Research and application of comprehensive electromagnetic detection technique in spontaneous combustion area of coalfields

Perplexed by severe disasters, spontaneous combustion areas of coalfields in China not only lose a large number of precious coal resources but damage the ecological environment badly. The premise of effective control against the disasters is investigations on the source position and scope of spontaneous combustion areas at coalfields so as to provide scientific basis for fire extinguishment design and construction of coalfields. Working principles, construction methods and detection effects of high resolution earth resistivity method, transient electromagnetic method (small loop-center probe device) applied in the detection of combustion areas at coalfields have been introduced. The application shows that the above mentioned methods can detect the accurate position of underground combustion areas, are effective ones in detecting the combustion center, combusted area and distribution scope of combustion areas at coalfields, and have broad application prospects.     

高密度电阻率法在排石场稳定性评价中的应用

简述了高密度电阻率法的工作原理。在将高密度电阻率法实际应用于排石场的稳定性评价中时,根据各种装置的特点和T、λ参数对高低电阻率的表征特性,进行了多装置及多参数的探测。通过对各二维反演视电阻率成果图的综合对比和解释,划分出了存在地质隐患的区段。经钻孔验证,效果很好。结果表明通过高密度电阻率法多装置、多参数勘探,可以确定地下介质的电阻率及其电阻率特征,进而对排石场的稳定性做出评价,对同类地质情况的监测、预警,也是行之有效的。     

CHARACTERIZATION OF GROUND WATER FLOW FROM SPRING DISCHARGE IN A CRYSTALLINE ROCK ENVIRONMENT1

ABSTRACT: Recent investigations describing the hydrogeology of the Blue Ridge Province of Virginia suggest the occurrence of multiple aquifers and flow paths that may be responsible for the variable flow behavior of springs and seeps appearing throughout the region. Deep, confined aquifers associated with ubiquitous faults and shallow, variably confined saprolite aquifers may contribute water to spring outlets resulting in significantly different quantities of discharge and water quality. Multiple analyses are required to adequately identify the flow paths to springs. In this investigation, hydrograph analyses, surface electrical resistivity surveys, aquifer tests, and nitrate concentrations are used in conjunction with previously reported analyses from borehole logs and age dating of ground water to identify two distinct flow paths. Results indicate that base flow occurs from a deep fault zone aquifer and such discharge can be maintained even during prolonged periods of drought, while increased discharge identified on hydrograph peaks suggests the occurrence of rapid flow through the saprolite aquifer within a radius of about 25 meters of the spring orifice. Springflow hydrograph analysis is suitable for rapid characterization of flow paths leading to spring outlets. Rapid characterization is important for evaluation of potential water quality problems arising from contamination of shallow and deep aquifers and for evaluation of water resource susceptibility to drought. The techniques evaluated here are suitable for use in other locations in fractured crystalline rock environments.     

南黄海6.1级地震前江苏地电台站地电阻率异常分析

南黄海海域６．１级地震发生前，对海安台Ｎ３０°Ｗ、Ｎ７０°Ｗ、Ｎ６０°Ｅ三组测向和南京台ＥＷ向测向地电阻率负异常时段进行了３１日低通滑动平均滤波计算，发现异常突出，并超过二倍中误差，经分析认为对地电阻率所出现的中长期异常时段，不能轻易否定，必须不断跟踪分析     

南黄海6-1级地震前海安台形变电阻率异常特征

追踪研究南黄海６－１ 级地震前,松散覆盖层巨厚地区形变电阻率异常特征。探讨形变电阻率在破坏性地震前兆跟踪中的作用。     

城市地铁岩溶隐患多孔电阻率联合成像技术研究*

为有效解决二维电法在探测异常体空间形态上的不足,基于有限差分算法,建立溶洞与跨孔电阻率组合模型,探讨溶洞剖面投影位置及偏移距与电阻率响应变化特征,将跨孔电阻率数据体进行跨孔三维联合反演成像。结果表明:溶洞模型距跨孔探测剖面较近时,实际投影至剖面上位置不同,导致探测效果差异较大;随溶洞模型偏移距增大,溶洞投影中心位置电阻率整体表现为前期缓慢、中期迅速、后期减缓并最终趋于稳定的非线性变化趋势,溶洞模型旁侧效应影响范围约8 m。三维联合反演结果能立体可视化展示溶洞空间发育形态,在城市地铁超前地质灾害精准探测方面具有一定应用价值。     

基于电阻率的硫酸污染水泥土检测方法的探讨

电阻率法作为一种简单有效的测试方法,已在岩土工程检测中得到了一定程度的应用.通过室内试验模拟了水泥土试块受不同浓度硫酸溶液污染的反应,采用电阻率法研究了孔隙水电阻率、水泥土电阻率、结构因子与溶液浓度和龄期之间的关系.结果表明,孔隙水和水泥土电阻率随溶液浓度增大而减小、随龄期的增大而增大,结构因子随着溶液浓度和龄期的增加而增加,它们之间具有较高的相关性.这充分说明,电阻率法可应用于硫酸污染水泥土的检测和评价.     

台安地电阻率中等地震前兆异常判定

利用“地震预报实用化攻关软件”研究总结１９９４年９月～１９９５年４月辽宁省境内发生的三次中等地震前台安站地电阻率观测资料,揭示了短期前兆异常特征。通过用月距平方法,滑动富氏分析方法和灰色拓扑预测方法进行数据处理,进一步对前兆异常加以验证,并简要地分析了异常产生的原因。     

静力触探技术在宿迁市枣林医院工程地质勘察中的应用

结合宿迁市枣林医院岩土工程勘查项目,重点阐述了静力触探的成果指标ps 、fs、qc在该地区的地层分层、地基承载力估计、压缩模量估计和天然重度估计方面的应用,与土工试验相对照,结果表明利用静力触探方法得到的工程地质重要参数具有实际意义.     

临近空间环境探空火箭膨胀落球探测技术

针对临近空间大气环境探测需求,介绍了一种可用于30~100 km临近空间大气密度、风场、温度和气压的原位探测技术——探空火箭膨胀落球探测技术,阐述了其探测原理、系统组成和探测过程,采用仿真方法模拟了膨胀落球的探测数据,并利用模拟探测数据成功反演了30~100 km临近空间大气密度、风场、温度和气压等大气产品。该技术具有探测要素多、探测高度范围广、载荷成本低、设备较为简单等特点,对于我国临近空间环境探测和环境研究具有重要意义。