摘要
微动勘探技术具有较强的空间适应能力和抗机械干扰能力,在复杂城市环境的地质勘探中被广泛应用。微动特征曲线的正演模拟均基于水平层状介质模型,而实际地层为典型非均匀地质模型,导致特征曲线拟合度不理想,有必要基于非均匀介质条件进行正演研究。水平层状介质假设的地质模型无法满足微动特征曲线的高精度正演要求,需基于非均匀模型进行正演。本文提出的动态优选法微动特征曲线正演技术,在等效水平层状介质理论特征曲线的基础上,计算随频率变化的孔径范围和优选系数,可实现非均匀介质的高精度特征曲线正演。以谱比曲线为例,采用动态优选法微动特征曲线正演技术能够更好地反演非均匀介质的横波分布,具有更高的横向分辨率和勘探精度。
The microtremor exploration technique has been widely used in the geological exploration of a complex urban environment due to its strong spatial adaptability and anti-mechanical interference ability.The forward modeling of microtremor characteristic curves is all based on a horizontally layered medium model, while actual strata are typical inhomogeneous geological models.The inconsistency leads to the unsatisfactory fitting degree of characteristic curves.Therefore, it is necessary to conduct forward modeling research based on the condition of inhomogeneous media.Since the geological model based on the assumption of horizontally layered media cannot meet the requirements for high-precision forward modeling of microtremor characteristic curves, forward modeling needs to be conducted using an inhomogeneous model.Based on the dynamic optimization method, this study proposed the forward modeling technique of microtremor characteristic curves to realize the forward modeling of high-precision characteristic curves of inhomogeneous media.In this technique, the aperture range and the optimization coefficients varying with frequency were calculated based on the theoretical characteristic curves of equivalent horizontally layered media.Taking spectral ratio curves as an example, the forward modeling technique of microtremor characteristic curves using the dynamic optimization method can obtain the shear wave distribution of inhomogeneous media through inversion, achieving higher lateral resolution and exploration precision.
作者
刘铁华
刘铁
张邦
卞友艳
张占荣
化希瑞
LIU Tie-Hua;LIU Tie;ZHANG Bang;BIAN You-Yan;ZHANG Zhan-Rong;HUA Xi-Rui(China Railway Siyuan Survey and Design Group Co.,Ltd.,Wuhan 430063,China)
出处
《物探与化探》
CAS
北大核心
2022年第5期1276-1282,共7页
Geophysical and Geochemical Exploration
基金
湖北省重点研发计划项目“城市地下空间精细化探测与感知关键技术及装备”(2021BAA050)
国家重点研发计划项目“城市地下空间精细探测技术与开发利用研究示范”课题一“城市地下空间开发地下全要素信息精准探测技术与装备”(2019YFC0605101)。
关键词
复杂城市环境
频率域特征曲线
非均匀介质
微动技术
动态优选法
complex urban environment
frequency-domain characteristic curve
inhomogeneous media
microtremor technique
dynamic optimization method
