李宝春，孙少槐，李国平. SPAC法在第四系地层分层中的应用[J].河南理工大学学报(自然科学版), doi: 10.16186/j.cnki.1673-9787.2023120033.

LI B C，SUN S H，LI G P. Application of SPAC method in dividing strata of the Quaternary strata [J]. Journal of Henan Polytechnic University( Natural Science), doi:10.16186/j.cnki.1673- 9787. 2023120033.

SPAC法在第四系地层分层中的应用(网络首发)

李宝春 ^1，2，3，孙少槐 ^1，2，李国平 ^1，2

（1.内蒙古工业大学 资源与环境工程学院，内蒙古自治区 呼和浩特 010051；2.内蒙古工业大学 地质技术与岩土工程内蒙古自治区工程研究中心，内蒙古自治区 呼和浩特 010051；3.中国地质大学（北京）地球物理与信息技术学院，北京 100083）

摘要:空间自相关法（the spatial autocorrelation method，SPAC法）是从环境噪声中提取相速度最有效的方法之一，使用SPAC法计算S波速度结构对研究地下速度结构具有重要意义。 目的 为验证SPAC法在第四系地层分层中的可靠性， 方法 使用多重观测阵列采集频率 2~40 Hz的微动信号，计算A，B，C台站组与中心台站的空间自相关系数，并使用零阶贝塞尔函数拟合空间自相关系数，同时提取Rayleigh面波相速度-频率关系，得到相速度频散曲线。与含低速软夹层模型、含高速硬夹层模型和速度递增模型相比，分歧型遗传算法反演频散曲线具有不依赖初始模型的优点。 结果 以华北克拉通北缘某地实测资料为例，使用 SPAC 法、瞬态面波法、波速测井法反演地层S波速度结构，根据钻孔资料可知，地下 6.7~9.0 m 深处为全风化片麻岩，表现出低至305 m/s的S波速度，9.0 m以下为强风化斜长片麻岩，表现为430~540 m/s的高S波速度。 结论 综合SPAC法、瞬态面波法、波速测井法和钻孔资料可知，SPAC法不仅地层分层准确性高，而且波速值大小与其他方法测试结果基本一致，验证了SPAC法的可靠性。

关键词: SPAC法；微动信号；S波速度结构；频散曲线；Rayleigh面波

中图分类号：P315　　

doi: 10.16186/j.cnki.1673-9787. 2023120033

基金项目: 国家自然科学基金资助项目（42167023）；内蒙古自然科学基金资助项目（2021LHBS04002，2023QN04007）

收稿日期：2023-12-13

修回日期：2024-04-08

网络首发日期：2024-05-21

Application of SPAC method in dividing strata of the Quaternary strata (Online)

LI Baochun^1，2，3，SUN Shaohuai^1，2，LI Guoping^1，2

（1.School of Resources and Environmental Engineering，Inner Mongolia University of Technology，Hohhot 010051，Inner Mongolia，China；2.Inner Mongolia Engineering Research Center of Geological Technology and Geotechnical Engineering，Inner Mongolia University of Technology，Hohhot 010051，Inner Mongolia，China；3.School of Geophysics and Information Technology，China University of Geosciences，Beijing 100083，China）

Abstract: The SPAC method is the most effective method to extract phase velocity from environmental noise.The calculation of S-wave velocity structure by the SPAC method has important scientific significance for studying velocity structure. Objectives To verify the reliability of the SPAC method in dividing strata of the Quaternary strata, Methods this study used a multi-observation array to collect microtremor signals within 2 to 40 Hz.It calculated the spatial autocorrelation coefficients between Stations A,B,and C groups and the central station.Furthermore,zero-order Bessel functions were used to fit the spatial autocorrelation coefficients.It extracted the phase velocity-frequency relationship from the Rayleigh surface wave to obtain the phase velocity dispersion curve.Contrasting the Forking Genetic Algorithm fGA,the Low-Velocity Soft Layer Model,the High-Velocity Hard Layer Model,and the Velocity-Increasing Model,the Forking Genetic Algorithm fGA exhibits the advantage of inverting the dispersion curve without relying on an initial model. Results We used the SPAC,transient Rayleigh surface wave,and wave velocity logging methods to invert the S-wave velocity structure in the northern margin of the North China Craton.It is found that within the depth of 6.7 to 9.0 m,the fully weathered gneiss exhibits S-wave velocities as low as 305 m/s,whereas the strongly weathered plagioclase gneiss shows higher S-wave velocities ranging from 430 to 540 m/s below 9.0 m. Conclusions Based on the SPAC,transient Rayleigh surface wave,wave velocity logging methods and drilling data,it can be seen that the accuracy of stratigraphic stratification and S-wave velocity value of the SPAC method are consistent with other results,which verifies the reliability of the SPAC method.

Key words：SPAC method;microtremor signal;S-wave velocity structure;dispersion curve; Rayleigh surface wave

CLC: P315