A vertical-axis cylindrical steel tank for storing liquid NaOH failed as a result of large settlements of the sand and gravel foundation under its bottom. The tank had a ring-shaped reinforced concrete foundation under its shell, from which a large portion of rainwater would flow to under the tank bottom plates causing the settlement of the sand and gravel foundation. A local hollow, in which rainwater would periodically collect, appeared under the plates of the bottom. This was conducive to intensive corrosion of the plates in the region of the hollow. After 40 years of service a large local dent appeared in the tank’s bottom. Then as a result of intensive corrosion this part of the bottom was perforated and the liquid leaked out of the tank. After it was drained the tank underwent repairs as part of which a new foundation in the form of a reinforced concrete slab was made and the whole steel bottom was replaced. The settlements of sand and gravel foundations under the bottoms of cylindrical tanks for storing liquids are difficult to measure during the continuous operation of the tanks. Numerical analyses of the settlements of the subsoil and the vertical displacements of the bottom’s plates have shown the settlements to have a significant effect on the radial deformations of the tank’s shell in the zone of its contact with the bottom. It is proposed to periodically measure the radial displacements of the lower parts of liquid storage tanks’ shells to gain information about the potential failure hazard to the tanks due to the settlement of their foundations. Such measurements should be introduced as an obligatory element of monitoring the state of safety of each vertical-axis cylindrical steel tank over its whole service life.

垂直轴圆柱形钢制储罐用于储存液态NaOH，原因是其底部的沙子和砾石基础大量沉降。储水箱的外壳下方有一个环形的钢筋混凝土基础，大部分雨水从储水箱的底部流到储水箱的底部，导致沙子和碎石基础沉降。底部的板下方出现了一个局部空洞，雨水会定期收集在该空洞中。这有利于板在中空区域中的强烈腐蚀。使用40年后，油箱底部出现了较大的局部凹痕。然后，由于强烈腐蚀，底部的这一部分被打孔，液体从储罐中泄漏出来。排干水箱后，进行维修，其中一部分是钢筋混凝土板形式的新地基，并更换了整个钢制底部。在圆柱形储罐的底部连续运行期间，很难测量圆柱形储罐底部下方的沙子和砾石基础的沉降量。对地下土壤沉降和底板的垂直位移的数值分析表明，沉降对罐壳与底部接触的区域的径向变形具有重大影响。建议定期测量储液罐下部壳体的径向位移，以获取有关由于储罐基础沉降而对储罐造成潜在故障危险的信息。