坝体保温层的等效模拟及保温效果分析

Equivalent simulation of dam heat insulators and their effect analysis

针对目前保温层设计施工中工程经验占主导而数值仿真研究相对较少的情况,基于大型商业有限元分析软件ABAQUS,对某工程保温层进行有限元分析计算。采用参数等效算法,在同一模型上计算不同厚度(1.5 cm,2.5 cm,5.0 cm)保温层防护下的坝体温度场及应力场。分析结果表明:①统计特征点在无保温层时的年内温差较大;铺设保温层后,年内温度变幅显著降低;保温效果随着保温层厚度的增大而逐渐增强;铺设5.0 cm厚的聚苯板保温层可将统计特征点的年内最大温差由15.47℃减小为6.30℃。②在无保温层保护的情况下,下游坝面出现大面积的拉应力区,最大拉应力值超出混凝土的抗拉强度;增加保温层后,坝体下游面应力状况得到明显改善,拉应力区减小且拉应力值随保温层厚度的增加而逐渐减小;铺设5.0 cm厚的聚苯板保温层可将拉应力值由未加保温层时的2.73MPa减小为1.46MPa。

In consideration of the fact that the current design and construction of heat insulators were mainly dominated by project experiences but rarely depended on numerical simulation, an analysis was perfomed on the heat insulator of a dam by use of the finite element method based on ABAQUS. Parameter equivalence algorithm was used to calculate the temperature field as well as the stress field of the dam coveted by different thickness （1.5cm, 2.5cm, and 5,0cm） of heat insulators. Some conclusions were drawn as follows： the temperature at representative points varied obviously during a year when no insulator was laid, while the range of temperature variation during a year decreased significantly under the protection of a heat insulator; the effect of the heat insulafion improved with the increase of the thickness of the heat insulator, and the maximum temperature difference at the representative points during a year decreased from 15,47℃ to 6.30 ℃ under the protection of 5.0cm polystyrene insulator; a tensle stress zone of large area appeared on the downstream surface of the dam when no heat insulator was laid, and the maximum tensile stress was larger than the tensile strength of concrete, while the stress zone decreased under the protection of the heat insulator, the tensile stress decreased with increase of the thickness of the heat insulator, and the maximum tensile stress decreased from 2.73MPa to 1.46MPa under the protection of 5.0cm polystyrene insulator.