考虑冻融作用的混凝土拱坝结构可靠度分析  

Structural Reliability Analysis of Concrete Arch Dam Under Freeze-thaw Effect

作　　者：蔡荨[1,2] 杨妙帆 周克发 CAI Qian;YANG Miao-fan;ZHOU Ke-fa(Nanjing Hydraulic Research Institute,Nanjing 210029,China;State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering,Nanjing 210029,China;MCC Huatian Nanjing Engineering Technology Corporation,Nanjing 210029,China)

机构地区：[1]南京水利科学研究院,江苏南京210029 [2]水文水资源与水利工程科学国家重点实验室,江苏南京210029 [3]中冶华天南京工程技术有限公司,江苏南京210029

出　　处：《水电能源科学》2021年第4期76-79,189,共5页Water Resources and Power

基　　金：国家重点研发计划(2018YFC0407104);中央级科研院所基本业务费项目(Y719010)。

摘　　要：混凝土拱坝在长期运行过程中,坝体材料受冻融作用易产生劣化效应,影响其结构可靠性和服役寿命。但目前考虑材料劣化作用的拱坝安全性态分析研究较少,不利于拱坝工程长效安全运行。对此,基于实测数据建立了混凝土材料力学性能冻融劣化模型,分析温度荷载、水荷载及材料强度等因素的不确定性,结合某混凝土拱坝实际工程,基于有限元等效应力法与一种改进收敛准则的响应面法,研究了冻融作用下拱坝结构可靠度时变过程。结果表明,随着劣化程度加深,受坝体材料"变软"影响,拱坝结构可靠度初期略微提升,后由于材料强度降低可靠度迅速降低,最终趋于平稳。多年运行后混凝土拱坝结构相对脆弱,日常运行中对两岸拱端等薄弱部位应加强监测与维护。During the long-term service of concrete arch dam,the material of the dam body is liable to deteriorate under freeze-thaw action,which could impair the structural reliability and cut down its service life.However,there are currently few studies on the safety state analysis of arch dams considering material deterioration,which is not conducive to the long-term safe operation of arch dam projects.In this paper,the freeze-thaw deterioration model of mechanical properties of concrete was established based on the measured data.The uncertainties of temperature load,water load and material strength were analyzed.Based on a real concrete arch dam project,the time-varying process of the structural reliability of arch dam under freeze-thaw action was studied through finite element equivalent stress method and a response surface method with an improved convergence criteria.The results show that as the degree of deterioration increases,affected by the "softening" of dam material,the reliability is improved slightly at the beginning,but later decreases rapidly due to the decrease of material strength and is stabilized eventually.After years of operation,the structure of concrete arch dam becomes relatively fragile.In the daily operation,the monitoring and maintenance should be strengthened for the weak parts such as the arch abutment.

关 键 词：冻融 混凝土拱坝 劣化模型 可靠度 响应面法 

分 类 号：TV37[水利工程—水工结构工程]