大跨度傍山棚洞衬砌结构安全性分析

Safety Analysis on Lining Structure of Long-Span Shed-Tunnel alongside Mountain

运用荷载结构法,计算棚洞三维衬砌结构各单元的内力值,并根据其衬砌结构的配筋情况进行安全性计算。数值模拟表明:棚洞衬砌结构的最大轴力出现在靠山侧边墙墙脚位置,最大负弯矩出现在曲墙中央区域,最大正弯矩出现在左顶板中央区域;跨中处断面衬砌结构的安全系数较柱顶支座处断面衬砌结构的安全系数略高,整个衬砌结构的安全系数满足相关JTGD70—2004《公路隧道设计规范》要求。

The plane analysis is mainly used in previous finite element analysis of shed-tunnel＇ s structure. Although the plane analysis is simple, they cannot analyze the safety of lining structure at cross-section of span. The load structure meth- od is applied to calculate the internal force of each element in 3-D shed-tunnel lining structure, furthermore, the safety cal- cnlations is also carried out according to its lining structure reinforcement. The numerical simulation shows that the maxi- mum axial force of shed-tunnel lining appears in the sidewall of the foundation along the mountain; the maximum positive moment appears in the central region of curved wall and that most positive moment appears in the central region of the left board. The lining structure safety coefficients of mid-span section are slightly higher than those of the support saddle sec- tion, and the safety coefficients of whole lining structure satisfy the requirements of ＂Road and Tunnel Design Specification＂ （JTG D 70--2004）.