地下井体建设对地磁观测场地的干扰  

The interference of underground well construction on geomagnetic observation field

作　　者：王晓睿 王淑辉 刘允 张帅 代青沁 WANG Xiaorui;WANG Shuhui;LIU Yun;ZHANG Shuai;DAI Qingqin(Liaoning Seismic Station,Shenyang 110034,China;Dalian Seismic Monitoring Center Station,Liaoning Province 116021,China;Shenyang Seismic Monitoring Center Station,Liaoning Province 110000,China)

机构地区：[1]辽宁地震台,沈阳110034 [2]大连地震监测中心站,辽宁116021 [3]沈阳地震监测中心站,辽宁110000

出　　处：《地震地磁观测与研究》2023年第2期112-118,共7页Seismological and Geomagnetic Observation and Research

基　　金：辽宁省青年基金(项目编号:LZ201903)。

摘　　要：以大连地震监测中心地震前兆观测新建地下井体为例,基于场地梯度测量方法,定量分析井体建设对地磁观测场地的干扰。基于观测井设计数据,计算其理论干扰距离,发现最大干扰距离s=456.6 m>270 m(二者的实际间距),推测此地下井体会对地磁观测产生干扰。以井体与地磁观测仪器室之间50 m×160 m的范围为测量区域,以10 m×10 m的网格进行测线及测点的布设,计算并对比分析井体建设前后各测线地磁总场强度F的梯度值,结果发现,除个别临近办公区的测点梯度值不稳定,其他测点梯度值基本处于重合状态,排除测量区域葡萄架和接线井的干扰后,磁场梯度整体符合规范,即ΔF_(b)≤1 nT/m。分析认为,地下井体对地磁场的最大干扰距离为160 m,表明该中心地下井体建设不会对地磁观测场地造成干扰。Taking the newly built underground well body for earthquake precursor observation at Dalian Seismic Monitoring Center Station as an example,based on the site gradient measurement method,this study quantitatively analyses the interference of well construction on geomagnetic observation sites.Based on the design data of the observation well,we calculate its theoretical interference distance.It was found that the maximum interference distance s=456.6 m,which is greater than 270 m(the actual distance between the two).It is speculated that these underground wells may interfere with geomagnetic observations.We select a range of 50 m×160 m between the well body and the geomagnetic observation instrument room as the measurement area.Using a 10 m×10 m grid to lay out survey lines and survey points,we calculate and compare the gradient values of the total geomagnetic field intensity F of each measuring line before and after the completion of the wells.The results show that,except for some unstable gradient values at measuring points near the office area,the gradient values of other measuring points are basically in a coincident state.After eliminating interference from the grape frame and wiring well in the measurement area,the overall magnetic field gradient meets the specifications,namely ΔF_(b)≤1 nT/m.Analysis suggests that the maximum interference distance of underground wells on the geomagnetic field is 160 m.This indicates that the underground well construction of the center will not cause interference to the geomagnetic observation site.

关 键 词：地磁观测场 场地梯度 井体干扰 干扰距离 

分 类 号：P315.721[天文地球—地震学]