Obtaining 2D Soil Resistance Profiles from the Integration of Electrical Resistivity Data and Standard Penetration Test (SPT) and Light Dynamic Penetrometer (DPL) Resistance Tests—Applications in Mass Movements Studies

In Brazil and various regions globally, the initiation of landslides is frequently associated with rainfall;yet the spatial arrangement of geological structures and stratification considerably influences landslide occurrences. The multifaceted nature of these influences makes the surveillance of mass movements a highly intricate task, requiring an understanding of numerous interdependent variables. Recent years have seen an emergence in scholarly research aimed at integrating geophysical and geotechnical methodologies. The conjoint examination of geophysical and geotechnical data offers an enhanced perspective into subsurface structures. Within this work, a methodology is proposed for the synchronous analysis of electrical resistivity geophysical data and geotechnical data, specifically those extracted from the Light Dynamic Penetrometer (DPL) and Standard Penetration Test (SPT). This study involved a linear fitting process to correlate resistivity with N10/SPT N-values from DPL/SPT soundings, culminating in a 2D profile of N10/SPT N-values predicated on electrical profiles. The findings of this research furnish invaluable insights into slope stability by allowing for a two-dimensional representation of penetration resistance properties. Through the synthesis of geophysical and geotechnical data, this project aims to augment the comprehension of subsurface conditions, with potential implications for refining landslide risk evaluations. This endeavor offers insight into the formulation of more effective and precise slope management protocols and disaster prevention strategies.

Simulation of seafloor electrical resistivity measuring equipment based on 3D finite element method

In order to explore the mineral resources buried in sea mud,it is necessary to use seabed resistivity measuring equipment,which works closer to the sediments than ordinary ship-based geophysical measuring equipment. Because of the harsh environment of seafloor,high pressure and highly conductive seawater,marine magnetotelluric method developed slowly. The sea floor environment is similar to the environment of logging, According to the design of dual lateral logging equipment,a new equipment for seafloor electrical resistivity measurement is designed. Four 3D FEM models that contain resistivity abnormal targets are built to test the ability of this equipment to locate different shape of shallow buried resistivity abnormal targets in sea mud. The authors propose the method to correct the response curve while the bottom surface of this equipment is suspended or not parallel to the seafloor. The resistivity of targets can be calculated accurately.

Research on geo-electrical resistivity observation system specially used for earthquake monitoring in China

This paper deals with the design and development of the observational system of geo-electrical resistivity on the basis of the demands for exploring the temporal variations of electrical properties of Earth media in the fixed points of the networks, which would be associated with the earthquake preparation. The observation system is characterized by the high accuracy in measurement, long term stability in operation and high level of rejection to the environmental interference. It consists of three main parts, configuration system measurement system, the calibration and inspection system.

Application of geophysical methods in fine detection of urban concealed karst:A case study of Wuhan City,China

The construction of modern livable cities faces challenges in karst areas,including ground collapse and engineering problems.Wuhan,with a population of 13.74×10^(6) and approximately 1161 km^(2)of soluble rocks in the urban area of 8569.15 km^(2),predominantly consists of concealed karst areas where occasional ground collapse events occur,posing significant threats to underground engineering projects.To address these challenges,a comprehensive geological survey was conducted in Wuhan,focusing on major karstrelated issues.Geophysical methods offer advantages over drilling in detecting concealed karst areas due to their efficiency,non-destructiveness,and flexibility.This paper reviewed the karst geological characteristics in Wuhan and the geophysical exploration methods for karst,selected eight effective geophysical methods for field experimentation,evaluated their suitability,and proposed method combinations for different karst scenarios.The results show that different geophysical methods have varying applicability for karst detection in Wuhan,and combining multiple methods enhances detection effectiveness.The specific recommendations for method combinations provided in this study serve as a valuable reference for karst detection in Wuhan.

Relation between viscoplastic flow, periodic feature and Joule heat validity for electrically assisted friction stir welding

Electrically assisted friction stir welding is a promising way to improve liquidity of viscoplastic metal. However, this local heat source only can take into effect in a certain contact interface status. Semi-analytical model and FEM are adopted to analyze materials flow in electrically assisted FSW. Semi-analysis results show that Joule heating is validity with rotation speed 1 400 r/min and travel speed 400 mm/min. The maximum flow velocity is 0.033 m/s when travel speed is 400 mm/min, and it increases to 0.043 m/s with current assistant. Visco-plasticizing efficiency is a key factor to decide whether Joule heat is significant, and viscoplastic flow can periodically make circuit short. Periodic torque, axial force and onion rings surface show dynamic flow process, which can be used to illustrate the dynamic contact resistance feature and correct the calculation equation of Joule heat. This paper is aim to point out the potential relation between viscoplastic flow, periodic torque and Joule heating validity.

New “Intellectual Networks” (Smart Grid) for Detecting Electrical Equipment Faults, Defects and Weaknesses

The most important elements of “intellectual networks” (Smart Grid) are the systems of monitoring the parameters of electrical equipment. Information-measuring systems (IMS), which described in this paper, were proposed to use together with rapid digital protection against short-circuit regimes in transformer windings. This paper presents an application’s experience of LVI-testing, some results of the use of Frequency Response Analysis (FRA) to check the condition of transformer windings and infra-red control results of electrical equipment. The LVI method and short-circuit inductive reactance measurements are sensitive for detecting such faults as radial, axial winding deformations, a twisting of low-voltage or regulating winding, a losing of winding’s pressing and others.

基于电流监测和动态电阻分析的电容器组SF_(6)断路器电寿命评估系统

电容器组SF_(6)断路器电寿命状态监测工作对保障电网安全可靠运行意义重大。文中融合触头磨损计算方法和动态电阻分析法对SF_(6)断路器电寿命进行评估,提出SF_(6)断路器电寿命评估判据,首先基于断路器电流监测数据计算断路器触头磨损,对断路器电寿命状态进行判断预测,再利用动态电阻分析法印证判断出SF_(6)断路器的真实状态,兼顾触头磨损计算法的实时性和动态电阻法的准确性。基于所提判据,研发了一套融合触头磨损和动态电阻的SF_(6)断路器电寿命评估系统。该系统可基于断路器投切数据和动态电阻准确地评估SF_(6)断路器的电寿命,同时在人机交互界面上直观地呈现结果,为工作人员进行断路器状态检修提供辅助决策。

时移电阻率法三维反演研究

时移电阻率法是监测浅地表物性参数动态变化的有效方法之一.在实际应用中,由于观测噪声随时间变化,基于不同时刻观测数据单独反演所得的电性结构变化可能存在虚假信息.这些时变噪声引起的虚假信息增加了时移电阻率法解释的难度.本文通过在传统的正则化反演目标函数中增加时移约束来调控相邻时刻同一位置的电性差异,以抑制时变噪声产生的虚假变化.在此基础上,采用有限内存拟牛顿法实现了时移电阻率法三维反演.合成数据反演结果表明,相对于不同时刻监测数据单独反演的结果,时移反演可更好的抑制噪声影响,获取更准确的电性结构及其动态变化.野外实验数据反演结果表明,时移反演能更真实刻画实验区域的电性结构变化.上述结果表明,时移反演可以更好的压制由背景噪声引起的假异常,提高反演结果的准确性和解释的可靠性.本研究为时移电阻率法监测浅地表电性结构动态变化提供了一种有效途径.

自适应接地电阻的本安型电法监测场源信号发射装置设计

电法监测技术因其对煤岩电阻率变化的高灵敏特点而逐步在突水风险较高的矿井进行推广应用,然而由于井下工作面两巷工况环境复杂,不同场源发射监测电极间的接地条件差异较大且随时间变化,难以在整个监测周期内提供稳定的场源信号。设计了一种基于STM32F407的负反馈式本安型电法监测场源信号发射装置,该装置可自适应调节不同发射电极间的接入电阻,具备双重可靠本安保护电路,实现了本安限制条件下场源信号的最大功率稳定发射,既而使场源能量最大化加载至目标监测地质体来获得尽可能强的场源响应信号,提升电法监测系统数据采集质量,提高反演解释的准确性。

工作面顶板导水两带发育高度动态监测研究

随着我国煤矿开采深度、强度等的增加,采掘扰动极易诱发顶板水害事故。在矿井工作面回采过程中掌握煤层顶板导水两带发育规律,对煤层安全回采至关重要。文章以华北矿区某煤矿探查工作面顶板两带发育高度为目标,采用矿井并行电法动态监测技术,通过在顶板钻孔内布设监测电极,实时动态获取回采过程中煤层顶板覆岩地电场动态演化规律,推断得到该工作面监测区域导水裂隙带发育高度为61 m,垮落带发育高度为17.4 m,有效指导了现场矿井水害防治工作。

电力系统生产运行中电能质量监测与改进方法的研究

随着现代工业的快速发展,电能质量问题日益突出。电能质量的优劣直接影响着电力系统的安全、稳定运行及用户的经济效益。文章分析了影响电能质量的主要因素,探讨了电能质量监测的必要性和主要方法,并提出了切实可行的电能质量改善措施。文章的研究成果对于保障电力系统安全运行、提高供电质量具有重要的理论意义和实践价值。

Multi-parameter numerical simulation of dynamic monitoring of rock deformation in deep mining

The level of deformation development of surrounding rocks is a vital predictor to evaluate impending coal mine disasters and it is important to establish accurate measurements of the deformed status to ensure coal mine safety. Traditional deformation monitoring methods are mostly based on single parameter, in this paper, multiple approaches are integrated: firstly, both electric and elastic models are established,from which electric field distribution and seismic wave recording are calculated and finally, the resistivity profiles and source position information are determined using inversion methods, from which then the deformation and failure of mine floor are evaluated. According to the inversion results of both electric and seismic field signals, multiple-parameter dynamic monitoring of surrounding rock deformation in deep mine can be performed. The methodology is validated using numerical simulation results which shows that the multi-parameter dynamic monitoring methods have better results for surrounding rock deformation in deep mine monitoring than single parameter methods.

缆索桥梁拉索钢丝腐蚀测试方法

针对缆索桥梁腐蚀监测难的问题,以平行钢丝拉索镀锌高强钢丝为对象开展加速腐蚀试验,采用电阻法与传统称重法进行了腐蚀试件截面损失率对比测试,并分析了腐蚀物与温度对腐蚀电阻的影响,以此对电阻法进行钢丝腐蚀的监测和评估工程中应用的可行性进行论证。结果显示,电阻法与称重法测试具有相近的结果,在坑蚀时,两种测试法的偏差均值为3.8%,而在均匀腐蚀时的偏差均值仅为2.5%,两种腐蚀类型误差均较小,满足工程要求,因此,通过电阻法测试与评估拉索钢丝腐蚀率是可靠的。拉索钢丝温度和腐蚀物对腐蚀电阻的影响试验结果表明,腐蚀前后钢丝试件的温度系数与普通钢材接近,其值为0.00605,腐蚀物对腐蚀电阻的测试结果无明显影响,即在进行缆索桥梁拉索腐蚀监测时,腐蚀传感器的温度补偿及腐蚀量的计算时可不考虑腐蚀物的影响。

堆用SiC辐照温度监控器的研究进展

碳化硅(SiC)晶体可以用作无源监控器测量反应堆的中子辐照温度,在未来高温强辐射的先进核反应堆中具有重要的应用前景。SiC测温技术自20世纪60年代被首次提出以来,基于SiC结构、热学和电学性质的中子辐照效应,人们建立了宏观尺寸法、质量密度法、热导率法和电阻率法等各种SiC测温方法。本文首先综述了这些SiC测温方法的基本原理和工作特点,然后着重介绍了中国原子能科学研究院(China Institute of Atomic Energy,CIAE)SiC测温系统的研究进展,通过中子辐照诱导SiC晶格肿胀的理论计算,分析和验证了该系统测温结果的可靠性,探讨了进一步提高SiC测温效率的实验方法。

浅埋煤层地表动态变形规律实测研究

浅埋煤层高强度开采易诱发严重的开采沉陷灾害。为了分析浅埋煤层开采后地表沉陷特点,防治开采沉陷灾害,在马营煤矿9102综放工作面布置地表移动观测站,采用测回法,按照闭合测量路线进行动态变形监测,探讨了浅埋煤层地表移动动态特征。

工作面采动破坏过程电阻率动态响应特征研究

矿井电阻率法在采煤工作面水害隐患监测中发挥着重要作用,但工作面采动破坏过程的异常响应会对底板水害隐患的识别形成较大干扰。为了提高矿井电阻率法对采煤工作面底板水害隐患监测的解释精度,同步考虑覆岩破坏和底板破坏的影响,建立工作面采动破坏过程动态地电模型,通过矿井电阻率法三维数值模拟和反演成像,分别进行顶板监测和底板监测,分析采动破坏过程的电阻率动态响应特征,识别和提取底板水害隐患的电阻率响应特征。分析结果表明:采动破坏过程形成的电阻率异常区随回采工作面推进向前移动,在超前支撑压力的作用范围内会出现相对低阻异常,在采空区范围内会出现相对高阻异常;工作面固定位置的电阻率响应在回采过程中会经历先降低、后升高、再降低的过程,该过程与工作面回采过程中顶底板经历的周期性应力变化和破坏过程基本一致;底板水害隐患的低阻异常响应强度与其相对回采工作面的位置有关,当底板水害隐患的展布范围与采空区范围有所重合时,采空区的高阻异常响应会削弱底板水害隐患的低阻异常响应;当底板水害隐患的展布范围与超前支撑压力影响区范围有所重合时,二者的低阻异常响应会叠加在一起,使低阻异常响应得到一定幅度的增强;针对底板水害隐患进行纯异常提取后,可以消除采动破坏过程的影响,不同位置的底板水害隐患其纯异常响应强度基本一致,其垂向影响范围均大于采动破坏的垂向影响范围。

粗骨料对混凝土抗氯离子渗透性的影响研究

为研究粗骨料对混凝土抗氯离子渗透性能的影响,采用交流电测量法、RCM法和电通量法进行混凝土抗氯离子渗透试验。3种试验方法均表明氯离子的渗透阻力随粗骨料体积分数的增加而增加;当最大粗骨料粒径小于25 mm时氯离子渗透阻力随着粗骨料最大粒径的增加而增加,大于25 mm时氯离子渗透阻力随之降低。粗骨料最大粒径对边界效应层厚度的影响较小。

矿用高分辨电法监测系统设计

电阻率法是煤矿水害潜在风险判别、监测和预警的重要手段,也是矿井地质信息透明化的重要数据来源。进行井下电法监测时,单一的单巷电剖面法或双巷电透视法对富水区定位精度不高。此外,由于大规模电气设备产生的电磁干扰越来越强,传统的电法监测设备难以取得有效数据。针对上述问题,设计了一种矿用高分辨电法监测系统,该系统可在采动过程中实时进行单巷电剖面法及双巷电透视法数据的自动采集,并利用2种观测数据进行约束反演成像,提升了低阻异常体的成像分辨率。设计了二级放大及工频滤波电路,在进行电剖面和电透视数据采集时配置不同的采样时序、采样频率及数字滤波器,以抑制大规模电气设备对电法响应信号的干扰。性能测试结果表明,矿用高分辨电法监测系统可在噪声环境下有效分辨1μV目标信号,在电透视模式和电剖面模式下,工频抑制比分别不低于35 dB和80 dB。水槽物理模拟试验结果表明,该系统可有效分辨在工作面倾向约为300 m时底板下60 m处大小约为10 m3的低阻异常体。测试和试验结果验证了该系统具有较强的工频干扰和随机干扰抑制能力,能够在煤矿有限的观测空间和强干扰条件下获得可靠有效的数据,提高了反演结果中异常体的成像分辨率。

井间ERT电极阵列优化及监测实验系统设计与开发

为了开发用于地层中CO_(2)运移监测的井间ERT系统,研究了ERT电极阵列和工作模式优化设计方法并研制了井间ERT监测模拟实验系统;基于COMSOL平台构建了模拟井间ERT测量响应的有限元数值模型,利用数值模型分析了电极间距和宽度等参数对监测区域电场灵敏度的影响规律以及不同电极阵列工作模式下场域灵敏度的分布特征,确定了井间ERT实验系统中最优的电极参数,即电极间距、宽度与监测范围的比值分别为0.200、0.025,电极阵列的工作模式为AM-BN;在对实验系统进行功能需求分析、总体设计以及上述优化设计的基础上,分别对系统硬件部分和软件部分进行了开发,采用多路切换开关并配合精密电桥仪实现了对电阻抗参数的测量,利用以LabVIEW为平台开发的测控软件实现了对实验系统的自动化控制;以埋放绝缘物体来模拟注入地层CO_(2)的方式开展了实验测试,结果显示测量到的电阻抗数据可以灵敏地反映出监测区域电参数的变化且能够用于定位绝缘物体的位置,从而验证了所开发系统的可用性;所建立的电极阵列优化设计方法以及开发的井间ERT监测模拟实验系统为下一步深入研究基于复电导率参数的CO_(2)饱和度评价模型和开发现场适用的井间ERT监测系统提供了实验平台。

采用电阻率法的纵向弥散度室内测定研究

弥散度是表征地下水中污染物扩散的关键参数之一,对于模拟和预测污染物的扩散具有重要的意义。由于电阻率的测量具有简单快速的优势,本文采用电阻率法饱和砂体的弥散度值进行了评价。在室内进行一维水动力弥散实验,以氯化钠(NaCl)溶液作为示踪剂,采用电阻率法获得了不同位置的示踪剂穿透过程和去除过程,评价了石英砂的纵向弥散度值。结果显示:电阻率法能够得到示踪剂的扩散过程,评估的石英砂(60目)纵向弥散度值在0.166~0.225 cm范围内,平均值0.191 cm,与柱体出口测得的纵向弥散度0.233 cm相近。本研究表明电阻率法可以用于监测盐分等在多孔介质中的水动力弥散过程,并能对弥散度等关键参数进行评估。