混凝土面板堆石坝的水下面板裂缝形成发展,影响了面板的工作性态。为揭示水下面板裂缝的成因,依据监测资料研究了运行期不利温度工况及施工质量对面板裂缝的影响,提出以空隙率的概率分布函数表征施工质量的方法,采用质量保证率模拟堆石区的施工缺陷区域,确定了运行期堆石坝面板裂缝分析的流程。以某混凝土面板堆石坝为例,通过结构计算研究了面板裂缝开裂区域的应力情况及变化趋势。结果表明:温度因子对深水区裂缝产生及发展影响不大。在水荷载作用下,当施工质量缺陷区堆石料质量保证率为90%时,计算的裂缝应力符合裂缝的检查情况,验证了该模拟方法的合理性。研究成果对面板堆石坝的安全运行具有工程意义,也对同种坝型运行期水下裂缝的成因和判断具有参考价值。

The working behavior of face slab of concrete face rockfill dam (CFRD) is affected by the formation and development of cracks in underwater face slabs in operation period. In the purpose of revealing the causes of underwater cracks, the influences of unfavorable temperature conditions and construction quality on cracks of concrete face slab in operation period were analyzed based on monitoring data. A method was put forward to characterize the construction quality by the probability distribution function of void fraction. The construction defect area in rockfill area was simulated using quality assurance rate, and finally the process of analyzing cracks of concrete face slab in operation period was determined. With a CFRD as an example, the stress situation and change trend of the cracking area of concrete face slab were studied via structural calculation. Results suggested little influence of temperature factor on the generation and development of deep underwater cracks. When the quality assurance rate of rockfill construction in the construction quality defect area reached 90% under the action of water load, the calculated crack stress conformed with the crack inspection results, which verified the rationality of the simulation method. The research finding is of engineering significance for the safe operation of CFRD, and could be taken as reference for the cause analysis and judgment of underwater cracks of CFRD during operation.