摘要
在固有硬件条件和采集环境下,观测排列是决定微动探测效果的关键因素。为了研究排列参数对微动探测效果的影响,以北京城区某拟建地铁项目为例,通过对24道线性排列进行抽道,形成不同排列长度、道间距的新排列,然后分析排列长度、道间距等线性排列参数对微动能量谱、探测深度、分辨率等的影响规律。研究结果表明:能量谱主要受排列长度和道间距影响,其中,低频能量主要受排列长度影响,排列越长,低频能量越集中。高频能量主要受道间距影响,道间距越大,高频能量缺失越多。探测深度主要受排列长度和频散曲线提取方法影响,道间距对探测深度的影响较小。采用ESPAC(扩展的空间自相关法)方法提取频散曲线和增大排列长度均可以使能量谱能量更集中,且可以提取更低频率的频散点,进而获得更精确的速度和更大深度的地层信息;排列长度越大,探测深度越大,但随着排列长度的增大,探测深度的增长速度趋缓。随着排列长度和道间距增大,反演横波速度剖面的分辨率逐渐降低,视横波速度和面波相速度剖面的分辨率也逐渐降低;另外,反演横波速度、视横波速度和面波相速度剖面的分辨率依次降低。因此,在利用微动勘探方法进行地质结构探测时,须根据探测目标的规模、埋深及场地条件,选取适宜的排列参数,以获得更精细的探测效果。
Under inherent hardware conditions and acquisition environments,the observation array is the key factor to determining the detection result.To study the influence of observation array parameters on the results of microtremor exploration,a planned subway project in the urban area of Beijing was used as an example.A new array with different array lengths and trace intervals was formed by extracting traces from 24 linear arrays.The influence of linear array parameters such as array length and trace interval on the microtremor energy spectrum,detection depth,resolution,etc.was analyzed.The research results indicate that the energy spectrum influenced mainly by array length and trace interval,among which the low-frequency energy is influenced mainly by array length,the longer the array length is,the more focused the low-frequency energy is.The high-frequency energy is influenced mainly by the trace interval,and the larger the trace interval is,the more high-frequency energy is lost.The detection depth is influenced mainly by the array length and dispersion curve extraction method,and the influence of the trace interval on the detection depth is relatively small.The energy spectrum is focused and lower frequency dispersion points can be extracted more accurately by using the ESPAC(Extended Spatial Auto-Correlation)method and increasing the array length,thereby obtaining more accurate velocity values and deeper stratigraphic information.The longer the array length is,the greater the detection depth is,but as the array length increases,the growth rate of the detection depth slows down.As the array length and trace interval increase,the resolution of inversed shear wave velocity gradually decreases,and the resolution of the apparent shear wave velocity and surface wave phase velocity profiles also gradually decreases,in addition,the resolution of the inversion of the shear wave velocity,apparent shear wave velocity,and surface wave phase velocity profiles decreases sequentially.Therefore,it is necessary to select appropri
作者
马龙
张辉
董春芳
MA Long;ZHANG Hui;DONG Chunfang(Power China Beijing Engineering Corporation Limited,Beijing 100024,China;BGI Engineering Consultants Ltd.,Beijing 100038,China)
出处
《铁道科学与工程学报》
EI
CAS
CSCD
北大核心
2024年第11期4804-4814,共11页
Journal of Railway Science and Engineering
基金
国家重点研发计划资助项目(2021YFC3090302)。
关键词
微动勘探
线性排列
能量谱
探测深度
分辨率
microtremor exploration
linear array
energy spectrum
detection depth
resolution
