拱梁分载法计算模型的改进和实现

The improvement and implementation of arch girder distribute load method calculation model

拱梁分载法是现行规范规定的计算拱坝应力的主要方法。然而在实际计算过程中,引入了一些结构力学的假定,不能准确考虑拱梁空间曲线的特性,如拱梁截面等效为矩形,伏格特公式的粗略计算等,影响了计算结果的精度。基于拱梁分载法基本原理,与有限元法相结合,可以更好地反映拱坝的力学特性。首先,利用有限元方法计算地基的刚度,可以考虑空间河谷地形及地基地质条件不均匀性影响,同时,利用有限元商业软件ANSYS中的梁单元,可以建立更为精确的拱梁模型,考虑拱坝轴线的空间扭曲特性及拱断面形状变化的影响。计算结果表明,改进的与有限元法相结合的方法可以考虑复杂的地基特性,且方法简单快捷,物理意义明确,有利于工程的实际应用。该方法为准确、合理地求解拱坝基础变位提供了参考。

The trial load method specified by the present standard codes, is the most widely used method for the stress analysis of arch dams. However, it is not accurate to take the characteristics of spatial curve of arch dams into account due to some simple assumptions. For instance, cross section is equivalent to rectangular, the approximation to the infinite foundation by the Voigt formula, and so on. In this paper, in order to improve the accuracy of trial load method, the Finite Element Method is employed to model system of arch-beam and foundation. Stiffness of foundation is calculated by Finite Element Method and the shape and the heterogeneous geology of valley are considered The geometry shape of arch and beam is modeled by the beam element provided by finite element software ANSYS so that spatial distortional property of arch axis and cross-section change of arch dam can be model more accurately. The results show that the improved method combing with the finite element method can be applied to more complicated foundations. Its simple and clear physical significance favors to practical application. The effect of foundation on the response of arch dam will be considered accurately in the proposed algorithm.