[提要]  大型机组的汽轮发电机基座底板尺寸都较大，属于大体积砼，施工浇筑砼后，将产生大量水化热，致使基座底板升温和膨胀。降温时，由于地基约束作用，底板砼将产生收缩应力，当收缩应力大于砼抗拉强度时，底板产生贯穿性裂缝。本文论述了为避免贯穿性裂缝的出现，建议设计时应进行施工时砼抗裂性验算，并提出了验算的方法。
[关键词]  汽机基座底板 砼水化热 温度收缩应力 贯穿性裂缝 抗裂性验算

The bottom slab of the foundation of the large scale turboge-nerating unit, which dimentions are large, is a large volume concrete, It produces significant quantities of hydration heat after the concrete was placed, which made the temperature of the foundation risen and the foundation expanded. When temperature reduced, the concrete of the bottom slab will produce shrinking stress because of the restraint of the subsiol. The bottom slab will produce penetrating cracks if the shrinking stress is larger than the tensile strenth of the concrete.ln order to prevent the penetrating cracks in constrution a way of checking computation is given.
Keywords: bottom slab;foundation of the turbogenerator; hydration heat; shrinking stress; penetrating
cracks; ability of resisting cracks; concrete