水平浅埋条形锚板极限抗拔力上限计算

作为一种提供抗拔力的基础形式，锚板在实际工程中有广泛的应用。在上限定理的基础上，根据线性破坏准则，对锚板上的填土建立机动容许的速度场，运用关联流动法则以及速度边界条件求解条形锚板极限抗拔力的上限解。把锚板上填土的抗剪强度指标c、? 作为变量参数，对锚板上部填土建立两种新的含有变量的容许速度场。根据外力功率与内部耗能相等原理，求出极限抗拔力的目标函数与约束条件，并根据“序列二次规划算法”对该问题进行优化。将研究结果与已有文献资料进行分析比较，可以证明本文方法的有效性。参数分析结果表明：在同样条件下，两种破坏模式的极限抗拔力差别不大；岩土体密实度、抗剪强度指标c、?、锚板埋深率和锚板几何形状对锚板承载能力和锚板抗拔破坏区域均有较大的影响。

Ultimate pull-out capacity of strip anchor plates with upper bound theorem

Soil anchors are commonly used as foundation systems for structures that require uplift or lateral resistance. Based on the upper bound limit analysis theorem, the linear Mohr-Coulomb failure criterion and associated flow rule, the ultimate pull-out capacity (UPC) of strip anchors is studied by means of the kinematical approach of limit analysis theory. The shear strength parameters (internal friction angle ? and cohesive force c) are treated as variable parameters and two new kinds of knematically admissible failure mechanisms are considered for the calculation schemes. The objective functions of UPC are obtained by equating the work rate of external force to internal dissipation along the velocity discontinuities; and then the upper bound solutions are presented by applying a nonlinear sequential quadratic programming (SQP) algorithm. The calculation results are compared with the available empirical and numerical results presented in the existing literatures, and the validity of present method could be illuminated. From the parameters analysis results, the UPC of new kinds of knematically admissible failure mechanisms is no significant difference. It also can be seen that the density of soil mass, the shear strength parameters (? and c), the embedment ratio and the plate geometric properties have significant effects on UPC and the region of failure modes.