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4th GeoShanghai International Conference on Rock Mechanics and Rock Engineering

作者： Zhu, Quanjie Liu, Jinhai Gao, Linsheng Chen, Zhihua Liu, Xiaohui North China Inst Sci & Technol Sch Safety Engn Beijing 101601 Peoples R China North China Inst Sci & Technol Hebei State Key Lab Mine Disaster Prevent Beijing 101601 Peoples R China Henan Normal Univ Sch Environm Xinxiang 453007 Peoples R China

ISBN: (纸本)9789811301131;9789811301124

Geostress is the basis for mining and geotechnical engineering designs, and dynamic disaster preventions. And the geostress inversion is a mathematical procedure that to calculate and extend the geostress field distribution base on a handful of measurement results. In order to make use of fine distribution characteristics of geostress field to evaluate the rock burst risk in a target area, this study carried out corresponding research contents for a deep mine in Shandong Province: (1) Conducted site measurements of geostress by means of hollow inclusion method;(2) Developed a complex 3D geological model based on multi-software to inverse and reconstruct the complex geostress fields coupled with multiple linear regression (MLR);(3) Compared the microseismic monitoring results with 3D geological model nephogram and provide theoretical basis for rock burst risk evaluation and regionalization in target area. Results showed that the reconstitution of 3D geological model gave well agreement with experimental results. The geostress evaluated results of 3D model of were consistent with the actual rock burst risk situation. The rapid constructed 3D geological model construction was expected to provide a certain reference meanings for geostress analysis to similar mines.

关键词： In-situ stress modeling and inversion Hollow inclusion Microseismic Evaluation

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Propeller sheet cavitation noise source modeling and inversion

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JOURNAL OF SOUND AND VIBRATION 2014年第5期333卷 1356-1368页

作者： Lee, Keunhwa Lee, Jaehyuk Kim, Dongho Kim, Kyungseop Seong, Woojae Seoul Natl Univ Res Inst Marine Syst Engn Seoul 151742 South Korea Seoul Natl Univ Dept Ocean Engn Seoul 151742 South Korea Agcy Def Dev Chang Won 645600 Gyeongnam South Korea

Propeller sheet cavitation is the main contributor to high level of noise and vibration in the after body of a ship. Full measurement of the cavitation-induced hull pressure over the entire surface of the affected area is desired but not practical. Therefore, using a few measurements on the outer hull above the propeller in a cavitation tunnel, empirical or semi-empirical techniques based on physical model have been used to predict the hullinduced pressure (or hull-induced force). In this paper, with the analytic source model for sheet cavitation, a multi-parameter inversion scheme to find the positions of noise sources and their strengths is suggested. The inversion is posed as a nonlinear optimization problem, which is solved by the optimization algorithm based on the adaptive simplex simulated annealing algorithm. Then, the resulting hull pressure can be modeled with boundary element method from the inverted cavitation noise sources. The suggested approach is applied to the hull pressure data measured in a cavitation tunnel of the Samsung Heavy Industry. Two monopole sources are adequate to model the propeller sheet cavitation noise. The inverted source information is reasonable with the cavitation dynamics of the propeller and the modeled hull pressure shows good agreement with cavitation tunnel experimental data. (C) 2013 Elsevier Ltd. All rights reserved.

关键词： Propeller sheet cavitation noise source modeling and inversion PROPELLER inversion datum pressure sheet cavitation cavitation tunnel Affected Area Noise levels Noise sources Optimization algorithms Hull

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Comparison of the 2-D and Quasi-3-D Geoelectric Models of the Ukrainian Eastern Carpathians and Their Link to the Tectonic Structure

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TECTONICS 2019年第11期38卷 3818-3834页

作者： Kovacikova, Svetlana Logvinov, Igor Tarasov, Viktor Acad Sci Inst Geophys Prague Czech Republic Nation Acad Sci Ukraine Subbotin Inst Geophys Kiev Ukraine

We present results of a study of the electrical conductivity distribution beneath the Ukrainian Eastern Carpathians where the Carpathian arc turns to the southeast and reaches the maximum curvature further in the Romanian territory. We have used the magnetotelluric and magnetovariational data in the period range of 1-6,000 s collected by geoelectric groups from several countries during deep induction experiments, which covered the studied area by a number of field stations clustered along profiles crossing the Carpathian arc. In this work, we compare the 2-D and quasi-3-D thin sheet inverse models, which allow us to constrain both the geometry and electrical properties of the anomalous conductivity structures beneath the Carpathians. Comparison of the inverse results with the Carpathians tectonics indicates that the Carpathian conductivity anomaly within the Polish and Slovak territory is located approximately between the Magura nappe front and the Pieniny Klippen Belt. In Ukraine, where the Magura nappe narrows and disappears, the anomaly reaches the front of the Outer Carpathians. The resulting quasi-3-D model of the conductivity structure beneath the Carpathians is compared with other geophysical and geological data within the region. The relation of the position of the conductors to the heat flow models and to location of the earthquakes sources indicates possible geological mechanisms, such as saline pore fluids, thin films of grain boundary graphite, or partial melting, connected with recent activation zones.

关键词： Electrical conductivity magnetotellurics modeling and inversion Ukrainian Eastern Carpathians

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A discussion of 2D induced polarization effects in airborne electromagnetic and inversion with a robust 1D laterally constrained inversion scheme

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GEOPHYSICS 2019年第2期84卷 E75-E88页

作者： Lin, Changhong Fiandaca, Gianluca Auken, Esben Couto, Marco Antonio Christiansen, Anders Vest China Univ Geosci Beijing Sch Geophys & Informat Technol Beijing Peoples R China Aarhus Univ Dept Geosci Hydrogeophys Grp Aarhus Denmark CPRM Geol Survey Brazil Sao Paulo Brazil

Recently, the interest in the induced polarization (IP) phenomenon in airborne time-domain electromagnetic (ATEM) data has increased considerably. IP may affect the ATEM data significantly and mask underlying geologic structures. To simulate 2D airborne IP data, a 2D finite-element forward-modeling algorithm has been developed with the dispersive conductivity described by the well-known Cole-Cole model. We verify our algorithm by comparison with the 1D solution of the Aarhuslnv code. Two-dimensional forward responses on six synthetic models, mimicking archetypal 2D conductive and chargeable anomalies, have been generated, and the results indicate that 2D IP affects the data significantly. Differences between the 2D IP responses and the 1D IP responses are evident above the 2D anomalies and at their edges. These differences are similar to what is found when comparing 2D and 1D forward responses over conductive 2D anomalies without considering IP. We evaluate an effective robust inversion scheme to recover the 2D IP parameters using the 1D laterally constrained inversion (LCI) scheme. The inversion of the synthetic data using the robust scheme indicates that not only can the IP parameters be recovered, but also the IP inversions can provide more accurate resistivity sections than a resistivity-only inversion, in terms of resistivity values and anomaly thickness/depth. The field example from Hope Bay area in Canada is even more valuable, considering that part of the profile consists of only negative data, which cannot be inverted with a resistivity-only scheme. Furthermore, the edge effects at the anomaly boundaries are less pronounced in the IP parameters than in the resistivity parameter on the synthetic models with more conductive backgrounds.

关键词： induced polarization 2D effects modeling and inversion airborne time-domain electromagnetic

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Geophysical investigation of tumuli by means of surface 3D Electrical Resistivity Tomography

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JOURNAL OF APPLIED GEOPHYSICS 2010年第3期70卷 192-205页

作者： Papadopoulos, Nikos G. Yi, Myeong-Jong Kim, Jung-Ho Tsourlos, Panagiotis Tsokas, Gregory N. Korea Inst Geosci & Mineral Resources Mineral Resources Res Div Explorat Geophys & Min Engn Dept Taejon 305350 South Korea Aristotle Univ Thessaloniki Dept Geophys Sch Geol Thessaloniki 54124 Greece

Tumuli are artificially erected small hills that cover monumental tombs or graves. In this work, the surface three-dimensional (3D) Electrical Resistivity Tomography (ERT) method, composed of dense parallel two-dimensional (2D) tomographies, was used to investigate the properties of the tumuli filling material and to resolve buried archaeological structures inside the tumuli. The effectiveness of the method was investigated by numerical modeling and through 3D inversion of synthetic apparent resistivity data. A resistivity model that simulates the inhomogeneous tumulus material and the tombs that are buried inside the tumulus was assumed. The Dipole-Dipole (DD), Pole-Dipole (PD), Pole-Pole (PP), Gradient (GRAD). Midpoint-Potential-Referred (MPR) and Schlumberger Reciprocal (SCR) arrays, which are suitable for multichannel resistivity instruments, were tested. The tumulus topography (pyramid or capsized cup) was incorporated into the inversion procedure through a distorted finite element mesh. The inversion procedure was based on a smoothness constrained Gauss-Newton algorithm in which the Active Constraint Balancing (ACB) method was also applied in order to enhance the least-squares resolving power and stability. Synthetic modeling showed that the different tumulus layers and the horizontal contact of the artificial tumulus material with the natural background soil were reconstructed by all of the tested electrode arrays. Generally, PD and the GRAD arrays comprise the optimum choices to investigate the subsurface properties of a tumulus and locate buried tombs. The MPR model was inferior to the GRAD model, while the DD, PP and SCR models had the poorest resolution. It was also shown that the inversion models are practically independent from the survey direction and the topography shape of the tumulus. The real field data collected employing the PD array along a small tumulus from the archaeological site of Vergina in northern Greece enhanced the synthetic modeling r

关键词： Tumulus 3D ERT modeling and inversion Vergina archaeological site

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Microseismic monitoring of borehole fluid injections: Data modeling and inversion for hydraulic properties of rocks

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GEOPHYSICS 2003年第2期68卷 685-689页

作者： Rothert, E Shapiro, SA Free Univ Berlin Fachrichtung Geophys D-12249 Berlin Germany

Attention paid to microseismic monitoring during geother- mal or hydrocarbon reservoir operations has grown consider- ably over the last several years. The observation of microseis- micity occurring during borehole uid injections or extractions has a large potential in characterizing reservoirs at locations as far as several kilometers from boreholes (Talwani and Acree, 1985; Adushkin et al., 2000; Fehler et al., 2001). The most common application has been hydraulic fracture imaging and growth characterization (e.g., Phillips et al., 1997; Urbancic et al., 1999). Longer-term microseismic monitoring has been used to map oil-producing natural fractures (e.g., Rutledge et al., 1998); it also shows promise in tracking ood fronts in the case of enhanced oil recovery (e.g., Maxwell et al., 1998). Be- yond delineating conductive fracture geometry and inferring uid-ow paths, microseismic data could potentially be used to measurein-situhydraulicpropertiesofrocksatinterwellscales, providing information that could further guide operations to optimize eld production.

关键词： .reconstruct spatio-temporal hydraulic properties microseismicity hydraulic diffusivity SBRC modeling and inversion borehole fluid injections microseismic data

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Correction of seafloor magnetotelluric data for topographic effects during inversion

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JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH 2005年第B12期110卷 1-16页

作者： Baba, K Chave, AD Japan Agcy Marine Earth Sci & Technol Inst Res Earth Evolut Yokosuka Kanagawa Japan Woods Hole Oceanog Inst Dept Appl Ocean Phys & Engn Woods Hole MA 02543 USA

[1] The large contrast in electrical conductivity between seawater and the underlying seafloor accumulates boundary electric charges which can severely distort observed electric and magnetic fields. For marine magnetotelluric (MT) studies, correcting this topographic effect is critical to obtaining accurate conductivity models for the mantle. Previously, correction for topography was based on the thin sheet approximation which breaks down at periods under similar to 1000 s in the deep ocean. This paper introduces an analysis method for seafloor MT data which combines removal of three-dimensional (3-D) topographic effects with inversion of the data for 2-D structure. The observed MT impedance is first corrected to a flat-lying seafloor datum using the observed bathymetry without invoking the thin sheet approximation. The corrected MT response is then inverted in a flat seafloor model space. Because of coupling between topographic effects and deeper structure, the correction and inversion steps are iterated until changes in each become small. The procedure is verified using synthetic and real data. Tests for synthetic 3-D topography over a half-space show that the method closely recovers the true half-space model after a few iterations. The procedure is also applied to real data collected in the Mantle Electromagnetic and Tomography ( MELT) experiment on the East Pacific Rise at 17 degrees S.

关键词： marine magnetotellurics topographic correction modeling and inversion

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New parallel stochastic global integral and local differential equation modeling and inversion

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PHYSICA D 1999年第1-4期133卷 477-487页

作者： Xie, GQ Li, JH Univ Calif Berkeley Lawrence Berkeley Lab Div Earth Sci Berkeley CA 94720 USA

In this paper, a new parallel modeling and inversion algorithm using a Stochastic Global Integral and Local Differential equation (SGILD) decomposition is presented. We derived new acoustic integral equations and differential equations for statistical moments of the parameters and field. The:new statistical moment integral equations on the boundary and local differential equations in domain will be used together to obtain mean wave field and its moments in the modeling. The new moment global Jacobian volume integral equations and the local Jacobian differential equations in domain will be used together to update the mean parameters and their moments in the inversion. A new parallel multiple hierarchy substructure direct algorithm or direct-iteration hybrid algorithm will be used to solve the sparse matrices and one smaller full matrix from domain to the boundary, in parallel. The SGILD modeling and imaging algorithm has many advantages over the conventional imaging approaches. The SGILD algorithm can be used for the stochastic acoustic, electromagnetic, and flow modeling and inversion. (C) 1999 Elsevier Science B.V. All rights reserved.

关键词： SGILD stochastic modeling and inversion moments integral and differential equation posterior probability optimization

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3-D RESISTIVITY FORWARD modeling and inversion USING CONJUGATE GRADIENTS

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GEOPHYSICS 1995年第5期60卷 1313-1325页

作者： ZHANG, J MACKIE, RL MADDEN, TR Earth Resources Laboratory Dept. of Earth Atmospheric and Planetary Sciences Massachusetts Institute of Technology

We have developed rapid 3-D dc resistivity forward modeling and inversion algorithms that use conjugate gradient relaxation techniques. In the forward network modeling calculation, an incomplete Cholesky decomposition for preconditioning and sparse matrix routines combine to produce a fast and efficient algorithm (approximately 2 minutes CPU time on a Sun SPARC-station 2 for 50 x 50 x 20 blocks). The side and bottom boundary conditions are scaled impedance conditions that take into account the local current flow at the boundaries as a result of any configuration of current sources. For the inversion, conjugate gradient relaxation is used to solve the maximum likelihood inverse equations, Since conjugate gradient techniques only require the results of the sensitivity matrix ($) under tilde A or its transpose ($) under tilde A(T) multiplying a vector, we are able to bypass the actual computation of the sensitivity matrix and the inversion of ($) under tilde A(T) ($) under tilde A, thus greatly decreasing the time needed to do 3-D inversions. We demonstrate 3-D resistivity tomographic imaging using pole-pole resistivity data collected during an experiment for a leakage monitoring system near evaporation ponds at the Mojave Generating Station in Laughlin, Nevada.

关键词： .sensitivity RELAXATION equations solve gradients algorithm incomplete maximum likelihood modeling and inversion using conjugate conjugate gradient Cholesky pole-pole

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