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为实现数值模拟获得的各种场数据与GIS空间信息的综合集成,有必要对GIS中融合有限元数值计算的方法开展研究。本文采用GRASS GIS、VTK等开源软件,通过Python语言建立了GIS与有限元模拟的复合系统开发框架,针对隧道开挖编写了3DGIS与有限元数值计算无缝耦合分析程序(3DPy Gis TFEM)。给出了由中心线上多条轮廓线生成隧道模型的算法,提出了对各地层DEM与隧道模型进行剖切运算获得隧道开挖地质剖面的方法。引入Delaunay网格剖分算法,对GIS中TIN模型不断改良,获得了适合有限元模拟的地质剖面三角形网格。基于多个剖面计算结果,运用插值手段,形成研究区域场数据,结合GIS空间分析方法,对场数据分布规律进行综合分析,实现了GIS与有限元的无缝耦合。黄家寨隧道工程实例表明,相对坡度、隧道中心线缓冲区等因素,地表距隧道拱顶高差的空间分布特征与地表沉降规律相关性更强。
In order to realize the integrated integration of various field data and GIS spatial information obtained by numerical simulation, it is necessary to study the method of integrating finite element numerical calculation in GIS. In this paper, we use GRASS GIS, VTK and other open source software to build the composite system development framework of GIS and finite element simulation through Python language. 3DPy Gis TFEM is compiled for tunnel excavation. The algorithm of generating tunnel model from multiple contour lines on the center line is given. The method of cutting the geological profile of tunnel excavation by cutting the DEM and tunnel model of each stratum is proposed. The Delaunay meshing algorithm was introduced to improve the TIN model in GIS. The geologic profile triangular mesh suitable for finite element simulation was obtained. Based on the results of multiple section calculations, the field data of the study area is formed by means of interpolation, and the spatial distribution of the field data is analyzed with the GIS spatial analysis method. The seamless coupling between GIS and the finite element is achieved. The Huangjiazhai tunnel project shows that the spatial distribution characteristics of the height difference of the tunnel roof from the relative slope and the tunnel centerline buffer are more relevant to the law of surface subsidence.