临坡地基承载力极限分析上限有限元数值模拟  

Numerical simulation of the bearing capacity of a foundation near slope using the upper bound finite element method

作　　者：赵明华[1] 胡啸[1] 张锐[1] 

机构地区：[1]湖南大学岩土工程研究所,湖南长沙410082

出　　处：《岩土力学》2016年第4期1137-1143,1152,共8页Rock and Soil Mechanics

基　　金：长沙市科技计划项目(No.K1203011-11)~~

摘　　要：与水平地面地基土体的对称破坏模式不同,临坡地基土体随不同工况呈现较明显的多种破坏模式。基于上限分析有限元技术,通过对临坡地基土建模,得到非线性上限规划模型,采用可行弧内点算法对其进行求解。将计算结果转换成相应的速度场和能量耗散图,并与文献结果进行对比分析。分析结果表明,上限有限元法能够较清楚地模拟出临坡地基破坏的几种模式,并得到合理解。通过把临坡地基承载力转为Terzaghi建议的分项系数叠加形式,对分项系数N_c、N_γ、N_q的变化规律进行讨论,发现N_c和N_q变化趋势基本符合现有的单调变化规律,但对于N_γ而言,由于破坏模式改变造成了破坏体体积变化,得到N_γ发生非单调改变的变化规律。以临坡基础完全不受斜坡影响的距离α_0/B作为绝对安全距离,并给出部分计算图表,为斜坡地基设计提供参考。In contrast with the level ground, which has a single symmetrical failure mode, foundation soil near the slope presents a variety of failure modes under different working conditions. Based on the upper bound finite element method, a nonlinear upper programming model is developed, in which a feasible arc interior point algorithm is used for solution. The calculation results are converted into the corresponding velocity field and the energy dissipation, and compared with the numerical results in the literature. It is shown that the upper bound finite element method can be used to effectively analyze the slope failure mode and obtain a reasonable solution. By converting the bearing capacity of slope into Terzaghi partial coefficient, and based on the variations of N_c、N_γ 、N_q, it is found that the variations of N_c and N_q are consistent with the existing monotonous change rule. As for N_γ, because the volume of the failure body changes due to the change of failure mode, a non-monotonous change rule of N_γ is observed. By defining the safe distance as the distance α_0 /B completely unaffected by the slope, part of the calculation chart is developed, providing a useful reference for slope foundation design.

关 键 词：临坡地基 极限分析 有限元单元法 破坏模式 

分 类 号：TU470[建筑科学—结构工程]