption of horizontal strata, the dispersion curve obtained by the forward algorithm of this paper is more consistent with the dispersion curve extracted from simulated seismic records. Secondly, an inversion strategy is proposed, which takes the velocity of shear waves and the elevation of the formation interface as inversion parameters to achieve the inversion of multi-channel surface wave dispersion curves under rugged terrain. The shear wave velocity profile obtained by the MASW method established in this paper is more consistent with the geological model than traditional MASW methods, which verifies the effectiveness of the method.