流变效应作用下高地应力铁路软岩隧道衬砌结构长期稳定性研究

高地应力软岩具有变形量大、变形速率快、持续时间长、流变性强等特点,围岩流变性对衬砌结构长期稳定性影响大。以木寨岭铁路隧道为例,结合室内蠕变试验结果,采用Burgers流变模型,分析不同流变周期内支护结构受力随时间变化的规律。结果表明:(1)本文采用的Burgers模型能较好地反映围岩流变特性;(2)目前木寨岭隧道的支护结构形式,已施作的衬砌结构在以后数年发生压溃开裂的风险较大;(3)提高支护结构的长期稳定性及安全性,应从改变围岩流变性的角度出发,降低围岩的流变特性,增强围岩强度。

Study on Long Term Stability of Tunnel Lining Structure in High Stress Soft Rock Tunnel under the Effect of Rheology

High stress soft rock has the characteristics of great deformation,fast deformation rate,long duration and strong rheological property.The surrounding rock of rheological property has great influence on the long-term stability of lining structure.In this paper,Muzhailing railway tunnel is referenced and Burgers rheological model is used to analyze the changing law of the supporting structure stress over time in different rheological periods.The results show that:(1) Burgers model can better demonstrate surrounding rock rheological properties;(2) the current supporting structure of Muzhailing Tunnel is subject to greater risk of crushing and cracking in a few years time;(3) the reduction of rheological properties and improvement of surrounding rock strength should depend on the change of surrounding rack rheological properties.