寒区隧道衬砌周边冻胀力及防治措施研究

依托祁连山高寒区隧道工程进行衬砌周边冻胀力数值分析和防治措施研究,探究寒区隧道衬砌周边冻胀力分布规律。基于有限元软件,分析围岩性质、含水率和衬砌弹性模量对冻胀力的影响,以及针对性提出寒区隧道防冻措施。研究结果表明:隧道衬砌周边的冻胀力分布不匀,墙脚附近的冻胀力最大,仰拱中心处的冻胀力最小;围岩性质越差,衬砌周边冻胀力越小,围岩从Ⅳ级变化至Ⅵ级时,最大冻胀力从1.944 MPa减少至0.502 MPa;围岩与衬砌附近的含水率越高,作用在衬砌结构上的冻胀力就越大,当围岩中含水率从10%增加至30%时,最大冻胀力从1.672 MPa增至5.193 MPa;衬砌弹性模量越大,作用在衬砌上的冻胀力越强,弹性模量从8 GPa增至32 GPa时,最大冻胀力从0.878 MPa增至1.269 MPa。最后提出高寒区隧道衬砌抗冻病害设防等级和相应的措施建议,为高寒区隧道建设提供技术支撑。

Study on Frost Heaving Force Around Tunnel Lining in Cold Area and Prevention Measures

In order to further improve the prevention and control measures of tunnel frost heave in the cold region,this paper carried out numerical analysis of the frost heave force around the lining and studied the prevention and control measures.Based on the finite element software,the influence of the properties of surrounding rock,water content and elastic modulus of lining on frost heaving force was analyzed.The results show that the distribution of frost heaving force around the tunnel lining was apparently uneven.The frost heaving force was the maximum near the foot of the wall and the minimum at the center of the invert.With the surrounding rock properties became worse,the frost heave force around the lining became smaller.When the surrounding rock changed fromⅣtoⅥ,the maximum frost heave force decreased from 1.944 MPa to 0.502 MPa;With the water content of surrounding rock and lining became higher,the frost heaving force on lining structure became larger.When the water content of surrounding rock increased from 10%to 30%,the maximum frost heaving force increased from 1.672 MPa to 5.193 MPa;When the elastic modulus of lining increased from 8 GPa to 32 GPa,the maximum frost heaving force increased from 0.878 MPa to 1.269 MPa.Finally,in order to provide technical support for tunnel construction in high cold area,the level of frost resistance of tunnel lining and the corresponding measures were suggested.