大体积混凝土结构表面保温措施工程实例分析

Case study of insulation measures for the surface of mass concrete structure

为了避免某水电站坝体在施工和蓄水运行过程中因温度应力超过混凝土抗拉强度而产生裂缝,结合该大坝的实际工程情况,将大型商业有限元软件ANSYS与三维有限元温控主体程序RCTS相结合,对该水电站坝体在坝轴线方向横缝之间的整个坝段施工期和运行期的温度场、温度应力进行了仿真计算。计算结果表明:坝体基础常态混凝土垫层部位在外温变化及基岩约束双重作用下,出现了较大的拉应力。混凝土表面铺设保温板后,减小了外界温度对混凝土的影响,垫层部位的最大应力有所降低。可见,混凝土表面铺设保温板是降低温度应力的有效措施。

To prevent the dam of a hydropower station from cracking due to temperature stress larger than concrete tensile strength during dam construction and impoundment, this paper, based on the actual operation conditions of the dam and by combining the large commer- cial FEM software ANSYS with the 3D FEM temperature control programe RCTS, carries out simulation calculation of the temperature field and stress of the whole dam block between the latitudinal joints along the dam axis direction in the construction and operation periods. The calculation result shows that the normal concrete cushion of dam foundation has great tensile stress under the double action of external temperature change and bedrock constraints. The insulation boards laid over the concrete surface reduce the influence of external temperature on the concrete and the maximum stress of the cushion drops in some degree. Therefore, the effective measure to reduce temperature stress is to lay insulation boards over the concrete surface.