季节冻土区衬砌渠道换填措施防冻胀数值模拟

Numerical simulation of anti-frozen heave by replace-filling measures for lined canal in seasonal frozen soil region

为了防治季节冻土区衬砌渠道的冻胀破坏，对渠基易冻胀土体进行换填的防冻胀措施效果进行研究，考虑实际边界条件，建立浅层冻土相变温度场数学模型，应用有限元软件对沈阳市浑北灌区渠道进行不同换填深度的热力耦合分析，结果表明：渠道阴坡、渠底、阳坡表面下1．670 m、1．128 m、1．547 m处为冻融活动区；换填厚度与冻深近似呈正比关系；随着换填深度的增加，砼衬砌渠道的法向冻胀量减少；渠道阴坡、阳坡及渠底的换填率分别为53．9％、58．2％、79．8％时，砼衬砌板的法向位移分别减少96．9％、95．54％、96．83％；法向位移0．6～0．7 cm，在规范允许值（0．5～1．0 cm）内，有效地消减了渠道的冻胀破坏，可为工程换填优化设计提供理论参考。

In order to prevent the frost heave damage to lined channel in seasonal frozen soil region,carried out the research on the effect of anti-frozen heave measures by replacing frost heave sensitive soil in canal base .Considered the actual boundary condition,set up the mathematical model of phase transition temperature field in shallow frozen soil . Carried out the coupled heat-stress analysis of different filling depths by using FEM.The results revealed that：Under the ground of shady canal slope,canal bottom and surface of sunny slope at 1 .670 m,1 .128 m and 1 .547 m,here,was the active zone of freezing and thawing .The replacing soil depth closely was submited a positive correlations with the frozen depth .It also shown that with increasing the replacement depth,the normal vitical frozen heave of the concrete lined channel will be reduced .When the replace-filling rates in channel shady slope,bottom and sunny slope were 53 .9%, 58 .2%and 79 .8%respectively,the normal displacements of concrete lining were decreased by 96 .9%,95 .54%and 96 .83%.Also the normal displacement was 0 .6~0 .7 cm which was remained within the standar accepted value as 0 .5~1 .0 cm .This measures can be effectively alleviated the frozen heave damage of channels and provided a theoretic ref-erence for optimal design of the replace-filling in engineering practices .