摘要
地壳高导异常及各向异性成因是地学研究的热点之一,断裂带区域常呈现出高电导率特征,对于石墨富集的断裂带,石墨形态及分布对导电性的影响已经引起关注.本文利用有限元数值模拟方法,构建了石墨-石英三维模型,探讨了石墨含量、排列方式、孔隙度及温度对模型电导率的影响.结果表明,石墨连通前,温度的增加能使模型电导率显著增大,而在石墨连通后,石墨含量的增加、片状石墨沿导电方向的定向排列以及石墨直径与厚度比值的增大,均能导致模型电导率发生显著增加,孔隙度的增大则导致模型电导率减小.同时,这些参数的变化也会使模型电导率突变时的石墨含量阈值发生改变,当石墨排列方向改变时,这一阈值变化显著,对于石墨富集的一些断裂带区域,石墨定向排列可能是引起高导的一种成因.
The causes of high conductivity anomalies and anisotropy are one of the focused issues in geosciences.Fault zones often exhibit characteristics of high conductivity.With regard to some graphite-rich fault zones,the influence of graphite morphology and distribution on conductivity has attracted attention.In this work,mineral-mixed models of graphite and quartz were constructed,and the finite element numerical method was used to examine the effect of graphite content,arrangement,temperature and porosity on the conductivity of the assemblage models.Results show that when the graphite particles are isolated from each other,the electrical conductivity of the model increases significantly with the increasing temperature.As graphite particles are connected,the conductivity increases with growing graphite content;the arrangement is oriented in the conductive direction and the ratio of graphite diameter to thickness increases.However,the increase in porosity leads to a decrease in model conductivity.The graphite content threshold also changes with these parameters and varies obviously with changes in the direction of graphite arrangement.For some graphite-rich faults,the orientation of graphite may be a cause of high conductivity.
作者
郭颖星
朱涛
郑军
GUO YingXing;ZHU Tao;ZHENG Jun(Institute of Geophysics,China Earthquake Administration,Beijing 100081,China;Chinese Academy of Geological Sciences,Beijing 100037,China)
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2021年第11期4031-4042,共12页
Chinese Journal of Geophysics
基金
国家自然科学基金项目(41804087)
中国地震局地球物理研究所基本科研业务费专项(DQJB20X10)
科技部国家重点研发计划(2017YFC1500205)共同资助.
关键词
石墨-石英模型
电导率
数值模拟
定向排列
孔隙度
Graphite-quartz model
Electrical conductivity
Numerical simulation
Orientation arrangement
Porosity
