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1.
复杂条件下地下水磁共振探测与灾害水源探查研究进展   总被引:4,自引:0,他引:4  
磁共振地下水探测是一种直接非侵害性探测地下水的地球物理新方法,与传统地球物理探测地下水方法相比,具有高分辨力、高效率、信息量丰富和解唯一等优点。近年来地下水磁共振探测技术发展迅速,不仅用于缺水地区的地下水勘查,还在地下灾害水源(由于地下水引起的灾害如堤坝渗漏、隧道/矿井水害、滑坡、海水入侵等)的探测预警中进行了探索性研究。综述了复杂条件下地下水磁共振探测技术的研究现状,包括强电磁干扰环境的自适应噪声压制、地下小水体的2D/3D磁共振探测、复杂条件的数据处理与反演、针对喀斯特地貌等地质环境的地下水磁共振与瞬变电磁联合探测研究成果,简要介绍了磁共振技术用于滑坡、海水入侵和隧道涌水等灾害水源探查的探索性研究示例,展望了地下水磁共振探测技术的未来发展趋势。  相似文献   

2.
Identification of damages/changes that are affecting the underground water quality due to the effect of anthropogenic activities is often done after environmental problems have become evident or water portability being strongly affected. Two main applications of electrical resistivity tomography (ERT) methods have been addressed covering characterization of leachate movement from a composting area of a Sugar Mill in Southern India. Good correlation has been obtained between ERT and groundwater quality assessments as well as from groundwater monitoring data sets. The study helped in conceptualization of hydrogeologic framework in basaltic terrain. Impacts on groundwater regime associated with urbanization and industrialization can easily be assessed through the variation of resistivity in the inverse resistivity pseudo-section model of the ERT investigations. Assessment of groundwater potential in an upcoming Urban Node, Greater Hyderabad city has been illustrated in the second example. Identification of good thickness of weathered regolith for location of water harvesting through Green Fingers evolved. The small infrastructure would help carrying of enhanced surface runoff as well as to sustain groundwater yield in the urban node and thereby ensuring sustainable groundwater resource exploitation. The above studies have illustrated immense potential of the ERT tools in the assessment of groundwater contamination as well as groundwater potential.  相似文献   

3.
航空物探在水工环勘查中具有覆盖面积大、速度快、周期短等特点,到目前为止,已经完成了多个测区的生产测量和成果解释工作,并取得了明显的勘查效果。根据以往国内航空物探在水工环方面的勘查效果,并分析国际上近年来利用航空物探进行水工环勘查的实例,提出了航空物探在水工环勘查领域的优势和应用前景。  相似文献   

4.
Two geophysical techniques were integrated to map the groundwater aquifers on complex geological settings, in the crystalline basement terrain in northeast Nuba Mountains. The water flow is structurally controlled by the northwest–southeast extensional faults as one of several in-situ deformational patterns that are attributed to the collision of the Pan-African oceanic assemblage of the Nubian shield against the pre-Pan African continental crust to the west. The structural lineaments and drainage systems have been enhanced by the remote sensing technique. The geophysical techniques used are: vertical electrical soundings (VES) and electrical resistivity tomography (ERT), in addition to hydraulic conductivity measurements. These measurements were designed to overlap in order to improve the producibility of the geophysical data and to provide a better interpretation of the hydrogeological setting of the aquifer complex structure. Smooth and Block inversion schemes were attempted for the observed ERT data to study their reliability in mapping the different geometries in the complex subsurface. The VES data was conducted where ERT survey was not accessible, and inverted smoothly and merged with the ERT in the 3D resistivity grid. The hydraulic conductivity was measured for 42 water samples collected from the distributed dug wells in the study area; where extremely high saline zones were recorded and have been compared to the resistivity values in the 3D model.  相似文献   

5.
Self potential (SP) and electrical resistivity tomography (ERT) methods are used together with the results of groundwater samples hydrogeochemical analysis to assess the impact of the water leak from the landfill garbage site at NamSon located in Northern Hanoi on causing pollution to the surrounding environment and affecting geological structure. Selected survey area covers an area of 180 × 300 m lying in the low land of the NamSon site with a slope ranging about 8 m in direction NW–SE. There are three geophysical measurements lines denoted as T1, T2 and T3. Processing 180 SP data points has allowed to draw maps of equipotential epoch in the two periods in 2015 and 2016. The maps show four zones of SP positive anomalies with maximum amplitudes of about +20 mV where the groundwater flow direction is downward and five zones of SP negative anomalies with minimum values in a range from ?180 to ?260 mV where the groundwater flow direction is upward. Resistivity values of the subsurface layers of soils and rocks have been aquired from 2D inverse model for measuring ERT in March 2015 and March 2016. The results of the ERT allowed to define the low resistivity in the range 15–20 Ωm related to leachate plume from NamSon landfill site. Results of the physico-chemical analysis of groundwater samples from the existing six boreholes show increases in concentration of the measured pollutant parameters indicating contamination of the groundwater as a result of solid waste leachate accumulation. This result is affirmative evidence for the survey results by geophysical technique. The rapid decrease in quality of groundwater over the last year is probably due to the influence of the leachate from the NamSon landfill site.  相似文献   

6.
山岭隧道工程具有隐蔽性、施工复杂性、地层条件和周围环境不确定性等特点,采用科学的勘察方法,是查明隧道岩土体工程地质条件的有效手段。本文以海淀区西山隧道为依托,针对隧道工程勘察中的关键地质问题,运用工程地质测绘、钻探、工程物探、水文地质勘查等综合勘察方法,有效地查明隧址区的地质构造、岩土体结构和地下水分布特征,全面、客观地评价隧道进出口段边坡及仰坡稳定性、隧道围岩质量与稳定性、隧道涌水量、地应力及有害气体等工程地质问题,并针对不良地质现象提出防治对策,以期为工期紧张、地形困难且日趋增多的山岭隧道工程地质勘察,提供可以借鉴的模式和方法。  相似文献   

7.
The increasing demand for freshwater has necessitated the exploration for new sources of groundwater, particularly in hard rock terrain, where groundwater is a vital source of freshwater. A fast, cost effective, and economical way of exploration is to study and analyze geophysical resistivity survey data. The present study area Omalur taluk, Salem District, Tamil Nadu, India, is overlain by Archaean crystalline metamorphic complex. The study area is a characteristic region of unconfined aquifer system. The potential for occurrence of groundwater in the study areas was classified as very good, good, moderate, and poor by interpreting the subsurface geophysical investigations, namely vertical electrical soundings, were carried out to delineate potential water-bearing zones. The studies reveal that the groundwater potential of shallow aquifers is due to weathered zone very low resistivity and very high thickness and the potential of deeper aquifers is determined by fracture zone very low resistivity and very high thickness area. By using conventional GIS method, the spatial distribution maps for different layer (top soil, weathered zone, first fracture zone, and second fracture zone) thicknesses were prepared. The geoelectrical approach was successfully applied in the study area and can be therefore easily adopted for similar environments.  相似文献   

8.
自然电场法梯度测量是一种原理看似简单,但实际操作却较为困难的地球物理方法。自然电场法对物理性质差异较大的物体有着敏感的反应。自然电场曲线所包含的信息即包括了地下异常信息,同时又包括地形高程等影响信息。实践证明,对于高程变化较大的地区,自然电场曲线经过地形高程等校正之后,才能更为准确的反应地下异常信息。  相似文献   

9.
国外勘查地球物理的若干进展——1996年   总被引:1,自引:1,他引:0  
本文根据1996年国外发表的勘查地球物理文献,概要列举了物探方法发展的新前沿。在矿产勘查方面介绍了金属矿预测和普查工作的新进展以及金伯利岩、滑石矿床的找矿方法和实例。在环境勘察方面,回顾了电法在水质调查中的应用,介绍了物探方法在城市垃圾场调查、煤矿闭坑善后工作、城市人工物理场环境效应调查中的应用以及滑坡和洞穴调查中新采用的方法。在区域和深部地球物理调查方面,概述了西方国家近年来实施的矿产勘查开创计划、大规模的电导率结构研究和南极磁异常图的编制。在新技术新方法方面,介绍了新的航空电磁系统———FLAIRTEM、电(磁)法中非接触数据采集技术、谱激发极化法在环境调查中的应用、探测油气蚀变柱的区域勘查新方法和海洋重力仪。  相似文献   

10.
在缺水地区开展找水水文地质勘查工作,如何提高成井供水效率,科学的找水方法至关重要。笔者介绍近10年来在我国西部地区300多个缺水村镇找水水文地质勘查实践中,总结出"逐步逼近式"找水方法。主要包括利用前人调查成果通过预研究确定找水方向、应用遥感解译方法圈定找水靶区、辅以简易快速物探方法的中比例尺地面调查确定富水地段、详细地面调查与物探组合技术结合优化确定钻探孔位、不同含水层选择相应钻探方法和成井工艺5个步骤。以及针对不同找水区在遥感数据源选择、简易快速物探方法应用与多方法有效组合探测的技术要点。  相似文献   

11.
综合电法在太行山区地下水勘查实例解析   总被引:1,自引:1,他引:0       下载免费PDF全文
介绍了利用大功率激发极化法、超高密度电法和音频大地电磁法等物探方法在太行山区抗旱找水工作的实例;就太行山变质岩、灰岩地区地质条件的特殊性,针对性地提出了地球物理的解决方法和思路。在利用已得到的地球物理勘探结果研究水文地质问题的过程中,介绍了以电法为主的几种地球物理方法技术及地下水勘查工作过程;针对不同水文地质情况下利用这些方法技术在应用中面临的难题,总结了成功与失败的勘查经验。针对已有地质资料的局限性和变质岩区含水层结构的特殊性,总结出了一套行之有效且推广性较强的交直流电法相结合的综合电法勘探方式。
  相似文献   

12.
Previous time-lapse Electrical Resistivity Tomography (ERT) studies have experienced difficulties in reconstructing reliable calculated resistivity changes in the subsurface. Increases or decreases of resistivity appear in the calculated ERT image where no changes were noted in the subsurface, leading to erroneous hydrological interpretations of the geophysical results. In this article, we investigate how a variation of actual resistivity with time and at shallow depth can influence time-lapse ERT results and produce resistivity artefacts at depth. We use 1 and 2-D numerical modelling to simulate infiltration scenarios. Using a standard time-lapse inversion, we demonstrate the resistivity artefact production according to the electrode spacing parameter. We used an advanced inversion methodology with a decoupling line at shallow depth to attenuate or remove resistivity artefacts. We also applied this methodology to a field data set obtained in a semi-arid environment in Burkina Faso, West Africa. Here, time-lapse ERT shows several resistivity artefacts of calculated resistivity if a standard inversion is used. We demonstrate the importance of a dense sampling of shallow resistivity variations at shallow depth. Advanced interpretation allows us to significantly attenuate or remove the resistivity artefact production at intermediate depth and produce reliable interpretation of hydrological processes.  相似文献   

13.
发育深度、充填物、展布方向等岩溶发育特征是在高山峡谷地区进行桥址区地球物理勘察时需要重点考虑的问题,受风化物、岩层、地下水和地形等因素影响,很难得到满意的地球物理勘察信息.某悬索桥建于岩溶发育的高山峡谷地区,为了提高勘察效率,采用浅层地震、音频大地电磁、对称四极测深3种地球物理勘察方法,勘察精度依次提高,勘察内容相互印...  相似文献   

14.
Earth Fissures in Wadi Najran,Kingdom of Saudi Arabia   总被引:1,自引:0,他引:1  
The formation of earth fissures due to groundwater depletion has been reported in many places in North America, Europe, and Asia. Najran Basin is in the southern part of the Kingdom of Saudi Arabia, and agricultural activities and other groundwater uses have caused significant groundwater depletion there. The basin recently experienced a sudden appearance of numerous earth fissures. An interdisciplinary study consisting of an evaluation of land-use changes, and hydrological, hydrogeological, and geophysical investigations was conducted to determine the reason for the formation of the earth fissures. The hydrological analysis strongly revealed that the groundwater level is decreasing with time. Groundwater depletion would lead to the accumulation of subsurface stress, causing soil hydro-consolidation which creates the ideal condition for the formation of earth fissures. Electrical resistivity, data indicated that there are anomalies in the profiles, which are most probably due to the presence of subsurface topography, another key factor for the formation of the earth fissures.  相似文献   

15.
The aim of this work is the joint application and integration of non-invasive geoelectrical methods for studying the landfill of Savoia di Lucania (Southern Italy). This landfill for its engineering features and small dimensions (70 m × 30 m × 6 m) represents an optimal test site to assess a geophysical survey protocol for municipal solid waste landfills investigation and monitoring. The landfill of Savoia di Lucania has been built with a reinforced concrete material and coated with a high-density polyethylene (HDPE) liner. Three electrical resistivity tomographies (ERT), two self-potential (SP) map surveys and one induced polarization (IP) section have been performed, both in the surrounding area and inside the waste landfill. The geophysical investigations have well defined some buried boundaries of the landfill basin and localized the leachate accumulation zones inside the dumpsite. Comparison of our results with other engineering and geological investigations could be the key for evaluating the integrity of the HDPE liner. Finally, the joint use of the ERT, IP and SP methods seems to be a promising tool for studying and designing new monitoring systems able to perform a time-lapse analysis of waste landfill geometry and integrity.  相似文献   

16.
文章指出物探方法的特点是工作场地要求低、周期短、耗资小、效果直观,并论证在解决工程地质问题中物探技术与传统勘探方法的关系,即两者相互依靠、相互补充、不可分割。只有认清两者的关系才能更好地解决工程地质问题。  相似文献   

17.
物探技术在我国多年冻土勘测中的应用   总被引:14,自引:7,他引:7  
俞祁浩  程国栋 《冰川冻土》2002,24(1):102-108
现代物探技术在冻土勘查和研究中始终发挥着重要的作用.40a来通过不断努力,我国冻土物探事业的发展历经了从无到有、从手段简单到方式多样、单一物探参数到多参数反映冻土诸多特征的发展历程.通过物探手段在不断提高冻土类型识别和划分精度等方面均取得了长足的进步,现已成为我国多年冻土勘察、动态监测、变化规律认识和环境工程地质评价等研究中的关键手段之一.文章分别就地球物理勘测方法在我国寒区中的应用、研究、现状,国际开展相关的研究内容和我国在相关研究领域中的地位、存在问题及今后发展方向等方面进行了概括论述。  相似文献   

18.
A geophysical investigation of a landfill area was conducted as inextricable phase of a preliminary geotechnical, geological and hydrogeological study of the area under investigation. Electrical resistivity tomography (ERT), one of the most promising prospecting techniques mainly concerning its effective contribution to resolve several environmental problems, was applied for the geophysical modeling. ERT is a robust imaging method the theory and implementation of which are well documented in geophysical research literature. The survey site is located in Akrotirion Peninsula, about 7 km east of Chania city in Crete I. The geological setting comprises Trypalion limestones, marly limestones and a clayed weathered layer. Cavities are also identified at various scales which are recent tectono-karstic voids. Due to the above-mentioned geological singularity and in the light of the requirement for an environmentally safe construction of the landfill, an ERT survey was carried out. Specifically, seven geoelectrical tomographies were conducted reaching the prospecting depth of 36 m. The resulted images conduced, to overcome geotechnical problems since the spatial distribution of karstic voids was determined, to plan the future sites for waste disposal as the geological conditions were studied in detail and to reliably estimate the thickness of the already deposited wastes. The resulted images were confirmed using available borehole logs and ambient noise measurements.  相似文献   

19.
An integrated electromagnetic (EM) and seismic geophysical study was performed to evaluate non-invasive approaches to estimate depth to shallow groundwater (i.e., < 5 m) in arid environments with elevated soil salinity, where the installation of piezometers would be limited or prohibited. Both methods were tested in two study areas, one serving as a control site with relatively simple hydrogeology and the other serving as the experimental site with complex hydrogeology. The control site is located near the shore of Utah Lake (Palmyra, Utah, USA) where groundwater is shallow and unconfined in relatively homogeneous lacustrine sediments. The experimental site is in Carson Slough, Nevada, USA near the Ash Meadows National Wildlife Refuge in Amargosa Valley. Carson Slough is underlain by valley fill, with variable shallow depths to water beneath an ephemeral braided stream system. The geophysical methods used include frequency domain electromagnetic induction with multiple antenna–receiver spacings. High-resolution P-wave seismic profiles using a short (0.305 m) geophone spacing for common depth-point reflection stacking and first arrival modeling were also acquired. Both methods were deployed over several profiles where shallow piezometer control was present. EM results at both sites show that water surfaces correspond with a drop in conductivity. This is due to elevated concentrations of evaporative salts in the vadose zone immediately above the water table. EM and seismic profiles at the Palmyra site accurately detected the depth to groundwater in monitoring wells, as well as interpolated depths between them. This demonstrates that an integrated approach is ideal for relatively homogeneous aquifers. On the other hand, interpreting the EM and seismic profiles at Carson Slough was challenging due to the laterally and vertically variable soil types, segmented perched water surfaces, and strong salinity variations. The high-resolution images and models provided by the geophysical profiles confirm the simple soil and hydrological structure at the Palmyra site as well as the laterally complex structure at Carson Slough. The integrated approach worked well for determining depth to water in the geologically simple site, but was less effective in the geologically complex site where multiple water tables appear to be present.  相似文献   

20.
尖山营特大桥桥墩每年均出现雨季抬升,旱季沉降的异常现象。本文针对桥墩异常升降问题,采用野外地质调绘、现场监测、钻探、物探以及室内试验等方法相结合,分析造成尖山营特大桥墩体异常升降的主要原因。通过现场地质调绘和钻孔岩芯发育情况获取研究区地质构造分布,分析构造作用对异常升降的影响;基于天然音频大地电法勘探与对研究区地表水出露情况的勘察,研究承压水的赋存情况;将钻孔岩芯进行室内膨胀特性试验,研究了桥址区地基岩土体的吸水膨胀特性对桥墩升降的潜在作用。结果表明:排除地质构造和承压水原因,引起桥墩异常升降的主要原因是膨胀岩土体与地下水物理化学反应带动上部结构抬升及沉降引起的。桥址区二叠系吴家坪组(P2w)地层岩土体的膨胀力试验预估值在3~59 MPa之间,上部总荷载1.38~13.5 MPa,膨胀力大于上部结构重力载荷;原状膨胀岩试样在1.05 MPa的轴压作用下吸水,存在0.35%的膨胀应变,结合已有研究可确定130 m厚的膨胀性地层可造成上部结构抬升45.5 mm。二叠系吴家坪组(P2w)地层的吸水膨胀、失水收缩性能,与地下水的补给与排泄相结合,是引发桥墩异常升降的主要原因。  相似文献   

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