边坡稳定分析的有限元极限平衡法原理及程序实现

发布时间：2018-03-28 16:30

本文选题：边坡稳定　切入点：有限元　出处：《北京交通大学》2014年硕士论文

【摘要】：边坡失稳是严重的灾害,对人类的生命财产带来重大的威胁,边坡稳定性分析有着重要的学术价值和经济社会价值。边坡稳定的主流分析方法有条分法和有限元强度折减法。条分法依赖条间力假定,并且在复杂条件下存在寻找临界滑动面的困难。而有限元强度折减法存在本构模型选择及安全系数判定准则等方面的争议。本文探讨了有限元极限平衡法分析边坡稳定的可能性。有限元极限平衡法是基于有限元计算应力场的极限平衡法,它避免了条分法条间力的假定和有限元强度折减法安全系数判定争议；将极限平衡分析和有限元应力场结合,计算边坡的安全系数。有限元极限平衡法的思路是：首先采用有限元分析软件计算边坡的应力应变场,得出边坡网格节点和高斯点的应力应变信息；然后根据边坡的应力应变和边坡的网格,采用双线性插值,便可求出边坡中指定的滑裂面的应力信息,进而根据极限平衡原理求出该滑裂面的安全系数；最后改变滑裂面的位置,搜索最危险滑动面,得出边坡的安全系数。本文根据有限元极限平衡法的原理,利用C#语言编写了相应的计算程序。该程序首先读入有限元应力应变场,然后对指定的直线滑面、圆弧滑面进行安全系数计算,并实现了临界滑裂面的搜索和边坡稳定系数的求解。笔者将新开发的有限元极限平衡法计算程序用于土质边坡稳定性分析,并将其计算结果和条分法,有限元强度折减法进行比较,获得了如下结论： 1.有限元极限平衡法对边坡稳定性评估的结果和传统条分法和有限元强度折减法计算结果相近,可以作为条分法和强度折减法评估边坡稳定性的有效补充。 2.有限元极限平衡法对边坡稳定性的评估受到有限元应力场的影响,基于弹性解应力场的计算结果相近于传统条分法计算结果,而基于塑性解应力场的计算结果更相近于有限元强度折减法计算结果。本文还进行了大变形分析方法用于边坡稳定性分析的尝试。对于变形较大的边坡工程,采用小变形有限元的模拟往往不收敛,导致模拟不能进行下去,而使用采用应力插值和网格重划分技术的Afena软件,能够直接模拟得到边坡失稳后的几何形式,准确评估边坡稳定的滑裂模式和和规模。
[Abstract]:Slope instability is a serious disaster, a great threat to human life and property, the slope stability analysis has important academic value and social and economic value. The slope stability analysis method is the mainstream of slice method and finite element strength reduction method. The method relies on the assumption of the force, and are difficult to find the critical slip in the face of complex conditions. And the strength reduction finite element constitutive model and the existing safety coefficient criterion of the dispute.
This paper discusses the finite element method of limit equilibrium analysis of the possibility of slope stability. The finite element method of limit equilibrium is the limit equilibrium method based on finite element calculation of the stress field, it avoids the assumption force method between finite element strength reduction method and evaluation of safety factor will be controversial; limit equilibrium analysis and finite element stress combined with the field, the calculation of safety factor of slope.
Finite element method of limit equilibrium method is: first using finite element analysis software to calculate the stress and strain field of the slope, the slope of grid nodes and Gauss stress strain information; then according to the slope and the slope should be grid strain, using bilinear interpolation, we can calculate the slope slip surface should be specified in the force information, then according to the limit equilibrium principle and calculating the slip surface safety factor; finally changed the location of slip surface, search the most dangerous sliding surface. The slope of the safety factor.
According to the principle of limit equilibrium method, using C# language to write the corresponding calculation program. The program first reads the finite element stress and strain field, and then the linear sliding surface is specified, safety factor calculation and implementation of circular slip surface, the critical slip search and slope stability coefficient of the solution.
The newly developed finite element limit equilibrium method is applied to analyze the stability of soil slope. The calculation results are compared with those of slice method and finite element strength reduction method.
1., the results of slope stability evaluation by finite element limit equilibrium method are similar to those calculated by traditional slice method and finite element strength reduction method, which can be used as an effective supplement for slope stability evaluation by slice method and strength reduction method.
Evaluation on slope stability of 2. finite element limit equilibrium method by finite element stress calculation, elastic solution of stress field results similar to the traditional slice method based on the computation results and plastic solution calculation of stress field in the phase to finite element strength reduction method based on the results.
The large deformation analysis method for slope stability analysis. Try to deformation of slope engineering is large, with small deformation finite element simulation is often not convergent, lead to carry on simulation cannot use the force interpolation and grid remeshing technology in Afena software, can be directly obtained after the geometric form of slope instability the accurate evaluation of the slope stability of sliding mode and scale.

【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU43

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