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栾茂田, 金崇磐, 林皋. 非均质地基上浅基础的极限承载力[J]. 岩土工程学报, 1988, 10(4): 14-27.
引用本文: 栾茂田, 金崇磐, 林皋. 非均质地基上浅基础的极限承载力[J]. 岩土工程学报, 1988, 10(4): 14-27.
Luan Maotian, Jin Chongpan, Lin Gao. Ultimate Bearing Capacity of Shallow Footings on Non-Homogeneous Soil Foundations[J]. Chinese Journal of Geotechnical Engineering, 1988, 10(4): 14-27.
Citation: Luan Maotian, Jin Chongpan, Lin Gao. Ultimate Bearing Capacity of Shallow Footings on Non-Homogeneous Soil Foundations[J]. Chinese Journal of Geotechnical Engineering, 1988, 10(4): 14-27.

非均质地基上浅基础的极限承载力

Ultimate Bearing Capacity of Shallow Footings on Non-Homogeneous Soil Foundations

  • 摘要: 本文根据塑性极限平衡原理,考虑地基土性的成层分布及粘结力沿深度的非均匀变化,结合变分法,推导了用于确定成层非均质地基极限承载力的基本公式,并采用拟牛顿算法进行了数值求解;基于大量计算结果,分析了土壤强度及其分布、基础埋深、地震荷载及地下水位深度等各种参数及其组合对地基承载力的影响,并将计算结果与已有的解答进行了比较。最后,对非均质地基承载力的表示方法进行了初步探讨。

     

    Abstract: In this paper, a method for solving the ultimate bearing capacity of shallow footings on non-homogeneous foundations is developed. The method is based on the limit equilibrium principle and a variational technique is utilized. Layered deposits of soil with cohesion varied non-uniformly with its depth are considered. Pseudostatic equilibrium equations for the footing-foundation system are formulated where the Coulomb's criterion Is applied to the rupture surface. The effect of earthquake on the soil foundation is taken into account by using a pseudostatic acceleration coefficient. Then, the Lagrange's undetermined multiplier method is used to construct the functional of the actual problem. The Euler's equations, and the variational boundary conditions including the condition of transversality at the end point and the reflection conditions at joint points between two soil layers, are found by minimizing the applied vertical load in the constructed functional. They are accompanied by the geometric boundary conditions. After solving this boundary value problem, the critical type of the rupture surface and stress distributions along the surface can be determined, and the limit loads can be easily estimated.The discrete Brown's arithmatic is employed to solve the non-linear implicit equation set for predicting the ultimate bearing capacity of non-homogeneous soil foundation and for determining the ralated critical parameters. The effects of footing and layered soil property parameters on the bearing capacity are systematically studied. These parameters are soil cohesions and their variation in the layer, internal friction angles, embedment of footings, layer thickness, pseudostatic seismic acceleration coefficient, ground water level, etc. The combinations of these parameters are also considered. The computational results by this method are compared with those by other authors and with published experimental results. Finally, a simple formula for prediction of bearing capacity is suggested.

     

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