冻融循环和不均匀冻胀下寒区隧道的塑性解答  

PLASTIC SOLUTIONS OF A COLD REGION TUNNEL UNDER FREEZE-THAW CYCLES AND NON-UNIFORM FROST HEAVE

作　　者：张常光[1,2] 高本贤 周渭 李海祥 Zhang Changguang;Gao Benxian;Zhou Wei;Li Haixiang(School of Civil Engineering,Chang'an University,Xi'an 710061,China;Stake Key Laboratory of Geohazard Prevetion and Geoenvironment Protection,Chengdu 610059,China;School of Highway,Chang'an University^Xi'an 710064,China)

机构地区：[1]长安大学建筑工程学院,西安710061 [2]地质灾害防治与地质环境保护国家重点实验室,成都610059 [3]长安大学公路学院,西安710064

出　　处：《力学学报》2022年第1期252-262,共11页Chinese Journal of Theoretical and Applied Mechanics

基　　金：国家自然科学基金(41202191);地质灾害防治与地质环境保护国家重点实验室开放基金(SKLGP2020K022);长安大学中央高校基本科研业务费专项资金(300102280108)资助项目。

摘　　要：季冻区长期冻融循环造成围岩强度和变形性能劣化,使得寒区隧道易进入塑性状态,且寒区隧道围岩呈现以径向冻胀为主的不均匀冻胀.合理考虑寒区隧道冻融循环对围岩性能的劣化以及围岩的不均匀冻胀属性,基于Mohr-Coulomb准则推导了寒区隧道冻胀力、应力与位移的塑性解答,同时给出相应的弹性解答和冻结围岩弹-塑性状态的判定方法,对所得解答进行讨论和对比验证,最后探讨了冻融循环、不均匀冻胀与体积冻胀率对寒区隧道应力分布、塑性区半径、洞壁位移和冻胀力的影响规律.研究表明:本文解答具有广泛的适用性和良好的可比性,并得到文献塑性解答的退化验证;冻胀力、洞壁位移与塑性区半径随冻融次数增加分别增大20.3%、8.44倍、2.16倍,以量化长期冻融循环造成围岩性能的劣化效应;冻结围岩由均匀冻胀转变为不均匀冻胀时冻胀力增大42.8%,但塑性区半径几乎无变化;4种体积冻胀率参数均显著影响冻胀力,尤其是水热迁移系数可使冻胀力增大123.6%.本文结果可为季冻区隧道设计与冻害问题解决提供一定的理论依据.Long-term freeze-thaw cycles of the seasonal cold region result in the deterioration of strength and deformation properties of surrounding rock, which make cold region tunnels easily reach a plastic state, and surrounding rock of a cold region tunnel displays the non-uniform frost heave mainly in radial direction. Based on the Mohr-Coulomb criterion, plastic solutions of the frost heaving force, stress and displacement for a cold region tunnel were presented. The proposed solution reasonably accounts for the deterioration of surrounding rock properties caused by freeze-thaw cycles and the non-uniform frost heave of surrounding rock. Meanwhile, the corresponding elastic solutions and a means to determine the elasto-plastic state of frozen surrounding rock were introduced. Furthermore, discussions and comparative verifications of the proposed solution were performed. Finally, the effects of freezing-thawing cycles, the non-uniform frost heave and volumetric frost heave ratio on stress distribution, plastic zone radius, wall displacement and frost heave force of cold region tunnels were investigated. It is indicated herein that the proposed solution has broad applicability and decent comparability, which is partly demonstrated by a plastic solution available in the reference. With increasing the number of freeze-thaw cycles, the frost heave force, wall displacement and plastic zone radius are increased by 20.3%,8.44 times, and 2.16 times, respectively. It quantifies the deterioration effect of surrounding rock properties caused by long-term freeze-thaw cycles. When frozen surrounding rock is frost heaved from a uniform model to a non-uniform one,the frost heave force is increased by 42.8%, yet the radius of plastic zone is almost unchanged. Four parameters of volumetric frost heave ratio significantly affect the frost heave force, peculiarly the water-heat migration factor which leads to the increase of the frost heave force by 123.6%. The results of this study can provide some theoretical basis for the design and f

关 键 词：寒区隧道 塑性解答 冻融循环 不均匀冻胀 体积冻胀率 

分 类 号：TU457[建筑科学—岩土工程]