黏土中条形锚板基础上拔极限承载力变分解法

Determination of Ultimate Uplift Capacity of Plate Anchors in Homogeneous Saturated Clay by Variational Solution

针对均质饱和黏性土中锚板基础上拔承载力问题,当锚板基础处于破坏极限平衡状态时,运用Mohr-Coulomb屈服准则建立静力学平衡方程式,结合变分法原理得到锚板基础下方土体破坏滑裂面基本方程以及破坏滑裂面上正应力分布方程,进而得到锚板基础的极限上拔承载力。通过该理论计算分析了土体不排水强度、荷载偏心率及水平荷载对极限上拔承载力、破坏滑裂面以及承载系数的影响。结果表明,该方法适合锚板基础快速上拔情况,荷载偏心对上拔承载力的影响更大,当偏心率e<0.5时,上拔极限状态下锚板与底部地基土体不发生分离;同时,提出了考虑荷载偏心和水平力作用时锚板基础上拔极限承载系数公式。

Limited equilibrium theory and variational method are used together to analyze the ultimate uplift capacity of strip anchor embedded in homogeneous saturated clay, where soil stresses satisfy the yielding criteria of Mohr-Coulomb in limited conditions. The function of sliding surface, the normal stress distribution along it, and ultimate uplift capacity can be obtained by this method. And the effects of soil strength, loading eccentricity, and horizontal loading on failure surface and uhimate uplift capacity are investigated by a series of calculations. It is concluded that the method can be applied to predict the ultimate uplift capacity of plate anchors of saturated clay under rapid uplift and loading eccentricity presents more significant influences on uplift capacity and sliding surface. When loading eccentricity is less than 0.5, the breakaway between plate and its underneath soil will not take place. Also, the formulas of factors of ultimate uplift capacity are suggested under central, eccentric uplift loadings and horizontal loading.