基于安全系数法拟定面板堆石坝变形监控指标

为解决当前拟定大坝变形监控指标未考虑大坝等级和重要性问题,首先,采用有限元强度折减法,建立面板堆石坝抗滑稳定安全系数与坝体上下游水位的关系式,根据大坝等级和重要性确定的坝坡抗滑稳定安全系数求出坝体上下游水位,计算坝体在该组水位作用下的水压位移;然后,依据面板堆石坝施工过程、蓄水及运行计划,采用堆石料三参数流变模型,计算坝体时效位移;最后,以某面板堆石坝为案例,拟定面板堆石坝变形一级监控指标。结果表明:提出的基于安全系数拟定面板堆石坝变形一级监控指标方法,可弥补常规分析法拟定变形监控指标不能考虑大坝等级和重要性的缺陷,完善拟定土石坝变形监控指标的理论和方法。

Monitoring index for deformation of face rockfill dam based on safety factor method

In order to solve the problem that grade and importance of dams are not considered in monitoring index of dam deformation,firstly,finite element strength reduction method was used to establish relationship between anti-sliding safety coefficient and stream and downstream water levels of face rockfill dams.The latter were obtained based on safety factor of dam slope which was determined by dam grade and importance,and hydraulic pressure displacement of dams was calculated.Secondly,threeparameter rheological model of rockfill material was used to calculate time-dependent displacement of dams according to construction process,water storage and operation plan.Finally,with a face rockfill dam as an example,first-level monitoring index for dam deformation was drawn up.The results show that the proposed method based on safety factor can make up for defects of conventional analysis method which lacks consideration of dam grade and importance,and it can improve theory and practical method for drawing up monitoring index for deformation of earth-rock dams.