Ubiquitous节理岩体模拟

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1 引言

Ubiquitous节理岩体模拟最初在FLAC中引入，Sainsbury等人(2008)在SRM中使用了UJRM，从而在FLAC3D模型中考虑了岩体强度和各向异性, 能够研究完整岩石内聚力的逐渐减弱和Ubiquitous节理破坏, [Sainsbury, B. et al. (2008) Analysis of cave behaviour using a Synthetic Rock Mass (SRM) – Ubiquitous Joint Rock Mass (UJRM) modelling technique.]，他们的方法与Pierce等人(2007)和Mas Ivars等人(2008)的方法不同，没有使用PFC3D，而是用FLAC3D评估来自较小模型模拟的岩体属性。Lavoie(2011) 提出了一个UJRM的解析解[Thierry Lavoie (2011) An Analytical Geomechanical Upscaling Approach for Modeling Jointed Rock Mass Behaviour Using Ubiquitous Joints. UBC MS. Thesis. 186p.]。这个笔记简要讨论了ADONIS的Ubiquitous本构模型，并与FLAC/Slope中的Ubiquitous模型作了比较。

2 ADONIS模拟

一个简单的Ubiquitous节理岩体边坡如下图所示。

(1) 项目设置

在项目设置中，主要设置合适的单位和重力加速度。

(2) 网格划分

边坡的几何形状可以在ADONIS内直接输入坐标，选择6节点的三角形单元，最大边长取0.75。

(3) 边界条件

边界使用xyfix命令固定三边，边坡面不能固定。

(4) 材料性质

输入如下的材料参数。

(5) 计算结果

计算的安全系数FOS=1.217, 使用相同的参数，FLAC/Slope计算的安全系数FOS=1.24。下图所示的最大剪应变等值线。

newmodel()set("unit","stress-pa")line("startPoint",0,0,"endPoint",52,0)line("startPoint",52,0,"endPoint",52,20)line("startPoint",52,20,"endPoint",32,20)line("startPoint",32,20,"endPoint",20,10)line("startPoint",20,10,"endPoint",0,10)line("startPoint",0,10,"endPoint",0,0)triangle("elemtype","T6")discretize("maxedge",0.75)triangle("maxedge",0.75)set("gravity",0,9.8)material("create","Ubiquitous-Joint","matid",1,"matname","Jointed Rock","density",2600,"shear",3e+07,"bulk",1e+08,"coh",100000,"fric",40,"jangle",30,"jcoh",5000,"jfric",25)material("assign","matid",1)applybc("xyfix","xlim",-0.1,0.1,"ylim",-0.1,10.1)applybc("xyfix","xlim",51.9,52.1,"ylim",-0.1,20.1)applybc("xyfix","xlim",-0.1,52.1,"ylim",-0.1,0.1)solve("fos")