考虑热学参数空间变异性的重力坝施工期温度及应力场分析

An Analysis of the Temperature and Stress Field in the Gravity Dam Considering the Spatial Variability of Thermal Parameters During the Construction Period

碾压混凝土坝的温控防裂一直是工程建设中的关键技术问题。由于浇筑仓面大、碾压质量不均匀以及混凝土的非均质性,碾压混凝土坝材料参数具有显著空间变异性。传统混凝土坝温度与应力分析常采用确定性计算,忽略了参数空间变异的影响,导致温度及应力场模拟不够合理。本文基于随机场理论和中心点离散方法,提出了混凝土热学参数空间变异有限元模拟方法。TJ大坝案例分析表明,考虑热学参数空间变异后,最高温度场和最大拉应力场在平均效应上与确定性结果基本一致,热学参数空间变异显著影响大坝混凝土结构的最高温度和最大应力。随机温度应力场下结构部分位置温度及应力超过了允许值,意味着依据传统确定性温度应力分析结果提出的温控措施可能偏危险。提出的随机温度应力分析方法对重力坝施工期温控措施的制定提供了方法支持。

Temperature control and crack prevention of roller-compacted concrete(RCC) dams are the key technical problems in the construction of projects. The material parameters of RCC dams have significant spatial variability due to the large pouring concrete surface, uneven rolling quality, and heterogeneity of concrete. The deterministic calculation is adopted in the traditional temperature and stress analysis of concrete dams,which ignores the influence of parameter spatial variability, resulting in unreasonable simulation of temperature and stress field. Based on the random field theory and the center point discrete method, a finite element simulation method of spatial variability of concrete thermal parameters is proposed in this paper. The case study of TJ dam shows that the average effect of the maximum temperature field and maximum tensile stress field considering the spatial variability of thermal parameters is basically consistent with the deterministic results.The spatial variability of thermal parameters significantly affects the maximum temperature and maximum stress of the dam concrete structure. The temperature and stress at some positions of structures in the random temperature and stress field exceed the allowable value, which means that the temperature control measures proposed based on the traditional deterministic temperature stress analysis results may be dangerous. The random temperature and stress analysis method proposed in this paper provides methodological support for the formulation of temperature control measures of gravity dams during the construction period.