单元集成法及其在土压力计算中的应用  

ELEMENT INTEGRATION METHOD AND ITS APPLICATION TO SOIL PRESSURE CALCULATION

作　　者：尹宏磊[1] 徐千军[1] 李仲奎[1] 

机构地区：[1]清华大学水沙科学与水利水电工程国家重点实验室,北京100084

出　　处：《岩石力学与工程学报》2006年第11期2346-2351,共6页Chinese Journal of Rock Mechanics and Engineering

摘　　要：基于塑性力学上限定理的土压力计算,在数值上可以通过单元集成法来实现。它采用类似于有限元网格划分的方式离散墙背土体,并设定一个机动许可的滑动机构。在此滑动模式下,可以求得每个单元贡献的外力功率和内能耗散率。所有单元的能量变化率的总和就是墒背土滑裂体的总能量变化率。然后,根据上限定理可以求得与滑动机构相对应的极限外载荷,并通过非线性数学规划法找到其最小值。采用平面和对数螺旋滑裂面的单滑块机制,对典型的二维土压力问题进行分析,其结果说明该方法的有效性。Gravity-type retaining wall is one of the most common structures in civil engineering; and the lateral earth pressure due to the backfill is generally a major factor for the design of this type of structure. The earth pressure can be calculated using limit analysis method based on upper bound limit theorem in plasticity. Besides the traditional methods discretizing the backfill into thin slices or using rigid finite element method, upper bound limit analysis can be also numerically performed by element integration method, which is induced in this paper. In the present method, small triangle elements are used to discretize the soil behind the retaining wall. A kinematically admissiable velocity field is supposed by mathematical equations containing two or three parameters. It is independent with the element mesh. The work done by the body forces, surface loads as well as internal energy dissipations within an element are convenient to be obtained under such a failure mechanism. The whole energy can be calculated from the energy integration among all the elements. The limit external load can therefore be solved from the upper bound limit theorem; and its minimum value can be obtained from optimization method. For single block mechanism, such as plane and log-spiral slip surface, the validity of this method has been verified by a typical two- dimensional example.

关 键 词：土力学 土压力 极限分析 上限法 单元集成法 

分 类 号：TU43[建筑科学—岩土工程]