多道面波勘探排列参数的影响研究——以双层凸起地质模型为例

Study on the Influence of Arrangement Parameter of Multi-channel Surface Wave Exploration in Complex Terrain——Taking Double-layer Raised Geologic Model as an Example

多道瞬态面波法(MASW)获取地层剪切波速度方便快捷,目前已广泛应用在工程勘探领域,特别是在复杂地形条件下的应用逐步增多;针对复杂地形条件下,数据采集至关重要,其中排列参数选择是一个重要因素,以双层凸起地质模型为例,通过对不同偏移距和道间距的排列系统进行高精度有限差分数值模拟研究;对比分析数据频率谱,讨论不同偏移距与道间距对瑞雷波频散分辨率特征的影响,为现场数据采集提供理论指导;结果表明:在一定数量的通道数和横向分辨率允许的情况下,大道间距是优选,偏移距尽量大以避免近场效应。

Multi--channel transient surface wave method （MASW） is convenient and rapid in acquiring strata shear wave velocity, and has been widely used in engineering exploration, especially in complex terrain. In the case of complex terrain, data acquisition is very important. The selection of arrangement parameter is an important factor. Taking double--layer raised geologic model as an example, this paper studied the high precision finite difference numerical value through the arrangement system of different offset and track pitch. The influence of different offset and track pitch on the resolution characteristics of Rayleigh wave dispersion rate is discussed by comparing the data frequency spectrum, which provides theoretical guidance for field data acquisition. The results show that the aisle spacing is preferable when a certain number of channels and lateral resolution are allowed; the offset should be as large as possible to avoid the near--field effect.