Qifei Wang, Chengwu Li, Beijing Xie, Yuechao Zhao, Dihao Ai
The detection of electromagnetic radiation (EMR) during the fracture of solid materials such as rocks and coal has been widely used in seismic exploration and mine dynamic disaster prediction. As described in this paper, we conduct uniaxial compression tests on coal, cement, and glass materials to determine the characteristic EMR differences among materials. A band-stop filter based on the Fourier transform and the wavelet packet transform method are used to conduct signal denoising and analysis. Basic analyses of the pulse-time characteristics, energy distribution, cumulative energy, and waveform characteristics of EMR are conducted. The research results show that there is a strong corresponding relation between the loading time, loading stress and EMR energy. A large number of EMR events are released in rapid succession during the main rupture of coal and cement, while the EMR events are evenly distributed throughout the whole loading process of glass. For the same material, the maximum EMR amplitude increases with an increasing peak value of the stress. The EMR pulse waveform of coal and cement agrees well with predictions based on the theoretical formula of the electromagnetic dipole oscillation EMR generation mechanism. The paper provides further theoretical basis for understanding the mechanism of EMR, with great significance for improving coal mining safety.
{"title":"A Study on the Characteristics of Electromagnetic Radiation during Deformation and Failure of Different Materials Under Uniaxial Compression","authors":"Qifei Wang, Chengwu Li, Beijing Xie, Yuechao Zhao, Dihao Ai","doi":"10.2113/JEEG19-044","DOIUrl":"https://doi.org/10.2113/JEEG19-044","url":null,"abstract":"The detection of electromagnetic radiation (EMR) during the fracture of solid materials such as rocks and coal has been widely used in seismic exploration and mine dynamic disaster prediction. As described in this paper, we conduct uniaxial compression tests on coal, cement, and glass materials to determine the characteristic EMR differences among materials. A band-stop filter based on the Fourier transform and the wavelet packet transform method are used to conduct signal denoising and analysis. Basic analyses of the pulse-time characteristics, energy distribution, cumulative energy, and waveform characteristics of EMR are conducted. The research results show that there is a strong corresponding relation between the loading time, loading stress and EMR energy. A large number of EMR events are released in rapid succession during the main rupture of coal and cement, while the EMR events are evenly distributed throughout the whole loading process of glass. For the same material, the maximum EMR amplitude increases with an increasing peak value of the stress. The EMR pulse waveform of coal and cement agrees well with predictions based on the theoretical formula of the electromagnetic dipole oscillation EMR generation mechanism. The paper provides further theoretical basis for understanding the mechanism of EMR, with great significance for improving coal mining safety.","PeriodicalId":15748,"journal":{"name":"Journal of Environmental and Engineering Geophysics","volume":"59 1","pages":"139-152"},"PeriodicalIF":1.0,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89829912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nie Lichao, Ma Zhao, Bin Liu, Xu Zhenhao, Zhou Wei, Wang Chengkun, J. Shao, Yin Xin
There is a high demand for high detection accuracy and resolution with respect to anomalous bodies due to the increased development of underground spaces. This study focused on the weighted inversion of observed data from individual array type electrical resistivity tomography (ERT), and developed an improved method of applying a data weighing function to the geoelectrical inversion procedure. In this method, the weighting factor as an observed data weighting term was introduced into the objective function. For individual arrays, the sensitivity decreases with increasing electrode interval. Therefore, the Jacobian matrices were computed for the observed data of individual arrays to determine the value of the weighting factor, and the weighting factor was calculated automatically during inversion. In this work, 2D combined inversion of ERT data from four-electrode Alfa-type arrays is examined. The effectiveness of the weighted inversion method was demonstrated using various synthetic and real data examples. The results indicated that the inversion method based on observed data weighted function could improve the contribution of observed data with depth information to the objective function. It has been proven that the combined weighted inversion method could be a feasible tool for improving the accuracies of positioning and resolution while imaging deep anomalous bodies in the subsurface.
{"title":"A Weighting Function-Based Method for Resistivity Inversion in Subsurface Investigations","authors":"Nie Lichao, Ma Zhao, Bin Liu, Xu Zhenhao, Zhou Wei, Wang Chengkun, J. Shao, Yin Xin","doi":"10.2113/jeeg19-029","DOIUrl":"https://doi.org/10.2113/jeeg19-029","url":null,"abstract":"There is a high demand for high detection accuracy and resolution with respect to anomalous bodies due to the increased development of underground spaces. This study focused on the weighted inversion of observed data from individual array type electrical resistivity tomography (ERT), and developed an improved method of applying a data weighing function to the geoelectrical inversion procedure. In this method, the weighting factor as an observed data weighting term was introduced into the objective function. For individual arrays, the sensitivity decreases with increasing electrode interval. Therefore, the Jacobian matrices were computed for the observed data of individual arrays to determine the value of the weighting factor, and the weighting factor was calculated automatically during inversion. In this work, 2D combined inversion of ERT data from four-electrode Alfa-type arrays is examined. The effectiveness of the weighted inversion method was demonstrated using various synthetic and real data examples. The results indicated that the inversion method based on observed data weighted function could improve the contribution of observed data with depth information to the objective function. It has been proven that the combined weighted inversion method could be a feasible tool for improving the accuracies of positioning and resolution while imaging deep anomalous bodies in the subsurface.","PeriodicalId":15748,"journal":{"name":"Journal of Environmental and Engineering Geophysics","volume":"2677 1","pages":"129-138"},"PeriodicalIF":1.0,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90590633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
It has been found that the traditionally used electromagnetic wave instruments have limitations in detection depths, as well as a lack of directionality. Therefore, those types of instruments cannot meet the needs of geo-steering applications. However, azimuth electromagnetic wave instruments have shown the ability to quickly acquire effective geo-steering information using a tilt coil design method, which can potentially provide accurate guidance for decision-making in drilling direction adjustments. In this study, a design method for an azimuth electromagnetic wave detection instrument for underground coal mining was proposed. The relationships between the structural parameters of the instrument and installation angles of the coils and the response signals were obtained in this study using simulations. Then, by choosing reasonable instrument spacings, coil installation angles, and transmitting frequencies, the detection performances of the instrument were successfully improved. Also, the basic parameter selections of the proposed logging-while-drilling azimuth electromagnetic wave logging instrument were determined to be suitable for underground coal-mining purposes. It was also found that the symmetric compensation of the instrument was sensitive to the interface responses, and the anti-symmetric compensation was sensitive to the anisotropic responses. In addition, a method of detecting the interface positions and azimuth of coal-seam interfaces using azimuth electromagnetic waves, as well as the potential for the application of the instrument for the detection of low-resistivity anomalies in coal goafs, were effectively demonstrated. The results of this study provided theoretical references for future coal-seam boundary detections and explorations, and also added insight into the development processes of coal-seam bedding.
{"title":"Using an Azimuth Electromagnetic Wave Imaging Method to Detect and Characterize Coal-seam Interfaces and Low-resistivity Anomalies","authors":"Gang Chen, Yiren Fan, Quanxin Li","doi":"10.2113/JEEG19-041","DOIUrl":"https://doi.org/10.2113/JEEG19-041","url":null,"abstract":"It has been found that the traditionally used electromagnetic wave instruments have limitations in detection depths, as well as a lack of directionality. Therefore, those types of instruments cannot meet the needs of geo-steering applications. However, azimuth electromagnetic wave instruments have shown the ability to quickly acquire effective geo-steering information using a tilt coil design method, which can potentially provide accurate guidance for decision-making in drilling direction adjustments. In this study, a design method for an azimuth electromagnetic wave detection instrument for underground coal mining was proposed. The relationships between the structural parameters of the instrument and installation angles of the coils and the response signals were obtained in this study using simulations. Then, by choosing reasonable instrument spacings, coil installation angles, and transmitting frequencies, the detection performances of the instrument were successfully improved. Also, the basic parameter selections of the proposed logging-while-drilling azimuth electromagnetic wave logging instrument were determined to be suitable for underground coal-mining purposes. It was also found that the symmetric compensation of the instrument was sensitive to the interface responses, and the anti-symmetric compensation was sensitive to the anisotropic responses. In addition, a method of detecting the interface positions and azimuth of coal-seam interfaces using azimuth electromagnetic waves, as well as the potential for the application of the instrument for the detection of low-resistivity anomalies in coal goafs, were effectively demonstrated. The results of this study provided theoretical references for future coal-seam boundary detections and explorations, and also added insight into the development processes of coal-seam bedding.","PeriodicalId":15748,"journal":{"name":"Journal of Environmental and Engineering Geophysics","volume":"33 1","pages":"75-87"},"PeriodicalIF":1.0,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89298038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Magnetotelluric (MT) impedance and tipper data can be utilized to reflect underground structural information. However, when the axial anisotropic property of an abnormal body is marked, it will seriously influence MT measuring data. This study divides the MT field into primary and secondary components and replaces the conductivity parameter in a three-dimensional (3D) governing equation with axial anisotropic conductivity. Analysis of the influence of axial anisotropy on MT tipper data is presented, and a limited-memory Broyden-Fletcher-Goldfarb-Shanno method is then utilized to realize a 3D MT axial anisotropic inversion with impedance and tipper data. The tests presented in this paper show that the resolution of the inverting axial anisotropic model with impedance and tipper data is better than that of only using impedance data.
{"title":"Joint Inversion of Magnetotelluric Impedance and Tipper Data in 3D Axial Anisotropic Media","authors":"Wei Luo, Kunpeng Wang, Hui Cao, Changsheng Duan, Tao Wang, Xingxiang Jian","doi":"10.2113/JEEG19-022","DOIUrl":"https://doi.org/10.2113/JEEG19-022","url":null,"abstract":"Magnetotelluric (MT) impedance and tipper data can be utilized to reflect underground structural information. However, when the axial anisotropic property of an abnormal body is marked, it will seriously influence MT measuring data. This study divides the MT field into primary and secondary components and replaces the conductivity parameter in a three-dimensional (3D) governing equation with axial anisotropic conductivity. Analysis of the influence of axial anisotropy on MT tipper data is presented, and a limited-memory Broyden-Fletcher-Goldfarb-Shanno method is then utilized to realize a 3D MT axial anisotropic inversion with impedance and tipper data. The tests presented in this paper show that the resolution of the inverting axial anisotropic model with impedance and tipper data is better than that of only using impedance data.","PeriodicalId":15748,"journal":{"name":"Journal of Environmental and Engineering Geophysics","volume":"354 1","pages":"25-36"},"PeriodicalIF":1.0,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82609810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The electromagnetic-wave attenuation coefficient determines the overall resolution and effective penetration depth of ground penetrating radar (GPR) surveys. Despite this relevance to the design of proper GPR surveys, the attenuation expressions are rarely used in the applied shallow groundwater research (SGR) literature. This work examines the status of the attenuation expressions in SGR. For this, 73 GPR case studies (in 47 papers), including some information concerning the attenuation variables and parameters, were selected to build a database. From these, 18 cases (in 10 papers) provided attenuation expressions and only 11 cases (in 4 papers) used those expressions. Two types of expressions were identified, physically based global ones that try to solve a broad (but not complete) range of environmental and field technical conditions, and non-global ones adapted for specific geological environments and resolution needed. The database analysis showed that both global and non-global expressions were used exclusively in low-loss media to report an attenuation range of 0.1–21.5 dB m−1 by using common antenna frequencies in the 25–900 MHz range. The range of the attenuation expressions validity in SGR is biased because no surveys in variable-loss heterogeneous media and wider antenna frequency intervals could be compiled. The attenuation database generated seeks to improve the design of GPR surveys in SGR.
电磁波衰减系数决定了探地雷达探测的总分辨率和有效探深。尽管衰减表达式与合理的探地雷达测量设计相关，但在应用浅层地下水研究(SGR)文献中很少使用衰减表达式。本文研究了SGR中衰减表达式的现状。为此，选取了73个GPR案例研究(47篇论文)，包括一些有关衰减变量和参数的信息，建立数据库。其中，18例(10篇论文)提供了衰减表达式，只有11例(4篇论文)使用了衰减表达式。确定了两种类型的表达，一种是基于物理的全球表达，试图解决广泛(但不完整)的环境和现场技术条件，另一种是非全球表达，适用于特定的地质环境和所需的分辨率。数据库分析表明，使用25-900 MHz范围内的公共天线频率，在低损耗介质中只使用全局和非全局表达式，报告的衰减范围为0.1-21.5 dB m−1。由于无法编制变损耗非均匀介质和较宽天线频率间隔的调查，SGR中衰减表达式的有效性范围存在偏差。生成的衰减数据库旨在改进SGR中探地雷达调查的设计。
{"title":"Ground Penetrating Radar Attenuation Expressions in Shallow Groundwater Research","authors":"M. C. Paz, F. Alcalá, L. Ribeiro","doi":"10.2113/JEEG19-039","DOIUrl":"https://doi.org/10.2113/JEEG19-039","url":null,"abstract":"The electromagnetic-wave attenuation coefficient determines the overall resolution and effective penetration depth of ground penetrating radar (GPR) surveys. Despite this relevance to the design of proper GPR surveys, the attenuation expressions are rarely used in the applied shallow groundwater research (SGR) literature. This work examines the status of the attenuation expressions in SGR. For this, 73 GPR case studies (in 47 papers), including some information concerning the attenuation variables and parameters, were selected to build a database. From these, 18 cases (in 10 papers) provided attenuation expressions and only 11 cases (in 4 papers) used those expressions. Two types of expressions were identified, physically based global ones that try to solve a broad (but not complete) range of environmental and field technical conditions, and non-global ones adapted for specific geological environments and resolution needed. The database analysis showed that both global and non-global expressions were used exclusively in low-loss media to report an attenuation range of 0.1–21.5 dB m−1 by using common antenna frequencies in the 25–900 MHz range. The range of the attenuation expressions validity in SGR is biased because no surveys in variable-loss heterogeneous media and wider antenna frequency intervals could be compiled. The attenuation database generated seeks to improve the design of GPR surveys in SGR.","PeriodicalId":15748,"journal":{"name":"Journal of Environmental and Engineering Geophysics","volume":"25 1","pages":"153-160"},"PeriodicalIF":1.0,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87688143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Based on surface magnetic resonance sounding (MRS), a relationship is proposed to express the MRS response signal with a vertical coil for the MRS method for a whole underground space model. Firstly, the declination and inclination characteristics of the Earth's magnetic field and the coil normal angle are studied by deriving the angle rotation matrix. Surprisingly, the results indicate that the MRS signal can be effectively improved by changing the normal direction of the coil perpendicular to that of the Earth's magnetic field. The advanced detection distance of the underground MRS method is closely related to the exciting pulse moment and the receiving sensitivity. Hence, a larger pulse moment and high receiving sensitivity correspond to a longer advanced detection distance. However, the limited transmitting moment will reduce the advanced detection distance. In the research coincident loop with the coil 2 m by 2 m square is employed. In order to overcome the noises with 1 nV and 100 nV level, the turns of loop should be 100 turns and 400 turns, respectively. Finally, the numerical simulation results verify the feasibility of underground whole MRS theory and resolution analysis method for the advanced detection of water-inrush disasters in mines and tunnels.
{"title":"A Theoretical Study of Underground Magnetic Resonance Sounding for the Advanced Detection of Water Influxes in Tunnels","authors":"Yue Zhao, Jun Lin, Chuandong Jiang, Xiaofeng Yi","doi":"10.2113/JEEG19-021","DOIUrl":"https://doi.org/10.2113/JEEG19-021","url":null,"abstract":"Based on surface magnetic resonance sounding (MRS), a relationship is proposed to express the MRS response signal with a vertical coil for the MRS method for a whole underground space model. Firstly, the declination and inclination characteristics of the Earth's magnetic field and the coil normal angle are studied by deriving the angle rotation matrix. Surprisingly, the results indicate that the MRS signal can be effectively improved by changing the normal direction of the coil perpendicular to that of the Earth's magnetic field. The advanced detection distance of the underground MRS method is closely related to the exciting pulse moment and the receiving sensitivity. Hence, a larger pulse moment and high receiving sensitivity correspond to a longer advanced detection distance. However, the limited transmitting moment will reduce the advanced detection distance. In the research coincident loop with the coil 2 m by 2 m square is employed. In order to overcome the noises with 1 nV and 100 nV level, the turns of loop should be 100 turns and 400 turns, respectively. Finally, the numerical simulation results verify the feasibility of underground whole MRS theory and resolution analysis method for the advanced detection of water-inrush disasters in mines and tunnels.","PeriodicalId":15748,"journal":{"name":"Journal of Environmental and Engineering Geophysics","volume":"25 1","pages":"37-46"},"PeriodicalIF":1.0,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81127730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ruyun Tian, Ma Liwei, Xiaohua Zhou, Wang Junqiu, Jun Lin, Dong-sheng Li
The soil-rock mixture sedimentary stratum is a compound with complex and loose topography, of which the structure is difficult to detect by the ordinary geophysical method. There is a need for a convenient, efficient and effective geophysical method to detect site effects in this area. This paper is an application of the S wave velocity profile inversion for the soil-rock mixture sedimentary stratum, using HVSR (Horizontal to Vertical Spectral Ratio) analysis of ambient noise by some three-component observations in the Chinese Loess Plateau. We carried out the measurement using three nested circular arrays and data recording systems with a spectrum expansion circuit. Inversion of the HVSR curves was performed by a three-layer model. Results of geological observation reveal that the upper part of the sedimentary stratum is Quaternary strata containing a large amount of humus and loess, the middle layer part is the stratum of the loose gravel and the under part is completely weathered granite with homogeneous lithology and fewer rocks. Interpretation results are consistent with previous drilling data, providing a valid geophysical basis for evaluating the stability of the soil erosion and designing a reasonable water and soil erosion control scheme.
{"title":"Site Characterization of Soil-rock Mixture Sedimentary Stratum Based on HVSR Analysis in the Chinese Loess Plateau","authors":"Ruyun Tian, Ma Liwei, Xiaohua Zhou, Wang Junqiu, Jun Lin, Dong-sheng Li","doi":"10.2113/JEEG19-060","DOIUrl":"https://doi.org/10.2113/JEEG19-060","url":null,"abstract":"The soil-rock mixture sedimentary stratum is a compound with complex and loose topography, of which the structure is difficult to detect by the ordinary geophysical method. There is a need for a convenient, efficient and effective geophysical method to detect site effects in this area. This paper is an application of the S wave velocity profile inversion for the soil-rock mixture sedimentary stratum, using HVSR (Horizontal to Vertical Spectral Ratio) analysis of ambient noise by some three-component observations in the Chinese Loess Plateau. We carried out the measurement using three nested circular arrays and data recording systems with a spectrum expansion circuit. Inversion of the HVSR curves was performed by a three-layer model. Results of geological observation reveal that the upper part of the sedimentary stratum is Quaternary strata containing a large amount of humus and loess, the middle layer part is the stratum of the loose gravel and the under part is completely weathered granite with homogeneous lithology and fewer rocks. Interpretation results are consistent with previous drilling data, providing a valid geophysical basis for evaluating the stability of the soil erosion and designing a reasonable water and soil erosion control scheme.","PeriodicalId":15748,"journal":{"name":"Journal of Environmental and Engineering Geophysics","volume":"13 1","pages":"101-109"},"PeriodicalIF":1.0,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79224115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chuan Li, Jianxin Liu, Jianping Liao, Jianping Liao, A. Hursthouse
This paper presents a method for combining the hybrid eikonal solver and the prior velocity information to obtain high-resolution crosswell imaging. The hybrid eikonal solver in this technique can ensure rapid and reliable forward modeling of traveltime field in an unsmoothed velocity model. We also utilize the sonic well logging curve to properly develop an initial reference velocity model, and use the sonic well logging data as the prior information for the inversion part, which can restrict the problem of non-uniqueness. The results of the numerical experiment of traveltime in multi-layer media showed that the hybrid eikonal solver was more accurate than the finite difference method. The case study of an oil field in eastern China demonstrated that our method can derive a high-resolution reconstruction of the subsurface structure by inverting the primary traveltime datasets. These results suggest that even though the eikonal equation is a high frequency approximation to the wavefield, the hybrid eikonal solver can provide an accurate traveltime field in the forward modelling step of seismic crosswell tomography, which is critical to ensure high-resolution invert imaging in a highly heterogeneous environment.
{"title":"2D High-Resolution Crosswell Seismic Traveltime Tomography","authors":"Chuan Li, Jianxin Liu, Jianping Liao, Jianping Liao, A. Hursthouse","doi":"10.2113/JEEG19-003","DOIUrl":"https://doi.org/10.2113/JEEG19-003","url":null,"abstract":"This paper presents a method for combining the hybrid eikonal solver and the prior velocity information to obtain high-resolution crosswell imaging. The hybrid eikonal solver in this technique can ensure rapid and reliable forward modeling of traveltime field in an unsmoothed velocity model. We also utilize the sonic well logging curve to properly develop an initial reference velocity model, and use the sonic well logging data as the prior information for the inversion part, which can restrict the problem of non-uniqueness. The results of the numerical experiment of traveltime in multi-layer media showed that the hybrid eikonal solver was more accurate than the finite difference method. The case study of an oil field in eastern China demonstrated that our method can derive a high-resolution reconstruction of the subsurface structure by inverting the primary traveltime datasets. These results suggest that even though the eikonal equation is a high frequency approximation to the wavefield, the hybrid eikonal solver can provide an accurate traveltime field in the forward modelling step of seismic crosswell tomography, which is critical to ensure high-resolution invert imaging in a highly heterogeneous environment.","PeriodicalId":15748,"journal":{"name":"Journal of Environmental and Engineering Geophysics","volume":"31 1","pages":"47-53"},"PeriodicalIF":1.0,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84146791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Introduction to the JEEG Special Issue on Geophysics for Urban Underground Space Studies","authors":"Lanbo Liu, R. Qian","doi":"10.2113/JEEG24.4.V","DOIUrl":"https://doi.org/10.2113/JEEG24.4.V","url":null,"abstract":"","PeriodicalId":15748,"journal":{"name":"Journal of Environmental and Engineering Geophysics","volume":"86 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2019-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74691031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nie Lichao, Ma Zhao, Wang Chengkun, Rentai Liu, Liu Zhengyu, Zhou Wei, Jian Li, S. Ju
Metros are mass rapid-transit systems that have helped solve commuting problems for residents of metropolises throughout the world. However, adverse geological structures, leading to problem such as water inrush and mud gushing, pose a major threat to metro construction. Geophysical survey techniques provide quick and relatively inexpensive ways to detect adverse geological structures ahead of the tunnel face. Left line of the R3 metro tunnel in Qingdao, China will pass an aquifer sand layer under the Wolong River. To map the geological conditions below the river, we proposed a comprehensive prospecting method that would combine the merits of surface electrical resistivity imaging (S-ERT), seismic ahead prospecting, and tunnel-face and borehole electrical resistivity imaging (TBERI). The prospecting scheme was effectively revealed in a numerical model analysis, in which the stratum distribution was reconstructed using S-ERT. Field tests validated the synthetic results. The ahead prospecting scheme was able to reconstruct the distribution of an aquifer sand layer. Based on the results obtained, we believe that, the proposed scheme could play an important role in metro tunnel construction.
{"title":"Integrated ERT, Seismic, and Electrical Resistivity Imaging for Geological Prospecting on Metro Line R3 in Qingdao, China","authors":"Nie Lichao, Ma Zhao, Wang Chengkun, Rentai Liu, Liu Zhengyu, Zhou Wei, Jian Li, S. Ju","doi":"10.2113/JEEG24.04.537","DOIUrl":"https://doi.org/10.2113/JEEG24.04.537","url":null,"abstract":"Metros are mass rapid-transit systems that have helped solve commuting problems for residents of metropolises throughout the world. However, adverse geological structures, leading to problem such as water inrush and mud gushing, pose a major threat to metro construction. Geophysical survey techniques provide quick and relatively inexpensive ways to detect adverse geological structures ahead of the tunnel face. Left line of the R3 metro tunnel in Qingdao, China will pass an aquifer sand layer under the Wolong River. To map the geological conditions below the river, we proposed a comprehensive prospecting method that would combine the merits of surface electrical resistivity imaging (S-ERT), seismic ahead prospecting, and tunnel-face and borehole electrical resistivity imaging (TBERI). The prospecting scheme was effectively revealed in a numerical model analysis, in which the stratum distribution was reconstructed using S-ERT. Field tests validated the synthetic results. The ahead prospecting scheme was able to reconstruct the distribution of an aquifer sand layer. Based on the results obtained, we believe that, the proposed scheme could play an important role in metro tunnel construction.","PeriodicalId":15748,"journal":{"name":"Journal of Environmental and Engineering Geophysics","volume":"87 1","pages":"537-547"},"PeriodicalIF":1.0,"publicationDate":"2019-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90838451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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