考虑流变效应的软岩大变形隧道多层支护作用机理分析
Analysis on Action Mechanism of Multi-layer Support in Soft Rock Large Deformation Tunnels with Consideration of Rheological Effects
朱建林 1王立川 2刘志强 1马利遥 2李庆斌3
作者信息
- 1. 中铁西南科学研究院有限公司,成都 611731
- 2. 中铁十八局集团有限公司,天津 300222;中南大学土木工程学院,长沙 410075
- 3. 中铁十八局集团有限公司,天津 300222
- 折叠
摘要
为了更好地描述软岩大变形隧道多层支护作用下围岩的流变特性,假定围岩本构模型为黏弹-塑性流变模型,塑性屈服准则选用Mohr-Coulomb屈服准则,将多层支护作用简化为分时分次施加不同大小的恒定支护力,推导多层支护作用下围岩位移的解析解.通过与有限差分数值解进行对比分析,得到两种方法的围岩位移随时间变化规律基本一致的结论,验证了解析解的合理性.通过具体算例,分析多层支护对围岩应力场、位移场的影响.研究结果表明:(1)隧道开挖同时施加的第一层支护力产生的围岩位移与围岩的黏弹-塑性效应有关,后续施加的支护力产生的位移增量仅与围岩的黏弹性效应有关;(2)随着时间的推移和多层支护作用下围岩洞壁支护反力的增加,围岩塑性区与黏弹性区交界面切向应力逐渐减小;(3)围岩径向位移从洞壁到围岩深处呈递减趋势分布,随着时间的增加,位移逐渐增大,直至变形稳定.
Abstract
In order to better describe the rheological characteristics of surrounding rock under multi-layer support in soft rock tunnel with large deformation,the constitutive model of surrounding rock is assumed to be a viscoelastic-plastic rheological model,and the plastic yield criterion is selected as the Mohr-Coulomb yield criterion.The multi-layer support is simplified as applying different constant support forces at different times.The analytical solution of the displacement of surrounding rock under multi-layer support is derived.By comparing and analyzing with the finite difference numerical solution,it is concluded that the displacement of surrounding rock over time obtained by the two methods is basically consistent,verifying the rationality of the analytical solution.Through specific examples,the influence of multi-layer support on the stress field and displacement field of surrounding rock is analyzed.The research results show that:(1)The displacement of surrounding rock caused by the first-layer support force applied simultaneously with tunnel excavation is related to the viscoelastic-plastic effect of surrounding rock,and the incre-mental displacement caused by subsequently applied support forces is only related to the viscoelastic effect of sur-rounding rock;(2)With the increase of time and the increase of the support reaction force on the tunnel wall under multi-layer support,the tangential stress at the interface between the plastic zone and the viscoelastic zone of sur-rounding rock gradually decreases;(3)The radial displacement of surrounding rock shows a decreasing trend from the tunnel sidewall to the depth of surrounding rock,and increases with time until the deformation stabilizes.
关键词
软岩大变形隧道/流变效应/多层支护/围岩位移/围岩应力Key words
Soft rock tunnel with large deformation/Rheological effects/Multi-layer support/Surrounding rock dis-placement/Surrounding rock stress引用本文复制引用
基金项目
中铁十八局集团有限公司科技研究开发计划课题(G23-02-S)
出版年
2024
NETL
NSTL
万方数据