日照强热辐射对西藏大古水电站碾压混凝土重力坝的影响分析

Influence of sunlight strong heat radiation on RCC gravity dam of Dagu Hydropower Station in Tibet

大古水电站位于西藏高寒高海拔地区,坝址区日照辐射强烈,显著影响了环境温差的变化,加剧了施工期乃至运行期大坝结构温度场时空分布的不均匀性,增加开裂风险。选取大古水电站14号厂房坝段为研究对象,采用三维有限元法对大坝施工期温度场和温度应力进行数值模拟仿真计算,分析了日照强热辐射对大坝的影响。结果表明:日照强热辐射在坝体表面产生了约0.6 MPa的拉应力,拉应力区影响深度在0.6 m范围内;采取混凝土表面保温防护措施后,拉应力减少至约0.1 MPa,有效降低了混凝土开裂风险。

Dagu hydropower station is located in the high cold and high altitude area of Tibet.The sunshine radiation in the dam site area has a strong impact on the change of environmental temperature difference,which aggravates the uneven distribution of temperature field in the construction period and even operation period,and increases the risk of cracking.The No.14 plant dam section is selected as the research object.The three-dimensional finite element method is used to simulate the temperature field and temperature stress during the construction period of the dam,and the influence of the strong heat radiation of sunshine on the dam is analyzed.The results show that the tensile stress of the dam surface is about 0.6MPa,and the influence depth of the tensile stress area is within 0.6m.After taking the thermal insulation protection measures on the concrete surface,the tensile stress decreases to about 0.1 MPa,which effectively reduces the risk of concrete cracking.