基于GIS和体视化技术的工程场地地震液化势3D可视化

工程场地地震液化势三维模型的建立及可视化研究的目的是用三维图形来描述地震动作用下场地液化势的空间分布特性,以此为城市防震减灾工作提供相应的支持。采用具有概率意义的饱和砂土抗液化强度经验公式来对场地进行地震液化势概率评价;采用一种基于"块"模型的数据结构来描述场地液化势三维实体;结合Kriging插值法和体视化技术进行场地液化势的三维可视化建模。研究表明:采用"块"数据模型来分割模拟三维液化势场,利用Kriging法对工程场地地震液化势进行空间数据三维插值,有助于揭示勘探孔以外任意空间点的土层液化势信息;基于液化势概率评价结果和体视化技术,采用Kriging插值法,以不同的色标体现场地液化势的风险程度,可以直观的三维图像形式呈现场地液化势的空间分布特性和变化趋势,通过剖切自动生成指定位置的二维剖面和三维切割体,工程场地液化势的三维分布特性得到有效的表达。

3D visualization for earthquake-induced site liquefaction potential based on volume rendering and GIS technology

The researches on visual 3D modeling for the earthquake-induced site liquefaction potential are to resolve the problem of simulating the potential risk of earthquake-induced site liquefaction spatially by 3D reality graphics.And it could be applied to the urban earthquake prevention and disaster mitigation.Firstly,the empirical equation of cyclic resistance ratio of saturated sands with different probability levels was utilized to evaluate the earthquake-induced site liquefaction potential.Secondly,a "block" data structure was adopted to describe the 3D liquefaction potential entity.Thirdly,visual 3D visualization modeling for the earthquake-induced site liquefaction potential could be realized based on the Kriging interpolation method and volume rendering technique.It was shown that:(1) When the 3D liquefaction potential entity was partitioned by the "block" data model,the Kriging method can be adopted to realize 3D interpolation.Therefore,the latent distribution of the site liquefaction potential beyond the observation boreholes could be evaluated.(2) Based on the probability evaluation results and volume rendering technique,the Kriging interpolation results were displayed in different color marks to indicate the risk extent of the site liquefaction potential.Thereby,the spatial distributing characteristics and variety trend of the site liquefaction potential could be displayed in 3D graphic form.And also,the 2D profile section and 3D body incision could be generated automatically.