共查询到17条相似文献，搜索用时 187 毫秒
1.
高阻碳酸盐岩中的低阻断层和充水溶洞是岩溶区地下水勘查的主要目标体。根据高阻中找低阻的原则,建立碳酸盐岩类裂隙溶洞水赋存模式的断层－溶洞地电模型,利用RES3D软件进行温纳、施伦贝格、偶极－偶极三种采集装置的正反演模拟计算,从三维反演结果、剖面、电测深曲线三个维度,对比分析不同装置下断层－溶洞目标体的地电响应特征和规律。结果显示:(1) 探测深度内,温纳、施伦贝格、偶极－偶极装置可有效识别断层及其上盘三倍于电极距规模的充水溶洞,无法分辨断层下盘二倍于电极距规模的充水溶洞;(2) 相同模型和观测条件下,偶极－偶极装置对目标体的识别能力最强,其三维反演结果可识别溶洞下边界,剖面中形成左凸低阻圈闭异常,不同测深点的曲线类型、拐点、极值点与模型设计最为贴近,且拐点对应岩性界面,极值点位于地质体的中心深度。该工作对野外观测方式的选取和地质解译有一定指导意义。 相似文献
2.
高密度电法在反演过程中,电极距相比电性异常体横向长度过大时,电性异常体在反演中无法得到约束;某电极距下,当电性异常体埋藏深度增加大到一定深度时,在反演中电性异常体也无法得到约束。针对以上两个问题,利用res2dmod正演软件建立模型,再利用res2dinv反演软件对模型进行反演,通过对比分析结果表明:温纳、偶极和微分三种装置分两种情况:如果电极距小于20m模拟条件下,对于埋藏深度为5m且剖面面积不同的电性异常高阻体(异常体电阻率=100Ω·m,围岩电阻率=10Ω·m),横向反演分辨率,温纳装置大于微分和偶极装置;电极距小于12.75m时,微分装置大于偶极装置,电极距大于12.75m时,偶极装置大于微分装置。如果电极距在2m^8m范围内,对于剖面面积为4×4(m2)的电性异常高阻体(异常体电阻率=100Ω·m,围岩电阻率=10Ω·m),其最大约束深度随电极距的增大而先增大后减小;相同电极距下,偶极装置的最大约束深度>微分装置的最大约束深度>温纳装置的最大约束深度。 相似文献
3.
介绍了不对称测深法装置的测深原理;在吉林某地进行了激电测深勘探,结果显示:正向单极-偶极和反向偶极-单极采集的视电阻率、视充电率原始数据在拟断面图的分布特征,和大地电磁测深原始数据受到的静态效应类似,视电阻率、视充电率受局部地形和电磁噪声的影响,在拟断面图中呈假的带状异常。正向单极-偶极、反向偶极-单极装置获取的视电阻率、视充电率数据也可分别进行二维反演,但联合单极-偶极/偶极-单极装置测深二维反演地质结果最好,具有采集的数据量大、激电信号强 、穿透深度大、勘探精度高等优点,根据视电阻率、视充电率二维反演在地电断面成像技术,能够准确确定电性异常体的空间分布,为钻探验证电异常提供准确的地球物理依据。 相似文献
4.
海域环境对高密度电阻率法在仪器设备、测量技术和反演解译等方面提出了更高要求,开展海上高密度电法的数值模拟和实测研究将进一步丰富近岸海域地质、资源和环境等问题的勘查手段.基于数值模拟和野外实测,深入研究了偶极-偶极、温纳、斯贝等不同装置对近岸海域典型地电模型的分辨能力和空间定位效果,并详细分析了海水导电性的影响,最后在珠江口伶仃洋海域开展了国内首次2条长剖面的实际测量.结果表明海水电导率对不同测量装置在探测深度和精度方面存在差异化影响,井中电缆利用浮力材料固定后,进行水面拖缆式偶极-偶极测量能大幅降低海底沉缆式测量的施工风险,实现复杂海域环境下高密度电法探测效果、深度与效率的优化折中. 相似文献
5.
6.
通过对4种地电模型(单一正方体低阻地电模型、两个相邻低阻正方体地电模型、相邻低/高阻正方体地电模型、斜相邻低阻正方体地电模型)进行三极、二极、偶极等装置的正演计算,得出不同装置对低阻体的响应特征。结合工作实际,总结出不同岩溶形态的电剖面ρs曲线特征及ρs等值线平面、断面图等异常特征。对比野外施工常用的几种装置异常幅度及分辨能力等特征后,认为:野外施工时,一般采用温纳四极装置或三极装置探测地下水效果较为理想。通过湖南某高速公路服务区及广西某地大型果园的两个成功找水案例,说明高密度电法在灰岩地区找水中有显著效果。 相似文献
7.
二维高密度电阻率法数值模拟与应用 总被引：2，自引：0，他引：2
高密度电阻率法作为工程勘察领域广泛使用的勘察方法之一,与传统电阻率法相比,具有效率高、信息丰富等优点。本文首先从高密度电法原理出发,介绍了两种常见的装置（温施装置和温纳装置）的特点。然后依据实测资料建立了地电理论模型,并通过理论正反演数值模拟,分析了两种装置下模型的电性响应特征,并与实际资料与进行了比较,进而进行地层分层和地质解释。结果表明,温施装置进行地质分层效果更佳,通过高密度电法正演模拟指导反演可提高地层分层和地质解释的精度。 相似文献
8.
基于不同装置的二维高密度电法勘探效果比较与分析 总被引：1，自引：0，他引：1
为比较分析高密度电法不同装置对探测异常地质体的效果,通过建立高阻异常体和隐伏直立低阻体地电模型,正演计算了不同装置类型下的视电阻率,并加噪进行二维电阻率反演。各种装置的反演结果表明：在探测地下高阻异常体时,温纳α、β、γ装置优于其他装置,揭示异常位置与形态相对较好;对于隐伏直立低阻体而言,温纳p装置和三极装置探测效果好,其中温纳β为最理想装置,实例验证表明,温纳α、β、γ装置在探测地下防空洞时体现了其装置的优越性,验证了理论模拟结论的正确性。 相似文献
9.
10.
11.
相位激电测深在有色金属矿产勘查中的应用 总被引：2，自引：4，他引：2
激发极化方法一直是有色金属矿产勘查的主要手段,国内大多使用时间域激发极化方法,相位激发极化法应用较少。相位激电法采用选频测量,抗干扰能力相对较强,近些年在有色金属矿产勘查中一直使用相位激电测深方法,取得了较好的实际应用效果。在使用中,根据实际情况选用偶极-偶极或单极-偶极测量装置,其中偶极-偶极测量装置主要用于普查阶段,单极-偶极装置采用常规高密度电法的布极方式,主要用于详查阶段。这里以具有代表性的高阻高极化、低阻高极化矿体上的应用结果为例,说明偶极-偶极和单极-偶极装置相位激发极化测深的应用效果,以及在实际找矿工作中的作用。 相似文献
12.
The effectiveness of inversion apparent resistivity data to determine accurately the true resistivity distribution over 2D structures has been investigated using a common inversion scheme based on smoothness-constrained nonlinear least-squares optimization with enhancing horizontal resolution (EHR) technique by numerical simulation. The theoretical model generates in RES2DMOD software at specific distance and depth using Wenner, Wenner–Schlumberger, and pole–dipole arrays were inverted. The inversion model was compared with the original 2D model in RES2DINV software. The study model includes horizontal layering, vertical resolution, and horizontal two layers with different resistivity. Also, the response to variations in data density of these arrays was investigated. The study shows the best array suitable to be used in the survey was chosen for real data acquisition at the actual site. Subsequently, the results from borehole were used to verify the results of 2D resistivity imaging method with and without EHR technique. Saturated zone (0–40 Ω-m) was found scattered at the depth of 10–20 m. The borehole is located at 63 m at 2D resistivity imaging survey which shows at depth 10–20 m is sandy silt. Highly weathered sandstone was found at 6 m depth with resistivity value of 800 Ω-m and SPT N value of 20. The bedrock was found at 27 m depth with resistivity value of 3,000 Ω-m and SPT N value of 50. The application of 2D resistivity imaging with EHR technique indicate the ability of the proposed approach in terms of density, depth, and resistivity value of anomalous and layer in a computationally and numerically efficient manner and to exhibit good performance in the data inversion. 相似文献
13.
Prasenjit Das S. K. Pal P. R. Mohanty Piyush Priyam Abhay Kumar Bharti Rajwardhan Kumar 《Journal of the Geological Society of India》2017,90(2):169-174
Land subsidence is a serious problem in Indian coalfields due to old underground mine workings. Unfortunately, most of these are uncharted as no mine plans are available. The hidden galleries, goafs, shafts etc. may pose great threat for future mine development as well as to the local environment. The mine workings should be charted to undertake an effective preventive action. In the present study, 2D electrical resistivity tomography (ERT) technique has been used to detect underground mine workings, mainly air or water filled galleries. Initially, the whole exercise has been executed through a synthetic model study. Gaussian random noise of 5mV/A has been added with synthetic data to demonstrate field condition which provides realistic results. ERT survey was conducted over a part of Jogidih coal mine of Jharia coal field in India for a first time. Four electrode configurations, Wenner, Schlumberger, dipole-dipole and gradient were considered for this study. The results indicate the presence of sub-surface water and air filled cavity due to high resistivity contrast with surroundings. 相似文献
14.
为了提高电阻率法对地下介质污染问题的探测能力,分析了含油污水污染地下介质后引起的导电性变化,建立了适用于该问题分析的地电模型。利用2.5维有限元的方法正演模拟了采用温纳、施龙贝格、偶极和二极装置监测时所得的典型电异常剖面。正演模拟结果显示不同装置对污染区的反映能力不同,相对而言施龙贝格和温纳装置对污染区分布的反映较为直观。饱和粘土的含油污染区用温纳装置测量,剖面上表现为相对高阻异常特征,异常区域分布和污染通道相吻合。应用实例也证实了这一分析。 相似文献
15.
In this article, we present an interesting behaviour of conductance in a basaltic terrain. We use vertical electrical sounding data carried out in Wenner configuration at dug well sites for data analysis. Geophysical phenomena observed in the sharply rising trends followed by negligibly rising trends of the conductance curves are discussed. The unique behaviour of conductance curve is used to estimate depth to the static water level in dug wells. The geophysically estimated depths to the static water levels are compared with the observed static water levels in the existing dug wells located at all sites of investigation. Water-level fluctuations observed in dug wells between two different periods coinciding with pre- and post-monsoon regimes are geophysically estimated by using the trends on the conductance curves. Depth to the static water levels is geophysically estimated at seven experimental sites located adjacent to dug wells and four virgin sites where there are no dug wells. Validation of the geophysically estimated static water levels and static water-level fluctuations shows encouraging results. 相似文献
16.
S xxxV Suryanarayana Rao S Murali V L S Bhimasankaram 《Journal of Earth System Science》1981,90(1):75-83
A new variant of the four-electrode system is proposed for geophysical resistivity investigations, particularly for profiling over conductive bodies. Model tank resistivity profiling experiments with Wenner, Schlumberger and the proposed T-shaped four-electrode arrays were carried out over a thin conducting vein type model to evaluate the efficacy of the new array. The proposed array appears to possess a larger response, a greater depth of investigation and a higher vertical resolution in detecting conducting bodies, as compared to the two-conventional arrays. 相似文献
17.
岩溶是某垃圾焚烧环保发电站场场址勘察的主要不良地质作用,为了查明岩溶和破碎带的分布情况,本文利用高密度电阻率法来探测能引起低阻异常的岩溶等地质体。在调查该区地层和溶洞的类型、分布及电性特征的基础上,利用RES2Dmod建立包含不同规模和埋深的低阻溶洞或破碎带模型,通过对比模型的温纳、偶极和微分三种装置类型的正反演结果,在本地区选用分辨率和稳定性高的温纳装置进行高密度勘测。利用高密度电阻率法查明了两个落水洞的埋深和分布情况,推测了4个疑似溶洞和破碎带,部分与后期验证钻孔吻合。利用合适的装置类型进行高密度探测可以查明充水充泥低阻溶洞的规模及分布,是一种经济有效的场址勘察方法。 相似文献