考虑拱效应的高面板堆石坝流变收敛机制研究

采用一种能模拟高围压条件的堆石料幂函数流变本构模型，探讨狭窄河谷条件下堆石体流变变形的发展规律及相应的控制流变变形的工程措施。数值仿真结果表明，在狭窄河谷中的堆石体存在着拱效应。由于拱效应的影响，如果不考虑堆石体流变导致拱效应减弱而增加的附加变形，数值仿真计算得到的大坝变形将小于其真实的变形。受拱效应影响，堆石体初期变形的速率受到抑制，但随着坝体的升高、蓄水后水压力的加大以及堆石体随时间发展等流变变形因素的影响，堆石体中的拱效应逐渐减弱。要减小面板浇筑后由于其下卧的堆石体流变产生的附加变形，可以尽量利用面板过水及堆石体挡水，以加快堆石体流变变形的完成。采取措施，避免大的陡坡突变以及面板浇筑时间滞后其下卧堆石体断面几个月。

Study of creep convergence mechanism of high concrete face rockfill dam with consideration of rockfill arch action

Based on a new kind of rockfill power function creep constitutive model which can simulate high confining pressure state of rockfill, the developing rule of rockfill creep and the engineering method of control creep are studied. The results show that the computation value of dam deformation will be less than the real one without consideration of rockfill creep because of arch action. The creep of the rockfill during early stage is suppressed. But the arch action will be weakened with heightening of dam, increasing of water pressure and developing of rockfill creep. The temporary section of CFRD is made use of blocking water or overflowing as possible in order to decrease rockfill creep during late stage. The construction date of the face slab delays several months than the rockfill below the face slab, which can rockfill creep.