考虑荷载修正的衬砌背后空洞对结构安全性影响分析

Analysis of Influence of Cavity Behind Lining on Structural Safety Based on Load Correction

以云南省某公路隧道为背景,建立考虑空洞影响下的荷载-结构修正计算模型,引入最小安全系数,对衬砌安全性进行评估。计算结果表明:背后存在空洞时,衬砌受力条件恶化,空洞处衬砌内力重分布明显,弯矩分布形态发生改变,导致衬砌安全性显著降低。拱顶或拱腰背后存在空洞时,衬砌最小安全系数均随空洞范围变大而降低。相同空洞范围下,相较于拱顶空洞,拱腰背后存在空洞时,衬砌最小安全系数更低。

Based on a highway tunnel in Yunnan Province,a load structure correction calculation model considering the effect of cavity is established,and minimum safety factor is used as index to evaluate the safety of lining.The results show that,when there is a cavity behind the lining,the stress condition of the lining deteriorates,the internal force of the lining in the cavity is redistributed obviously,and the distribution of moment changes,which leads to the decrease of lining safety.When there are cavities on one side of arch crown or arch waist,the minimum safety factor of lining decreases with the increase of cavity range.Compared with the vault cavity,the safety factor of arch waist cavity is worse under the same cavity range.