运行条件对拱坝下游面水平裂缝的影响

Effects of Operation Condition on Horizontal Cracks in the Downstream Face of Arch Dams

本文回顾了几座混凝土拱坝在运行期,下游面中、上部位产生水平裂缝,和已有水平裂缝不断扩展的经过。根据实测资料,反馈分析了环境温度和运行水位对这种裂缝的影响机制,指出高温、低水位又紧接低温、低水位组合条件,对于下游面水平裂缝的产生或扩展,都是不利运行状态。在总结处理效果正反经验的基础上,得出了以下结论:由于下游面水平裂缝是受环境温度和运行水位影响的不稳定活缝,采取工程处理措施的同时,必须消除不利的运行组合条件,否则,将难于达到预期处理目的。

The paper reviews the development of horizontal cracks on the upper section of downstream face of a few concrete arch dams during operation and the continuous propagation of existing horizontal cracks. Feedback analysis of the influence of environmental temperature and operation water level on this kind of cracks are carried out based on the measured data. The combined operation conditions of high temperature, low water level immediately following low temperature, low water level may cause devlopment and propagation of horizontal cracks on downstream face. Summing up both positive and negative experince of treatment, it is concluded that because unstable active horizontal cracks on the downstream face are effected by environmental temperature and operation water level, while taking treatment engineering measures, it is necessary to eliminate unfavorable combined operation conditions leading to crack propagation. Otherwise,the desired results will not be achieved.