考虑冻融循环效应的非静水压寒区隧道应力场弹性分析

Elastic Analysis of Tunnel Stress Field in Cold Zone Under Non-Hydrostatic Pressure Considering Freeze-Thaw Cycle Effect

为综合研究冻融循环和非静水压力共同作用下寒区隧道应力分布的规律,考虑寒区隧道冻结围岩的不均匀冻胀特性和冻融循环对围岩力学性能的影响,基于复变函数方法,建立非静水压力作用下寒区隧道冻融圈整体冻胀模型,推导非静水压力作用下寒区隧道应力的弹性解答,对所得解进行对比验证和参数分析,讨论冻融循环次数、不均匀冻胀系数、侧压力系数、冻胀率等因素对寒区隧道应力的影响规律。结果表明:1)冻胀力随冻融循环次数、不均匀冻胀系数的增加分别增大了89%、26.7%。2)侧压力系数λ对冻胀力有着显著影响,当λ≥1时,冻胀力随方位角的增大而增加;当λ<1时,冻胀力随方位角的增加而减小。3)4种体积冻胀率参数中对冻胀力影响最大的是水热迁移系数,可使冻胀力增大36.4%。

To comprehensively investigate the stress distribution patterns of tunnels in cold zone under the joint action of freeze-thaw cycle and non-hydrostatic pressure,an overall frost heave model of freeze-thaw cycle of tunnels in cold zone under non-hydrostatic pressure is established based on compound function considering the inhomogeneous frostheave characteristics of the frozen surrounding rocks of the tunnels in cold zone and the influence of freeze-thaw cycle on the mechanical properties of the surrounding rocks.Then the elastic solution of the stress of the tunnels in cold zone under the action of non-hydrostatic pressure is deduced,and a comparative validation and parametric analysis are conducted on the obtained solution.Finally,the influence of the number of freeze-thaw cycles,inhomogeneous frostheave coefficient,lateral pressure coefficient,freezing and expansion rate on the stress of tunnels in the cold zone is discussed.The results reveal the following:(1)The frost-heave force increases by 89%and 26.7%with increasing number of freeze-thaw cycles and inhomogeneous frost-heave coefficient,respectively.(2)The lateral pressure coefficientλhas a considerable impact on the frost-heave force,the frost-heave force increases and decreases with increasing azimuthal angle whenλ≥1 andλ<1,respectively.(3)The hydrothermal migration coefficient considerably affects the frost-heave force rather than other three volumetric freezing and expansion rate parameters,which can increase the frost-heave force by 36.4%.