基于应力-强度关系的拱坝温控曲线优化研究

Optimization of arch dam temperature control curve based on stress-strength relationship

现有拱坝“三期九阶段”温控曲线存在混凝土应力和抗裂安全系数波动大、性能未能充分发挥的问题。为优化拱坝应力状态,提出一种基于应力和强度关系的混凝土拱坝温控曲线确定方法,构造了优化目标函数,选定了基本线型和基于抛物线线型的温度控制曲线函数,采用仿真方法和室内试验进行了分析验证,并以西南某特高拱坝为例进行应用分析。结果表明:平滑型温控曲线减小了常规温控曲线导致的应力大幅波动变化,在合理线型下更有利于充分发挥材料性能;下凹型温控曲线相应的应力变化与强度发展规律更为一致,过程中抗裂安全系数稳定,是较优线型;温控曲线优化后,相同温度条件下最大应力明显减小,降低了混凝土开裂风险,相同安全系数条件下最高温度控制标准放宽,可降低温控难度,节省温控费用。该研究对混凝土坝智能温控和防裂具有重要意义。

The existing“three-phase,nine-step”temperature control curve for the arch dam presents the problem of large fluctuations in concrete stress and anti-cracking safety coefficient,and its performance is not fully utilized.To optimize the stress state of the arch dam,a method is proposed for determining the temperature control curve of the concrete arch dam based on the relationship between stress and strength.An optimization objective function is constructed,the basic line type and the parabolic curve-based temperature control curve function are selected,and analysis and verification are conducted through simulation and indoor experiments.The application analysis is carried out using a special high arch dam in southwest China as an example.The results show that the smooth temperature control curve reduces the large stress fluctuations caused by the conventional temperature control curve,and is more conducive to fully realizing the material properties under a reasonable line type.The concave temperature control curve has corresponding stress changes that are more consistent with the strength development rule,and the anti-cracking safety factor is stable during the process,making it the preferred curve.After optimizing the temperature control curve,the maximum stress under the same temperature condition is significantly reduced,reducing the risk of concrete cracking.Under the same safety coefficient condition,the highest temperature is effectively reduced,which can reduce the difficulty of temperature control and save temperature control costs.This research is of significant importance for the intelligent temperature control and anti-cracking of concrete dams.