基于光纤观测数据的特高拱坝孔口温度开裂风险评估研究

Due to long construction period of super high arch dam, high pouring quality is required. The first job of quality control during construction is temperature control and crack prevention. The orifice is the key part of arch dam that is easy to crack during the construction period. Therefore, it is necessary to track changes in the material properties of concrete, and evaluate the orifice cracking risk of arch dam.. To solve this problem, field monitoring and numerical simulation are adopted. Firstly, thermal parameters and mechanical parameters of orifice are inversed jointly based on the distributed optical fiber observation data and particle swarm optimization. The law of changes of material parameters and the change of thermal stress is clarified. Secondly, real-time perception of dynamic process of concrete pouring, temperature control and crack prevention is conducted. Thermal stress and cracking risk of orifice during the construction period are analysed to realize dynamic feedback of temperature control measures and cracking risk. Finally, the refinement computational model of orifice group of arch dam based on the octree regular mesh generation technology is established for the stress distribution analysis of dam and cracking stability of orifice during the operation period. Thus temperature cracking risk analysis of the orifice in the construction and operation period has implemented. It provides theoretical supports for the safety evaluation of arch dam.

特高拱坝施工周期长，浇筑质量要求高，温度控制与防裂是施工期质量控制的首要任务。孔口是拱坝施工期较易开裂的重点部位，有必要实时跟踪混凝土材料特性变化规律，对孔口开裂风险进行评估。. 本项目围绕拱坝孔口部位，拟从现场监测和数值模拟方法进行研究。首先基于分布式光纤观测数据和粒子群算法，对混凝土施工期热学与力学参数进行联合反演，阐明材料参数与温度应力性状变化之间规律；其次实时感知混凝土浇筑与温控防裂动态历程，进行孔口施工期温度应力和开裂风险分析，实现温控措施和开裂风险动态反馈；最后基于八叉树规则网格剖分技术，建立拱坝孔口群精细化计算模型，复核大坝运行期应力分布并对孔口进行开裂稳定性分析。从而实现孔口施工期和运行期温度开裂风险分析，为特高拱坝安全评价提供一定的理论支撑。

特高拱坝施工周期长，浇筑质量要求高，温控防裂是施工期质量控制的首要任务。孔口是施工期较易开裂的重点部位，需实时掌握其温度场变化，从而跟踪混凝土热学特性变化规律，对孔口开裂风险进行评估。. 本项目围绕拱坝孔口部位，从现场监测和数值模拟方法进行研究。首先，基于分布式光纤，对高温季节底孔和低温季节深孔浇筑进行温度监测，获取不同部位温度变化过程；其次，基于分布式光纤测温数据和粒子群算法，对混凝土施工期热学参数进行反演分析，阐明热学参数与温度变化之间规律；最后，考虑孔口结构形式、材料特性、浇筑历程和边界属性影响，构建孔口施工过程局部仿真模型，计算孔口施工期温度，实现温控措施和开裂风险动态反馈。研究成果可为特高拱坝温控防裂与安全评价提供一定的理论支撑。