| China has a vast territory,intricately distributed terrains and complex geological structures.With the development of social economy,all kinds of construction projects are increasing,and the geological environment has a significant impact on engineering activities.In order to ensure the safety,feasibility and future use safety in the process of engineering construction,in the meantime to reduce the development cost of the project construction,it is necessary to make reasonable planning before the start of the project,and study the geological information from multiple perspectives.In this regard,3D visualization models can be used to reproduce 3D geological information,accurately obtain information and analyze foreseeable problems,so as to achieve effective planning and design of the project.In real life,most geological bodies are not simple layered structures.There are usually complex geological phenomena as faults,lens,fractures and so on.A certain research area in Guizhou selected in this paper contains a large number of karst caves.Engineering activities in the area containing karst caves may cause damage to the strength of the rock mass under the action of external loads and the environment,and even cause karst collapse,which affects the stability of engineering construction.And the safety of construction.Therefore,for complex geological areas,the geological body needs to be more intuitive,clear and realistic to achieve further control of engineering activities.This paper proposes to integrate ground and underground information to build a three-dimensional model of above-ground buildings,underground structures and stratigraphic geological bodies.Realize the integrated expression of above-ground and below-ground information.Because of the limitations of time,environment,cost,etc.,it can provide less data for geological modeling in practical engineering.For this reason,this paper is especially focuses on complex geological areas with less geological data information,and proposes to use Python to extract borehole information from histogram and add section diagram to modeling process to make full use of existing geological information.Then based on the GoCAD modeling platform,with the help of its discrete smooth interpolation method and UVT conversion technology to realize the construction of 3D geological model in its workflow,the main research work is as follow:(1)Comparison and selection of modeling methodsThis paper selects the grid model object to generate the geological body,which can be generated by two methods:the Geologial Grid or the hexahedron model(SGrid).In order to select a suitable modeling method,taking a region with faults as an example,the GoCAD platform workflow(Structure and Stratigraphy Workflow)is used to generate geological body model and the geological body model is established by SGrid that gengerated by Object box method are compared and analyzed.(2)Geological data preprocessingCollect the geological exploration information of the research area and preprocess the existing geological data.For the missing borehole information,the scripting language Python is used to extract the borehole histogram in CAD and convert it into Excel format.Secondly,make full use of the geological section map to extract the coordinates of the key points on the karst cave outline to prepare for the construction of karst cave model.In addition,due to the uneven sparse borehole data,It is proposed to perform Kriging interpolation on the existing borehole data,and use the modified borehole data points as discrete points of the formation interface.The stratum distortion generated in the subsequent modeling of interpolation is proposed to be solved by the discrete smooth interpolation technology in GoCAD.(3)Construction of 3D geological modelThe three-dimensional geological model of the research area is constructed according to the SKUA-GoCAD Structure and Stratigraphy workflow modeling method.The borehole data is converted into data points of each stratum,and input into GoCAD based on the form of columns.At the same time,it is necessary to determine the corresponding stratum mark of the hole at a certain position;Setting the stratigraphic sequence and using the contact relationship between the strata to create Stratum column,and determine the boundary(modeling domain and depth domain)of the geological model that is,defining the area of interest(VOI);first generate a preview stratigraphic model in the workflow,check the quality of the data and stratigraphic model,and then set Cell thickness,preview the generated geological grid model to control the accuracy of the geological model and build the final stratum.(4)Construction and embedding of special geological body-karst cave modelThe cave spheroid surface is constructed by contour point,and the formed independent cave is embedded in the formation surface model through the area of the rock carving geological mesh,to realize the model construction of complex geological area.In order to realize the position relationship between the cave and the geological section surface,the area occupied by the non-filled hollow cave can be treated blankly,and the cave can be distinguished in the display of three-dimensional geological model by defining the karst property division.(5)Realize the integration of above-ground and underground spatial informationUsing the layout plan of the research area,to extract the building contour,and the GoCAD platform generates the building surface model according to the building contour information and the height of the building;Secondly,according to the spatial position coordinates,the building model and the geological body model are integrated,and display the three-dimensional situation of the geological body and the aboveground buildings at the same time.Assuming the existence of underground structures such as tunnels,the tunnel model is established and integrated with the above-ground buildings and geological bodies,through geological sectioning at any angle,the positional relationship between the above-ground and underground buildings and the geological body can be obtained,so as to realize the integrated expression of the aboveground buildings and underground information. |
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