斜风作用下季冻区隧道冻胀力分布规律及结构安全性评价

为分析不均匀冻胀荷载对季冻区隧道结构受力及安全性的影响，本文依托某新建铁路隧道工程，在凝练工程区气象特征的基础上，利用数值模拟手段分析了斜风作用下隧道温度场的分布特征，解析得到了支护结构的冻胀力荷载，在此基础上分析了支护结构的受力特征并开展了安全性评价。研究结果表明：斜风作用下隧道较小进深范围内迎风侧与背风侧温度场存在差异，进深10m处差异最为显著；未铺设保温层条件下迎风侧围岩冻结深度约为背风侧的1.8倍，铺设保温层后迎风侧围岩冻结深度减小了约80%，背风侧围岩冻结区基本消失；围岩冻结深度不一致导致冻胀力荷载不均匀分布，冻胀力荷载作用下支护结构迎风侧的应力、轴力、弯矩均明显高于背风侧；未铺设保温层条件下仅仰拱区域符合安全性要求，铺设保温层后各区域均满足要求，但迎风侧安全性明显低于背风侧。

Distribution law of frost heave force and structural safety evaluation of tunnel in seasonally frozen area under oblique wind

In order to analyze the influence of uneven frost heave load on the stress and safety of tunnel structure in seasonal freezing area, this paper relies on a new railway tunnel project, and on the basis of condensing the meteorological characteristics of the engineering area, the distribution characteristics of tunnel temperature field under oblique wind are analyzed by numerical simulation. The frost heaving load of the support structure is obtained by analytical method, and the stress characteristics and safety of the support structure are analyzed on this basis. The results show that there are differences in the temperature field between the windward side and the leeward side within a small depth range of the tunnel under the oblique wind, and the difference is the most significant at the depth of 10m. Without the insulation layer, the freezing depth of the surrounding rock on the windward side is about 1.8 times that of the leeward side, Under the condition of laying insulation layer, the freezing depth of surrounding rock on the windward side is reduced by about 80%, the frozen area of surrounding rock on the leeward side basically disappeared. Inconsistent freezing depth of surrounding rock leads to uneven distribution of frost heave load, under the frost heave load, the stress, axial force and bending moment on the windward side of the supporting structure are significantly higher than those on the leeward side.Under the condition that no insulation layer is laid, only the inverted arch area meets the safety requirements. After the insulation layer is laid, all areas meet the requirements, but the safety of the windward side is significantly lower than that of the leeward side.