论文部分内容阅读
坝踵应力是关系到混凝土坝是否开裂和安全的一个重要指标,不管是用结构力学法还是有限元法都能计算出坝踵有一定的拉应力,但实际监测中却很少出现。本文从定性和定量两个方面分析造成计算结果和实测结果差异的原因,以小湾特高拱坝为例分析影响计算精度的各项主要因素,在此基础上提出坝踵真实应力的仿真分析方法。结果显示,计算和实测应力差异原因主要在于以下3个方面:(1)坝踵位置的定义不同;(2)目前监测仪器和方法有局限性;(3)计算过程中的不当简化,如自重和水压的施加方式、坝体温度荷载的考虑、库水温度分布以及库盆水压的影响等。改进后的仿真分析结果与监测结果吻合良好,说明该方法能够给出合理的坝踵应力变化规律和比较精确的应力范围。最后,给出了坝踵应力监测仪器和方法的改进建议。
Dam heel stress is an important index that relates to the cracking and safety of concrete dams. Whether the structural mechanics method or the finite element method can calculate the heel has a certain tensile stress, but the actual monitoring is rare. This paper analyzes the causes of discrepancies between calculated and measured results from both qualitative and quantitative aspects. Taking Xiaowan UHV arch dam as an example, the main factors affecting the accuracy of the calculation are analyzed. Based on this, the simulation analysis of the real stress of the heel method. The results show that the difference between the calculated and measured stress mainly lies in the following three aspects: (1) the definition of the dam heel is different; (2) the current monitoring instruments and methods have limitations; (3) the improper simplification in the calculation process And the way of applying water pressure, considering the dam temperature load, the temperature distribution of reservoir water and the influence of reservoir pressure. The improved simulation results are in good agreement with the monitoring results, which shows that this method can give reasonable dam heel stress variation and more accurate stress range. Finally, some suggestions for improvement of dam heel stress monitoring instruments and methods are given.