基于背景噪声的自相关与HVSR联合成像在广东惠州城市浅层结构探测中的应用

Research on the application of auto-correlation and HVSR joint imaging based on ambient noise in the detection of urban shallow structures in Huizhou

随着我国城市化进程快速推进,大中小城市呈现地下空间全面开发的态势。然而城市地下空间开发利用存在地下情况不明、结构不清的问题,这在很大程度上影响了地下空间的开发利用和城市战略布局规划。广东惠州是典型的东部中型城市,为了避免老城区建成后地下水土质量不清楚、地下空间资源量不明确、城市地下空间资源开发无科学数据支持等问题,特在研究区开展绿色无损的背景噪声成像研究,以查明惠州地区的第四系及断层的发育情况,为新区成功建成提供数据支持。笔者等以台间距10 m、测线总长度1 km的密集地震台阵为基础,利用两条测线共200台的背景噪声数据,使用噪声自相关与噪声HVSR两种方法分别对研究区两条线性测线分别进行计算,通过数据预处理,单台数据处理,多台数据整合,最后得到了两条测线的自相关剖面和HVSR剖面。研究显示,研究区第四系基岩顶面时间域范围为20~100 ms,深度域范围为5~20 m,浅层P波速度范围为400~500 m/s,这与收集到的钻孔等资料相一致。研究表明基于密集台阵的噪声自相关与HVSR联合成像方法是一种高效、绿色、低成本的方法,可用于调查第四系分界面(强波阻抗分界面)及浅层沉积物中的活动断层。

With the rapid advancement of my country’s urbanization process,large,medium and small cities are showing a situation of comprehensive development of underground space.However,the development and utilization of underground space in many cities has problems such as unclear underground conditions and unclear underground space resources,which have greatly affected the underground space.The development and utilization of the city and the strategic layout planning of the city.Huizhou Tonghu New District is a typical eastern mid-sized urban new district.In order to avoid problems such as unclear ground water and soil quality,unclear underground space resources,and no scientific data support for the development of urban underground space resources after the completion of the old city,We specially carry out green economy ambient noise imaging research in the study area to find out the Quaternary situation and fault development in the Tonghu New Area of Huizhou,and provide data support for the successful completion of the new area.This study is based on a dense seismic array with a interval of about 10m and a length of about 1km.Using the ambient noise data of a total of 200 stations in two survey lines,two methods of noise auto-correlation and noise HVSR were used to measure two linear surveys in the study area.The lines are calculated separately,and through data preprocessing,single data processing,and multiple data integration,the auto-correlation profile and HVSR profile of the two survey lines are finally obtained.This study shows that the time domain of the Quaternary top of the study area is 20~100 ms,the depth domain is 5~20 m,and the shallow P-wave velocity range is 400~500 m/s,which is similar to the collected boreholes.The information is consistent.This study also shows that the combined method of noise auto-correlation and noise HVSR with dense arrays is an efficient,green,and low-cost method that can be used to investigate the Quaternary interface(strong impedance interface)and shallow sediments active faults in.