考虑随机裂隙的寒区隧道冻胀力研究

研究目的:为进一步研究围岩和衬砌结构的冻胀力,以2022年冬奥会重大交通保障项目金家庄特长螺旋隧道为依托,通过现场实测、室内试验和COMSOL数值模拟相结合的方法,探究考虑随机裂隙条件下,孔隙率、渗透率、随机裂隙孔径和模型下边界水头对冻胀力量值和分布规律的影响。研究结论:(1)衬砌结构的最大拉、压应力随孔隙率的增大而增大,随渗透率、随机裂隙孔径和下边界水头的增大而减小;(2)衬砌内、外边缘的第一主应力在拱腰处最大,内边缘第三主应力最大值位于拱脚处,而外边缘第三主应力量值由拱顶到仰拱逐渐降低;(3)围岩最大拉、压应力随着孔隙率和下边界水头的增大而增大,随着渗透率和随机裂隙孔径的增大而减小;(4)拱顶截线A的主应力量值及变化范围随孔隙率的增大而增大,随渗透率、随机裂隙孔径和下边界水头的增大而减小;(5)本研究结果可为寒区隧道冻胀力的量值大小和分布规律研究提供借鉴参考。

Research on the Frost Heaving Force of Tunnel in Cold Region with Random Cracks

Research purposes: To further study the frost heaving force of surrounding rock and lining structure,based on the 2022 Winter Olympics Games significant traffic security projects Jinjiazhuang extra-long spiral tunnel as the backing,through field test,indoor experiment and COMSOL numerical simulation,this paper studies the effects of porosity,permeability,random crack aperture and boundary water head under the model on frost heaving force and distribution.Research conclusions:( 1) The maximum tensile and compressive stresses of the lining structure increase with the increase of porosity and decrease with the increase of permeability,random crack aperture and lower boundary water head.( 2) The first principal stress on the inner and outer edges of lining is the largest at the arch waist,the third principal stress on the inner edge is the largest at the arch foot,and the third principal stress on the outer edge decreases gradually from the arch to the invert.( 3) The maximum tensile and compressive stresses of surrounding rock increase with the increase of porosity and lower boundary water head,and decrease with the increase of permeability and random crack aperture.( 4) The principal stress value and the variation range of transversal A of the arch increase with the increase of porosity,and decrease with the increase of permeability,random crack aperture and lower boundary water head.( 5) The research results can provide reference for the research on the magnitude and distribution of frost heaving force in cold tunnel.