河谷形状对面板堆石坝变形特性的影响研究

摘要

In order to study the influence of valley topography on deformation and stress characteristics of concrete face rockfill dam(CFRD), a new valley topography parameter has been given in this paper. This new parameter is described by using three parts, valley width coefficient μ, valley slope coefficient δ and valley asymmetry coefficient γ. The results of this study show that the foundation topography could restrain the deformation of dam and when the valley width coefficient is smaller, the restriction of the foundation on the dam becomes stronger. The restriction to the dam leads to the decrease of concrete slab deflection, while the later settlement value of rockfill caused by the arch effect is still great. The interaction between the two is the main reason of concrete face slab cracking happened in narrow deep valley. When the valley slope coefficient changes, the position of the shear failure plane in the rockfill is different, and the im-provement measures of concrete slab should be taken to adapt such changes. The uneven settlement on the dam increases with decreasing the valley asymmetry coefficient of the valley,and this uneven settlement re-sults in the torsion deformation of concrete face slab.%给出了新的河谷形状参数定义，采用河谷宽度系数μ、河谷边坡陡缓系数δ、河谷非对称系数γ三个动态参数来描述河谷形状。研究了新给出的河谷形状参数对面板堆石坝变形特性的影响，研究表明：河谷地形对坝体存在约束作用，河谷宽度系数越小，河谷地形对坝体的约束作用越强；河谷地形对坝体的约束作用减小了面板的挠度，而堆石体内部存在的应力拱效应则增大了坝体的后期沉降量，两者的共同作用是导致窄河谷中面板产生裂缝的主要原因；河谷边坡陡缓系数不同，堆石体内部潜在剪切滑动面的位置不同，面板的重点防护范围不同；河谷非对称系数越大，大坝发生不均匀沉降的范围越大，面板的扭曲变形越大。