基于数字图像像素单元建立准三维FLAC3D模型

在实际应用中，即使是建立较为简单的不规则准三维模型，FLAC3D也存在一定难度，因此，提出了一种快速建立FLAC3D准三维模型的方法，即基于数字图像像素单元的位置属性建立FLAC3D准三维模型，并根据像素单元的颜色属性对所建立模型进行分组，以便实现对模型单元赋予不同属性材料或者建立不同功能模块（如开挖、回填）。借助上述思想，采用Visual Basic语言编写了IMAGE-FLAC3D接口程序，实现了FLAC3D软件建模的直观、快速和自动化。通过建立土石混合体有限差分模型和库岸滑坡有限差分模型，检验了该方法及程序的有效性和可行性。在此基础上，借助强度折减法对所建立库岸滑坡模型进行稳定性分析，分析结果与极限平衡法所得结果相近，说明了所建模型的可计算性。该方法可作为数字图像服务于岩土工程的典型范例。

Quasi-3D FLAC3D model generation based on pixel units of digital image

During the application of fast Lagrandian analysis of continua in 3 dimensions (FLAC3D), even for some simple irregular geologic bodies, the generation of quasi-3D numerical model with FLAC3D is difficult to construct. A new modeling method is put forward and an interface program of IMAGE-FLAC3D is realized by visual basic language in order to build numerical model of FLAC3D based on pairs of pixel units index numbers (i, j) and give the element different properties as well as different function modules(such as excavation, backfill) based on the color attribute of pixels. Through the interface program of IMAGE-FLAC3D, we can easily generate a microscopic and macroscopic irregular quasi-3D model based on the digital image in a short time. Then a finite difference model of soil-rock mixture and a finite difference model of landslide are developed, which show the feasibility of IMAGE-FLAC3D. The case study shows that the intuition, fastness and automation of modeling can be realized. Finally, the stability of landslide is analyzed by strength reduction method, whose results(such as the safety factor and the location of most dangerous slip surface) are in better agreement with those calculated by limit equilibrium method, which shows the computability of the model from IMAGE-FLAC3D. In a word, this paper gives a typical example that the digital image serves geotechnical engineering.