Abstract: The article analyzes the process of filling water and heat preserving and pressure loading & unloading to the spiral case. Loading a pressure to the spiral case, the tension stress of steel plate increases; while unloading, total changing regulation of all instruments shows that the tensile stress decreased,and the joint between the spiral case and the concrete enlargeed,and the compressive stress of the perimetric concrete and steel bars increased.After unloading,the maximum joint took place in the cool seasons, and the minimum joint in the summer. Through analysis, we consider that the spiral case of left powerhouse units works normally, and that the stress and deformation are within the range of allowable design.

摘要： 本文对蜗壳充水保温加压及卸压过程进行了分析。加压后，钢板拉应力增大；卸压后各仪器总体变化规律表现为蜗壳拉应力减小，蜗壳与混凝土的缝隙增大，周边混凝土和钢筋压应力增大。卸压后缝隙最大开度出现在低温季节，最小开度出现在夏季。通过分析认为左厂房机组蜗壳工作性态正常，应力和变形均在设计允许范围内。