楼板变形对地下大空间外墙结构设计的影响分析

Analysis on Impact of Floor Deformation on Design of External Wall in Large Underground Space Structure

在地下空间结构中,外墙设计是否合理直接影响工程造价及结构安全.在构建整体模型中,通常假定地下大空间楼板为平面内无限刚.但对于楼板存在边跨开洞、不连续、板墙刚度比较小等情况,外墙与楼板连接处仍采用铰接则不符合板墙实际受力.在实际工程中,当楼板平面内刚度相比外墙抗弯度较小时,深埋地下结构外墙的跨中弯曲变形及支撑薄板平面内变形较大,会引起外墙内力的重分布,若不考虑则会引起较大的计算误差.因此在板墙计算分析时,结构外墙的边界条件实际为刚度变化的弹簧支座,在设计上应依据有限元计算结果采用相应的加固措施.基于日照综合客运站北广场地下空间建筑工程对地下室外墙进行有限元计算,提出深埋大空间结构外墙结构设计优化方案.

In the underground space structure,the rationality of the external wall design will directly affect the engineering cost and structural safety.In building the overall model,it is usually assumed that the large underground space slab is infinite rigid in the plane.But for these situations,such as floor slab with side span opening,discontinuities slab,smaller stiffness ratio of wall and slab,the articulation still used at the connection of external wall and floor slab does not conform to the practical stress of slab wall.If the in-plane stiffness of floor slab is smaller than the bending resistance of the external wall in practical engineering,the mid span bending deformation of the external wall in the underground structure and the in-plane deformation of support plates are larger,which will lead to the internal force redistribution of the external wall.In case not considering,the larger calculation error will be caused.Therefore,when the plate wall is calculated and analyzed,the boundary condition of the external wall is actually a spring support with stiffness variation.In the design,the corresponding reinforcement measures should be taken according to the results of finite element calculation.Based on the underground space construction project in the north square of Rizhao Integrated Passenger Station,the finite element calculation is carried out for its external wall.The optimization design scheme of exterior wall structure for deep buried large space structure is put forward.