拱坝低热水泥混凝土抗裂效果仿真

Simulation of crack resistance effect of low heat cement concrete for arch dams

为了研究低热水泥混凝土在白鹤滩大坝中的抗裂效果,对比了低热硅酸盐水泥混凝土和常规中热水泥混凝土的热力学性能,并在典型坝段上设计温控方案。通过有限元仿真计算温度和应力,分析比较了两者在早期、一期冷却、二期冷却及封拱后等关键时段的温度、应力以及表面抗裂效果。结果表明,不同季节浇筑的混凝土应力过程线趋势一致。相比中热混凝土,低热混凝土在各不同时期均具有更高的抗裂安全系数,温控防裂的重点仍在二期冷却末。对于昼夜温差大的情况,低热水泥在早龄期需要更好的保温措施来达到表面抗裂效果。

To investigate the crack resistance effect of low-heat cement concrete in the Baihetan Dam,the thermodynamic performances of low-heat cement concrete and regular medium hot cement were compared,and the temperature control scheme was designed on a typical dam section.The temperature and stress were calculated by finite element simulation,and their effects on temperature,stress and surface crack resistance were analyzed and compared in the critical periods of early cooling,primary cooling,secondary cooling and arch sealing.The results show that the stress process trend of concrete is consistent in different seasons.Compared with medium hot concrete,low-heat cement concrete has higher safety factor of crack resistance,but the key point of temperature control and crack prevention is still at the end of the secondary cooling.In addition,for the case of large temperature difference between day and night,the low-heat cement needs better insulation measures at the early age to achieve the surface anti-cracking effect.