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将大曲率圆弧深拱稳定理论引入到拱坝抗曲折稳定分析中,考虑了曲率和剪切变形对拱坝水平拱圈稳定的影响,给出了临界荷载的计算公式,并构造出无铰圆弧拱失稳时超越方程的一种高效的迭代格式解,提出了拱坝水平拱圈抗曲折系数的概念。通过对典型拱坝及失事拱坝进行抗曲折稳定校核,与实际工程十分吻合,得到如下结论:对于拱坝上半部分离坝顶不远处,拱圈容易发生整体曲折失稳,但因上部曲率和厚度较小,使曲率和剪切变形对水平拱圈稳定临界荷载的影响不大;对于拱坝下半部分不容易发生整体曲折失稳,但因下部曲率和厚度较大,曲率和剪切变形使水平拱圈抗曲折稳定临界荷载明显降低,而且剪切变形对拱圈稳定临界荷载的影响大于曲率的影响;坝体和坝肩岩体之间的连接越接近固支水平拱圈越稳定。该文结论对相关规范的制定有参考价值。
In this paper, the stability theory of curved arch with large curvature is introduced into the anti-buckling stability analysis of arch dam. The influence of curvature and shear deformation on the stability of horizontal arch of arch dam is considered. The formula of critical load is given, An efficient iterative solution of the transcendental equation for a circular arch with instability is proposed, and the concept of anti-tortuosity coefficient of horizontal arch of arch dam is proposed. By checking the anti-buckling stability of the typical arch dam and the accident arch dam, the results are in good agreement with the actual project, and the following conclusions are obtained: For the upper half of the arch dam not far from the dam crest, The upper curvature and the smaller thickness make the curvature and shear deformation have little effect on the stability critical load of the horizontal arch ring. For the lower half of the arch dam, the overall buckling instability is not easy to occur. However, due to the lower curvature and thickness, The shear deformation reduces the critical load of horizontal arch against buckling and stability, and the influence of shear deformation on the stability critical load of arch ring is greater than that of curvature. The closer the connection between the dam body and the abutment rock mass is, The more stable. The conclusion of this article has reference value for the formulation of relevant norms.