3D geological modeling, one of the most important applications in geosciences of 3D GIS, forms the basis and is a prerequisite for visualized representation and analysis of 3D geological data. Computer modeling of geo...3D geological modeling, one of the most important applications in geosciences of 3D GIS, forms the basis and is a prerequisite for visualized representation and analysis of 3D geological data. Computer modeling of geological faults in 3D is currently a topical research area. Structural modeling techniques of complex geological entities contain- ing reverse faults are discussed and a series of approaches are proposed. The geological concepts involved in computer modeling and visualization of geological fault in 3D are explained, the type of data of geological faults based on geo- logical exploration is analyzed, and a normative database format for geological faults is designed. Two kinds of model- ing approaches for faults are compared: a modeling technique of faults based on stratum recovery and a modeling tech- nique of faults based on interpolation in subareas. A novel approach, called the Unified Modeling Technique for stratum and fault, is presented to solve the puzzling problems of reverse faults, syn-sedimentary faults and faults terminated within geological models. A case study of a fault model of bed rock in the Beijing Olympic Green District is presented in order to show the practical result of this method. The principle and the process of computer modeling of geological faults in 3D are discussed and a series of applied technical proposals established. It strengthens our profound compre- hension of geological phenomena and the modeling approach, and establishes the basic techniques of 3D geological modeling for practical applications in the field of geosciences.展开更多
A numerical model based on a Continuum-based Distinct Element Method(CDEM) was used to carry out a dynamic simulation of the interaction between shield and rock strata movement in longwall mining. In Northern China, t...A numerical model based on a Continuum-based Distinct Element Method(CDEM) was used to carry out a dynamic simulation of the interaction between shield and rock strata movement in longwall mining. In Northern China, the Ordos coal field geological conditions and operational characteristics were used as a case example. The CDEM was constructed on Ordos coal field shield's operation characteristics and geological conditions. Numerical modelling was carried out to investigate the effects of different mining heights on the caving process, movement characteristics, equilibrium and stability conditions of overburden as the interaction between shield and surrounding rocks. With the numerical model, the internal factors for changes in shield resistance under different mining heights was found. The quantitative relationship between mining heights and shield resistance was also obtained by the numerical simulation.展开更多
The purpose of the investigation was to assess the opportunity to use spring waters as indicator for the load state of rural landscape ecosystems. In the periods from 2000-2003 and 2011-2012, the physical and chemical...The purpose of the investigation was to assess the opportunity to use spring waters as indicator for the load state of rural landscape ecosystems. In the periods from 2000-2003 and 2011-2012, the physical and chemical water quality of 55 freshwater springs in the German federal state of the Saarland was investigated in monthly intervals. The catchment areas of the springs represented the prevailing geological formations in the Saarland as well as the main land use types such as forest, grassland and arable land. The results show a clear correlation between the nitrate content and the share of arable land in the closer catchment area of the springs. The problem of acidification and related processes occurs mainly at the sites with acid parent rock material and accordingly substrates deficient in lime. Very low pH-values between 4 and 5 are observed and the aluminum concentration levels are consistently increased. Especially at sites with low calcium content in the geological substrate, a progressive destruction of the clay minerals can be assumed. In the extremely acidic spring waters, which showed the highest aluminum contamination during the measurement 10 years ago, the aluminum-values decreased slightly. This indicates that the clay minerals in these locations are already completely destroyed. Thus, it can be concluded that the investigation of spring waters provides information on the geo-ecological conditions in catchment areas. By means of the multi-temporal approach, changes of land use or other influences by human activities can be detected.展开更多
A surface spline function is used to fit a coal seam surface in structural anal ysis in coal geology. From the surface spline function, the first and second partial derivatives can also be derived and used to structur...A surface spline function is used to fit a coal seam surface in structural anal ysis in coal geology. From the surface spline function, the first and second partial derivatives can also be derived and used to structural analysis, especially for recogni tion of the concealed structures. The detection of structures related to faulting is em phasized.展开更多
In order to carry out numerical simulation using geologic structural data obtained from Landmark(seismic interpretation system), underground geological structures are abstracted into mechanical models which can reflec...In order to carry out numerical simulation using geologic structural data obtained from Landmark(seismic interpretation system), underground geological structures are abstracted into mechanical models which can reflect actual situations and facilitate their computation and analyses.Given the importance of model building, further processing methods about traditional seismic interpretation results from Landmark should be studied and the processed result can then be directly used in numerical simulation computations.Through this data conversion procedure, Landmark and FLAC(the international general stress software) are seamlessly connected.Thus, the format conversion between the two systems and the pre-and post-processing in simulation computation is realized.A practical application indicates that this method has many advantages such as simple operation, high accuracy of the element subdivision and high speed, which may definitely satisfy the actual needs of floor grid cutting.展开更多
During subduction processes, slabs continuously have heat exchange with the ambient mantle, including both conduction and advection effects. The evolution of slab thermal structure is one of the dominant factors in co...During subduction processes, slabs continuously have heat exchange with the ambient mantle, including both conduction and advection effects. The evolution of slab thermal structure is one of the dominant factors in controlling physical and chemical property changes in subduction zones. It also affects our understanding of many key geological processes, such as mineral dehydration, rock partial melting, arc volcanism, and seismic activities in subduction zones. There are mainly two ways for studying thermal structure of subduction zones with geodynamic models: analytical model and numerical model. Analytical model provides insights into the most dominant controlling physical parameters on the thermal structure, such as slab age, velocity and dip angle, shear stress and thermal conductivity, etc. Numerical model can further deal with more complicated environments, such as viscosity change in the mantle wedge, coupling process between slabs and the ambient mantle, and incorporation of petrology and mineralogy. When applying geodynamic modeling results to specific subduction zones on the Earth, there are many factors which may complicate the process, therefore it is difficult to precisely constrain the thermal structure of subduction zones. With the development of new quantitative methods in geophysics and geochemistry, we may obtain more observational constraints for thermal structure of subduction zones, thus providing more reasonable explanations for geological processes related to subduction zones.展开更多
基金Project 2001AA135170 supported by the National High-Tech Research and Development (863) Program of China and 06ZR14031 by the Natural ScienceFoundation of Shanghai Municipality
文摘3D geological modeling, one of the most important applications in geosciences of 3D GIS, forms the basis and is a prerequisite for visualized representation and analysis of 3D geological data. Computer modeling of geological faults in 3D is currently a topical research area. Structural modeling techniques of complex geological entities contain- ing reverse faults are discussed and a series of approaches are proposed. The geological concepts involved in computer modeling and visualization of geological fault in 3D are explained, the type of data of geological faults based on geo- logical exploration is analyzed, and a normative database format for geological faults is designed. Two kinds of model- ing approaches for faults are compared: a modeling technique of faults based on stratum recovery and a modeling tech- nique of faults based on interpolation in subareas. A novel approach, called the Unified Modeling Technique for stratum and fault, is presented to solve the puzzling problems of reverse faults, syn-sedimentary faults and faults terminated within geological models. A case study of a fault model of bed rock in the Beijing Olympic Green District is presented in order to show the practical result of this method. The principle and the process of computer modeling of geological faults in 3D are discussed and a series of applied technical proposals established. It strengthens our profound compre- hension of geological phenomena and the modeling approach, and establishes the basic techniques of 3D geological modeling for practical applications in the field of geosciences.
基金funded by the National Natural Science Foundation of China (Nos. U1261207 and 51274086)
文摘A numerical model based on a Continuum-based Distinct Element Method(CDEM) was used to carry out a dynamic simulation of the interaction between shield and rock strata movement in longwall mining. In Northern China, the Ordos coal field geological conditions and operational characteristics were used as a case example. The CDEM was constructed on Ordos coal field shield's operation characteristics and geological conditions. Numerical modelling was carried out to investigate the effects of different mining heights on the caving process, movement characteristics, equilibrium and stability conditions of overburden as the interaction between shield and surrounding rocks. With the numerical model, the internal factors for changes in shield resistance under different mining heights was found. The quantitative relationship between mining heights and shield resistance was also obtained by the numerical simulation.
文摘The purpose of the investigation was to assess the opportunity to use spring waters as indicator for the load state of rural landscape ecosystems. In the periods from 2000-2003 and 2011-2012, the physical and chemical water quality of 55 freshwater springs in the German federal state of the Saarland was investigated in monthly intervals. The catchment areas of the springs represented the prevailing geological formations in the Saarland as well as the main land use types such as forest, grassland and arable land. The results show a clear correlation between the nitrate content and the share of arable land in the closer catchment area of the springs. The problem of acidification and related processes occurs mainly at the sites with acid parent rock material and accordingly substrates deficient in lime. Very low pH-values between 4 and 5 are observed and the aluminum concentration levels are consistently increased. Especially at sites with low calcium content in the geological substrate, a progressive destruction of the clay minerals can be assumed. In the extremely acidic spring waters, which showed the highest aluminum contamination during the measurement 10 years ago, the aluminum-values decreased slightly. This indicates that the clay minerals in these locations are already completely destroyed. Thus, it can be concluded that the investigation of spring waters provides information on the geo-ecological conditions in catchment areas. By means of the multi-temporal approach, changes of land use or other influences by human activities can be detected.
文摘A surface spline function is used to fit a coal seam surface in structural anal ysis in coal geology. From the surface spline function, the first and second partial derivatives can also be derived and used to structural analysis, especially for recogni tion of the concealed structures. The detection of structures related to faulting is em phasized.
基金Projects 50221402, 50490271 and 50025413 supported by the National Natural Science Foundation of Chinathe National Basic Research Program of China (2009CB219603, 2009 CB724601, 2006CB202209 and 2005CB221500)+1 种基金the Key Project of the Ministry of Education (306002)the Program for Changjiang Scholars and Innovative Research Teams in Universities of MOE (IRT0408)
文摘In order to carry out numerical simulation using geologic structural data obtained from Landmark(seismic interpretation system), underground geological structures are abstracted into mechanical models which can reflect actual situations and facilitate their computation and analyses.Given the importance of model building, further processing methods about traditional seismic interpretation results from Landmark should be studied and the processed result can then be directly used in numerical simulation computations.Through this data conversion procedure, Landmark and FLAC(the international general stress software) are seamlessly connected.Thus, the format conversion between the two systems and the pre-and post-processing in simulation computation is realized.A practical application indicates that this method has many advantages such as simple operation, high accuracy of the element subdivision and high speed, which may definitely satisfy the actual needs of floor grid cutting.
基金supported by the National Basic Research Program of China(Grant No.2015CB856106)
文摘During subduction processes, slabs continuously have heat exchange with the ambient mantle, including both conduction and advection effects. The evolution of slab thermal structure is one of the dominant factors in controlling physical and chemical property changes in subduction zones. It also affects our understanding of many key geological processes, such as mineral dehydration, rock partial melting, arc volcanism, and seismic activities in subduction zones. There are mainly two ways for studying thermal structure of subduction zones with geodynamic models: analytical model and numerical model. Analytical model provides insights into the most dominant controlling physical parameters on the thermal structure, such as slab age, velocity and dip angle, shear stress and thermal conductivity, etc. Numerical model can further deal with more complicated environments, such as viscosity change in the mantle wedge, coupling process between slabs and the ambient mantle, and incorporation of petrology and mineralogy. When applying geodynamic modeling results to specific subduction zones on the Earth, there are many factors which may complicate the process, therefore it is difficult to precisely constrain the thermal structure of subduction zones. With the development of new quantitative methods in geophysics and geochemistry, we may obtain more observational constraints for thermal structure of subduction zones, thus providing more reasonable explanations for geological processes related to subduction zones.
