To speed up three-dimensional （3D） DC resistivity modeling, we present a new multigrid method, the aggregation-based algebraic multigrid method （AGMG）. We first discretize the differential equation of the secondar...To speed up three-dimensional （3D） DC resistivity modeling, we present a new multigrid method, the aggregation-based algebraic multigrid method （AGMG）. We first discretize the differential equation of the secondary potential field with mixed boundary conditions by using a seven-point finite-difference method to obtain a large sparse system of linear equations. Then, we introduce the theory behind the pairwise aggregation algorithms for AGMG and use the conjugate-gradient method with the V-cycle AGMG preconditioner （AGMG-CG） to solve the linear equations. We use typical geoelectrical models to test the proposed AGMG-CG method and compare the results with analytical solutions and the 3DDCXH algorithm for 3D DC modeling （3DDCXH）. In addition, we apply the AGMG-CG method to different grid sizes and geoelectrical models and compare it to different iterative methods, such as ILU-BICGSTAB, ILU-GCR, and SSOR-CG. The AGMG-CG method yields nearly linearly decreasing errors, whereas the number of iterations increases slowly with increasing grid size. The AGMG-CG method is precise and converges fast, and thus can improve the computational efficiency in forward modeling of three-dimensional DC resistivity.展开更多
为了确定煤与瓦斯突出矿井巷道掘进过程中的突出检验指标——突出预测敏感指标及临界值,指导现场防突措施的效果,对实验室相关参数进行分析并收集整理历史资料,筛选确定工作面突出危险性预测敏感指标及其临界值初始值,最后采用三率法和...为了确定煤与瓦斯突出矿井巷道掘进过程中的突出检验指标——突出预测敏感指标及临界值,指导现场防突措施的效果,对实验室相关参数进行分析并收集整理历史资料,筛选确定工作面突出危险性预测敏感指标及其临界值初始值,最后采用三率法和灰色关联法,确定突出煤层工作面突出危险性预测敏感指标临界值。根据乌兰煤矿掘进巷道的现场考察情况,确定了7#煤层突出危险性预测敏感指标为钻屑瓦斯解吸指标k1值及钻屑量指标S值,其临界值在正常地质条件下k1值为0.48 m L/(g·min0.5)、钻屑量S值为4.82 kg/m;在异常地质条件下k1值为0.38 m L/(g·min0.5)、钻屑量S值为3.85 kg/m。展开更多
基金supported by the Natural Science Foundation of China(Nos.41404057,41674077 and 411640034)the Nuclear Energy Development Project of China,and the‘555’Project of Gan Po Excellent People
文摘To speed up three-dimensional （3D） DC resistivity modeling, we present a new multigrid method, the aggregation-based algebraic multigrid method （AGMG）. We first discretize the differential equation of the secondary potential field with mixed boundary conditions by using a seven-point finite-difference method to obtain a large sparse system of linear equations. Then, we introduce the theory behind the pairwise aggregation algorithms for AGMG and use the conjugate-gradient method with the V-cycle AGMG preconditioner （AGMG-CG） to solve the linear equations. We use typical geoelectrical models to test the proposed AGMG-CG method and compare the results with analytical solutions and the 3DDCXH algorithm for 3D DC modeling （3DDCXH）. In addition, we apply the AGMG-CG method to different grid sizes and geoelectrical models and compare it to different iterative methods, such as ILU-BICGSTAB, ILU-GCR, and SSOR-CG. The AGMG-CG method yields nearly linearly decreasing errors, whereas the number of iterations increases slowly with increasing grid size. The AGMG-CG method is precise and converges fast, and thus can improve the computational efficiency in forward modeling of three-dimensional DC resistivity.
文摘为了确定煤与瓦斯突出矿井巷道掘进过程中的突出检验指标——突出预测敏感指标及临界值,指导现场防突措施的效果,对实验室相关参数进行分析并收集整理历史资料,筛选确定工作面突出危险性预测敏感指标及其临界值初始值,最后采用三率法和灰色关联法,确定突出煤层工作面突出危险性预测敏感指标临界值。根据乌兰煤矿掘进巷道的现场考察情况,确定了7#煤层突出危险性预测敏感指标为钻屑瓦斯解吸指标k1值及钻屑量指标S值,其临界值在正常地质条件下k1值为0.48 m L/(g·min0.5)、钻屑量S值为4.82 kg/m;在异常地质条件下k1值为0.38 m L/(g·min0.5)、钻屑量S值为3.85 kg/m。
