混凝土大坝变形监控指标拟定的混合法

Hybrid method for deformation monitoring index of concrete dam

针对混凝土坝变形监控指标拟定涉及的材料参数众多且不容易准确获取的问题,考虑到水压分量数值计算涉及的参数相对较少且计算结果相对可靠,采用数值计算-变形统计模型的混合法拟定混凝土坝变形监控指标,即水压分量采用不利水位工况下数值计算值,其它分量则采用不利工况下变形统计模型的分离值或反映非线性效应的分量值,结合某常态混凝土高拱坝,提出了基于混合法拟定混凝土坝变形一级、二级监控指标。分析表明,基于混合法拟定的变形一级监控指标与典型小概率法拟定的监控指标接近但略大,这表明该拱坝目前处于黏弹性工作性态,但混合法拟定的变形一级监控指标考虑的因素更全面,而且材料性能分项系数的引入明确了强度参数的合理取值。

When the numerical computation method is adopted to determine the deformation monitoring in⁃dex of concrete dam,there exits great difficulties due to many material parameters of dam concrete and rock foundation and these parameters are not easy to obtain accurately.Since the numerical calculation of hydraulic pressure component involves relatively few parameters and the calculation results are relatively reli⁃able,the hybrid method of numerical computation method and statistical model of deformation is employed to determine the deformation monitoring index.Namely,the hydraulic pressure component is calculated by nu⁃merical computation method under the unfavorable water level loadcase,and the other components are ob⁃tained by using the separated values of statistical model or monitoring values reflecting nonlinear effects.Combined with a normal concrete high arch dam,the first-and second-level deformation monitoring index⁃es of concrete dam are analyzed.The research results show that the monitoring index based on the typical low probability method is close to but slightly smaller than the first-level deformation monitoring index based on the hybrid method,which indicates that the arch dam is in viscoelastic working state at present.However,the first-level deformation monitoring index determined by the hybrid method takes into account more comprehensive factors,and the introduction of component coefficient of material properties can present more reasonable value of strength parameters.