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[提要]  大型機(jī)組的汽輪發(fā)電機(jī)基座底板尺寸都較大，屬于大體積砼，施工澆筑砼后，將產(chǎn)生大量水化熱，致使基座底板升溫和膨脹。降溫時(shí)，由于地基約束作用，底板砼將產(chǎn)生收縮應(yīng)力，當(dāng)收縮應(yīng)力大于砼抗拉強(qiáng)度時(shí)，底板產(chǎn)生貫穿性裂縫。本文論述了為避免貫穿性裂縫的出現(xiàn)，建議設(shè)計(jì)時(shí)應(yīng)進(jìn)行施工時(shí)砼抗裂性驗(yàn)算，并提出了驗(yàn)算的方法。
[關(guān)鍵詞]  汽機(jī)基座底板 砼水化熱 溫度收縮應(yīng)力 貫穿性裂縫 抗裂性驗(yàn)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