特高拱坝温控防裂至关重要,本文总结了近期特高拱坝温控防裂研究与实践成果,对抗裂安全系数制定、温控标准制定及温控措施的优化选择、温控施工质量控制等关键问题进行了系统的论述。提出如下建议:(1)抗裂安全系数应取1.8-2.0,温差标准从严控制,可取全坝统一的基础温差标准,最高温度控制标准则按封拱温度和允许基础温差之和进行控制;(2)按"早保护、小温差、慢冷却"、"三期冷却"、"智能监控"即"九三一"温控模式进行全过程温度控制;(3)空间温度梯度按"拟灌区、同冷区、过渡区、盖重区"控制,时间上的温度过程按"三期多阶段"控制,中期控温与冷却至关重要;(4)采用智能化的手段对施工过程进行全程质量监控,必要环节采用智能温控措施。上述建议旨在为特高拱坝相关规范的制订和修编提供参考。
Temperature control and crack prevention are very important for super high arch dam. In this study,recent researches and practical achievement are summarized,while issues such as the identification of anti-crack safety factor and the standard of temperature control,the optimization and selection of temperature control measures,and the construction quality control are discussed systematically. Suggestions are proposed as follows.(1)The anti-crack safety factor should take the value range from 1.8 to 2.0,and the standard for temperature difference should be kept under strict control,taking the uniform foundation temperature difference standard for the whole dam,and controlling the highest temperature by the sum of arch sealing temperature and the standard foundation temperature difference.(2)The "931" temperature controlmode,namely"early protection,small temperature difference,and slow cooling","three-phase cooling"and"intelligent monitoring",should be adopted for full-process temperature control.(3)Spatial temperature gradient should be controlled in four zones:"ungrouted zone,simultaneous cooling zone,transition zone,andweighted cover zone",and the temperature process should be controlled in"three phases and multi-stages". The temperature control and cooling in the middle phase is essential.(4)Quality of the whole construction process should be monitored with intelligent tools,and intelligent temperature control measures should be taken for necessary steps. These suggestions are aimed at providing references for the editing and amend-ing of technical specifications related to super high arch dam.