基于变形潜势的挤压性围岩隧道控制技术研究

Research on the Control Technology of Squeezed Surrounding Rock Tunnel Based on Deformation Potential

研究目的:随着铁路、公路交通网络建设的推进,挤压性隧道大变形现象十分突出,常常伴随着大规模的变形破坏,变形控制难度极大。挤压性围岩隧道变形控制的主要难点是如何划分变形潜势等级、确定支护体系和施作时机。本文结合以往挤压性大变形隧道建设经验,对挤压性围岩隧道上述基本问题进行深入的分析探讨,达到控制变形的目的。研究结论:(1)基于应力场分布特点,将挤压性围岩隧道变形分为“应力型”、“构造型”、“复合型”三种类型;(2)变形潜势是指围岩内部潜在应变能的强弱,可根据变形总量将变形潜势分为“常规、轻微、中等、强烈”;(3)变形潜势随变形速率的增大而增强,可根据支护初期变形速率评价变形潜势强弱、围岩与支护体系适应性;(4)揭示了挤压性围岩隧道长、中、短锚杆的作用机理,提出了锚固体系施作时机,确定了合理的钢架的形式、预留变形量;(5)提出挤压性围岩二次衬砌施作时机可按2~4 mm/d控制;(6)本研究能够为挤压性围岩隧道的设计及变形治理提供参考。

Research purposes:With the advancement of railway and highway transportation network construction,the large deformation phenomenon of the squeezed tunnels is very prominent,often accompanied by large-scale deformation and damage,and the deformation control is extremely difficult.The main difficulty in the deformation control of squeezed surrounding rock tunnels is how to divide the deformation potential level,determine the support system and the timing of the implementation.Based on the previous experience of construction of squeezed large deformation tunnels,this paper analyzes and discusses the above basic problems of squeezed surrounding rock tunnels to achieve the purpose of controlling deformation.Research conclusions:(1)Based on the distribution characteristics of the stress field,the deformation of the surrounding rock tunnel is divided into three types:"stress type","structural type"and"composite type".(2)Deformation potential refers to the strength of potential strain energy inside the surrounding rock.The deformation potential can be divided into"conventional,slight,medium and strong"according to the total deformation.(3)The deformation potential increases with the increase of the deformation rate,and the deformation potential and the adaptability of the surrounding rock and the support system can be evaluated according to the initial deformation rate of the support.(4)The mechanism of the long,medium and short anchors of the squeezed surrounding rock tunnel is revealed,the timing of the anchor system is proposed,and the reasonable form and reserved deformation of the steel frame are determined.(5)It is proposed that the timing of the secondary lining of the squeezed surrounding rock can be controlled by 2~4 mm/d.(6)The research result can provide reference for the design and deformation control of squeezed surrounding rock tunnels.