摘要
宝昌台EW、NS测道地电阻率在2009年11月出现了显著的短时间下降变化,随后迅速恢复,EW测道自2010年2月底开始大幅下降,经现场落实认为这些变化与2009年11月中国移动公司在测区埋设的钢缆有关,2011年7月26日和27日经台站和中国移动公司协商后移除了部分钢缆,两测道的地电阻率观测值得到恢复.建立三维有限元模型计算了表层土壤处于非稳定冻结、稳定冻结和完全融通三个阶段钢缆对地电阻率观测的影响,计算得到:在稳定冻结阶段钢缆对观测的影响非常小,完全融通阶段的影响最大,非稳定冻结阶段的影响介于二者之间,且三个阶段计算得到的地电阻率变化值与观测值相吻合,从数值分析的角度确定了钢缆对宝昌台地电阻率观测的干扰.
The geoelectric resistivity observation data of EW and NS directions in Baochang station distinctly decreased in Nov. 2009, decrease duration was very short, and the disturbed observation quickly recovered afterward. Large decrease occurred in EW direction since the end of Feb. 2010, and field investigation suggested that the decreased variations in 2009 and 2010 were correlated with wirerope burned in the observation field by China Mobile Communication Corporation. The main part of burned wirerope was removed on July 26th and 27th, 2011, after negotiation between Baochang station and China Mobile, and geoelectric resistivity observation data of two directions approximately recovered to the level of observation with no wirerope. A three-dimensional finite element model was constructed to analyze the disturbance caused by wirerope in observation field. Since the surface soil was frozen in winter, and re~,dstivity of surface soil played a major role in the disturbance caused by wirerope, so three states of unstable freeze, stable freeze and complete thaw were calculated in this study to determine the impact of wirerope on observation. Results of model calculation suggested that disturbance caused by wirerope was very small in state of stable freeze and was most conspicuous in state of complete thaw, disturbance in state of unstable freeze would come somewhere in between. The computed geoelectric resistivity variations in three states agreed with observation, so the disturbance caused by burned wirerope in Baochang geoelectric resistivity station was demonstrated from view of numerical analysis.
出处
《地球物理学进展》
CSCD
北大核心
2013年第2期727-734,共8页
Progress in Geophysics
基金
国家科技支撑计划项目(2012BAK19B02-03)
中国地震台网中心青年基金(1212)资助
关键词
宝昌台
地电阻率
钢缆
干扰
Baochang station, geoelectrical resistivity, wirerope, disturbance
