复合加载情况下非均匀地基上矩形基础承载力研究

Bearing capacity of rectangular footings on inhomogeneous foundation under combined loading

复合加载情况下,求解非均质地基上矩形基础的极限承载力,以及从理论上研究影响极限承载力的相关因素,具有很强的工程实用与理论参考价值。基于极限平衡原理,在Mohr-Coulomb破坏准则的基础上,将非均质地基上矩形基础极限承载力问题等价为一个边界待定的泛函极值问题。利用变分原理得到与平衡方程相等价的积分约束条件以及相应的欧拉方程与横截条件,在引入问题边界条件后,求得了复合加载情况下非均质地基破坏时的滑裂面方程。同时研究了土体内摩擦角、土体黏聚力、矩形基础长宽比、土层强度比与地下水位变化等因素对地基极限承载力的影响。

It was important to evaluate the ultimate bearing capacity of rectangular footings on inhomogeneous foundation under combined loading. Based on the limit equilibrium theory and the yielding criteria of Mohr-Coulomb, the equilibrium equation could be equivalently transformed to the format of functional extremum with undetermined boundary values by using the variational principle. The function of the 3D sliding surface and the failure envelope of rectangular footings on inhomogeneous foundation under combined loading was achieved when the boundary conditions were introduced. The effect of the angle of internal friction and the cohesion of soil, the ratio of L/B, the shear strength ratio ci/c1＋1 and the fluctuation of groundwater level on the ultimate bearing capacity of rectangular footings on inhomogeneous foundation and the failure envelop were studied.