隧洞围岩前期监测位移损失计算及力学参数敏感性分析

Calculation of displacement loss and sensitivity analysis of mechanicalparameters in early monitoring of surrounding rock in tunnels

隧道围岩变形监测仪器埋设具有滞后性,导致仪器安装前的位移无法获取,给监测与仿真计算的对比分析造成了困难。基于围岩物理力学参数的单一变量计算数据,对弹性模量、黏聚力和内摩擦角进行敏感度分析,拟合给出LDP(Longitudinal displacement profile)曲线及全过程损失位移占比,进一步给出Hoek经验公式的参数K_(1),K_(2),对原位监测曲线进行拟合,寻找并确定与原位监测曲线匹配度最优的计算位移曲线,计算出监测位移最大损失值,并修正监测全位移曲线,修正后的曲线与样本曲线误差较小,为监测位移损失确定和隧道安全稳定提供了一种新的研究方法。

The installation of instrument for the deformation monitoring of surrounding rock in tunnels often delays and the displacement before the installation of instrument cannot be obtained,which makes monitoring and simulation calculations difficult.In this paper,a sensitivity analysis of elastic modulus,cohesion and internal friction angle is conducted based on the single variable calculation data of physical and mechanical parameters of surrounding rock.The LDP(Longitudinal displacement profile)curve and the displacement loss fraction in the whole process are fitted and the parameters K_(1) and K_(2) in Hoek s empirical formula are further obtained.The in-situ monitoring curve is fitted to determine the calculation displacement curve that best matches it.The maximum loss value of the monitoring displacement is calculated and the whole monitoring displacement curve is corrected.The error between the corrected curve and the sample curve is small.This provides a new research method for determining the monitoring displacement loss and for the safety and stability of tunnels.