考虑围岩冻融损伤劣化效应的隧道长期稳定性研究

发布时间：2018-08-20 13:33

【摘要】：寒区隧道围岩受到冻融损伤劣化作用会对隧道长期稳定性造成不利影响。文章以鄂西北十房高速公路通省隧道片岩为例,通过室内冻融循环及压缩试验,得到单轴抗压强度与冻融循环次数之间的关系。根据掌子面围岩现场工程地质调查结果,并基于Hoek-Brown准则,估算出考虑冻融损伤劣化效应的岩体力学参数。然后采用FLAC3D对冻融循环条件下隧道的长期稳定性进行数值分析,分别得到0次、4次、8次、12次、16次、20次冻融循环条件下隧道衬砌位移场及应力场变化特征。结果表明,冻融循环作用下,隧道衬砌的变形及主应力均出现了不同程度的增大。与不考虑冻融损伤劣化作用相比,经过20次冻融循环作用后,衬砌的变形、最大主应力、最小主应力分别增大了1.3%、5.3%、1.5%。在支护方案选择及支护结构设计时,有必要考虑长期冻融循环作用下围岩力学特性损伤劣化对隧道稳定性的影响。
[Abstract]:The long-term stability of tunnel will be adversely affected by frost-thawing damage and deterioration of surrounding rock in cold region. Taking the schist of tunnel of Shifang Expressway in northwest Hubei Province as an example, the relationship between uniaxial compressive strength and freeze-thaw cycle times is obtained through indoor freeze-thaw cycle and compression tests. Based on the field engineering geological survey results of face surrounding rock and based on Hoek-Brown criterion, the mechanical parameters of rock mass considering the deterioration effect of freeze-thaw damage are estimated. Then, the long-term stability of tunnel under freeze-thaw cycle is analyzed by FLAC3D, and the variation characteristics of displacement field and stress field of tunnel lining under freezing and thawing cycle are obtained respectively under the conditions of 0 times, 4 times, 8 times, 12 times, 16 times, and 20 times, respectively. The results show that the deformation and principal stress of tunnel lining increase in varying degrees under the action of freeze-thaw cycle. Compared with those without freezing and thawing damage deterioration, after 20 freeze-thaw cycles, the deformation, maximum principal stress and minimum principal stress of the lining increased by 1.3% and 5.3% respectively. In the selection of supporting scheme and the design of supporting structure, it is necessary to consider the influence of damage deterioration of surrounding rock mechanical properties on tunnel stability under the action of long-term freeze-thaw cycle.
【作者单位】：武汉工程大学资源与土木工程学院;中国地质大学(武汉)工程学院;
【基金】：交通运输行业联合科技攻关项目(2010-353-342-260) 武汉工程大学教学研究项目(x2015026)
【分类号】：U451

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