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面板挤压破坏是影响超高面板堆石坝安全的核心问题。总结分析了国内外数座典型超高面板堆石坝工程中发生的面板挤压破坏现象及特征。论述了面板纵缝转动接触挤压效应的发生机制,认为由坝体变形所导致的面板转动挤压和位移挤压是导致面板发生挤压破坏的本质原因。基于非线性接触力学的方法,自主开发了可描述面板坝复杂多体接触特性的计算方法和三维有限元计算程序系统。使用局部子结构模型对面板纵缝的转动接触挤压效应进行了分析。计算结果表明,转动挤压和位移挤压均可在纵缝两侧面板表面部位引发严重的应力集中,可从量值上解释面板发生挤压破坏时面板中部挤压应变实测值和计算值仍远低于混凝土极限抗压应变的现象。
The panel extrusion failure is the key issue that affects the safety of CFRD. The phenomenon and characteristics of panel extrusion failure occurred in several typical ultra-high CFRD dams at home and abroad are summarized and analyzed. The mechanism of contact squeeze effect of the longitudinal seam of the panel is discussed. It is considered that the rotational compression and displacement extrusion of the panel caused by the deformation of the dam are the essential causes of the extrusion failure of the panel. Based on the nonlinear contact mechanics method, a computational method and a three-dimensional finite element program system describing the complex multi-body contact characteristics of a panel dam are developed independently. The local sub-structure model is used to analyze the rolling contact squeeze effect of the longitudinal seam of the panel. The calculation results show that both rotational compression and displacement extrusion can cause serious stress concentration on the surface of the slab on both sides of the longitudinal seam, which can explain the measured value and the calculated value of the compressive strain in the middle of the panel Far below the ultimate compressive strain of concrete phenomenon.