软弱围岩隧道施工过程荷载释放特性

Stress release characteristics during the construction process of soft rock tunnel

针对软弱围岩隧道施工过程中荷载释放过程的复杂性和多样性这一问题,以明垭子隧道为例,采用现场试验和数值模拟等手段,对明垭子隧道施工过程中的围岩荷载释放特性进行分析。结果表明:上台阶施工对围岩压力释放的影响较小;中台阶开挖会引起围岩压力释放速率急剧增大;下台阶开挖时围岩压力释放速率有一定程度的加快。仰拱闭合后减缓了围岩压力的释放速率,可用周边位移作为围岩压力释放的判断依据。分析得到了软弱围岩隧道施工过程中荷载释放特性和工序、位移的关系,旨在为软弱围岩隧道的设计和施工提供参考。

Mingyazi tunnel was used to study the complexity and variety of stress release process during the construction process of soft rock tunnel.Field test and numerical simulation methods were employed to analyze the stress release characteristics during the construction process of Mingyazi tunnel.It was known that the upper step construction has less influence on the pressure release of surrounding rock.The pressure release rate of the surrounding rock increased sharply with the excavation of the middle steps.The pressure release rate of surrounding rock was accelerated to a certain extent when the lower steps were dug.The pressure release rate of the surrounding rock was slowed by the closing of the inverted arch.The peripheral displacement can be used as the basis for the determination of surrounding rock pressure release.The relationship between the load release characteristics during the construction process and construction sequence as well as displacement were obtained.This can be used as a reference for the design and construction of soft rock tunnel.