基础局部沉陷下大型储罐变形形态与应力分析

大型钢制储罐是一种地基沉降十分敏感的特种结构,尤以沿罐周的不均匀沉降即基础局部沉陷对罐体的影响最为关键。本文采用有限元方法,研究分析了大型钢制储罐沿罐周相邻点不均匀沉降达到临界值的情况下,钢储罐的变形形态以及其应力分布特征。结果表明,在基础局部沉陷情况下,储罐的变形形态表现为褶皱式扭曲凹凸,具谐波状特征;罐壁内最大Mises应力点对浮顶罐主要发生在罐壁的中下部,对拱顶罐主要发生在罐壁底部。结果同时也表明,基础局部沉陷对浮顶罐的危害影响主要为浮盘的升降困难,对拱顶罐为罐底部局部应力的加剧。

Analysis of Deformation Form and Stress for Large Storage Tank under the Local Subsidence of Foundation

The large steel storage tank is special sensitive to subgrade settlement, and the differential settlement along the tank perimeter, i. e local subsidence of foundation, is the key factor to affect tank body. In this paper, the FEM is used for the study of deformation shape and stress distribution in tank shell of large storage tank under the dif- ferential settlement in adjacent monitoring point along the tank perimeter approaching to crtical value. The results indi- cated that deformation shape of tank is concavo-convex distortion in draping having character of hamonious wave ; max Mises stress in tank shell occurs middle-low part of tank for floating tank, and at bottom of tank for fixed roof tank. The results also indicated that the harmful effect for floating tank under the local subsidence of foundation is mainly to make floating cabin lift difficult, to aggravate stress concentration at the bottom of tank shell for fix roof tank.