广西某高速公路基于切线角理论的隧道变形监测预警应用研究

Application Research of Tunnel Deformation Monitoring and Early Warning Based on Tangential Angle Theory in an Expressway in Guangxi

经典边坡变形曲线“三段式”由日本学者斋藤提出,即位移-时间曲线上的三个典型阶段:初始变化阶段、等速变化阶段及加速变化阶段。前人根据三个不同变形阶段的位移-时间曲线斜率变化关系提出了切线角的概念,基于此建立了边坡监测预警判断系统。施工期隧道围岩变形监测位移-时间变化曲线同样满足“三段式”,引入位移切线角概念进行隧道围岩变形监测预警,保证位移与时间曲线的坐标度量单位不同,在计算时容易造成定义上的不严谨,数值分析结果不确定的特点,通过对位移时间曲线做变化,实现横纵坐标轴量纲一致,通过离散小波分析方法分析位移三阶段,计算位移速率,进而求取切线角。构建隧道围岩变形曲线“三段式”预警定量分级标准,给出隧道围岩变形预警判断依据。对已有的隧道围岩变形实例研究结果表明,引入切线角进行隧道围岩变形监测预警中具有较大的应用价值。

The classic slope deformation curve"three-stage"was proposed by Saito,a Japanese scholar,three typical stages on the displacement-time curve,including initial change stage,constant velocity change stage and accelerated change stage.The concept of tangential angle was put forward by predecessors according to the relation of slope change of displacement-time curve in three different deformation stages,based on which the slope monitoring and early warning system was established.Displacement-time curve of tunnel surrounding rock deformation monitoring during construction period also meets the"three-stage type".The concept of tangent angle of displacement is introduced to monitor and warn tunnel surrounding rock deformation.In order to ensure that the coordinate measurement units of displacement and time curve are different,the definition is easy to be imprecise in calculation and the results of numerical analysis are uncertain.To achieve the horizontal and vertical axes dimensional consistency,through discrete wavelet analysis method to analyze the displacement of three stages,calculate the displacement rate,and then get the tangent angle.The quantitative classification standard of"three-stage"early warning of tunnel surrounding rock deformation curve is constructed,and the judgment basis of tunnel surrounding rock deformation early warning is obtained.The results of the existing case study of tunnel surrounding rock deformation show that the introduction of tangent angle has great application value in monitoring and warning of tunnel surrounding rock deformation.