动力扰动下巷道围岩变形影响因素敏感性分析

Sensitivity analysis of roadway surrounding rock deformation factors under dynamic disturbance

基于高地应力状态下煤矿井下巷道在开采工程中由于覆岩层断裂、岩巷爆破掘进等动力扰动导致围岩更容易变形甚至失稳的情况,根据弹性理论和应力波理论,分析了扰动状态下巷道围岩失稳机理,采用FLAC3D软件建立了巷道围岩的理想弹塑性模型,在正交优化组合的基础上对动力扰动下影响巷道围岩变形的因素(应力峰值、频率、侧压力系数和扰动时间)进行敏感性分析。结果表明:不同影响因素对巷道顶板和帮部最大位移的敏感性有较大的差异性;分析16种参数值不同组合条件下的变形量,得出应力峰值20 MPa,频率1 Hz,侧压力系数1.4,扰动时间0.8 s时,顶板及两帮变形程度最大;应力峰值5 MPa,频率15 Hz,侧压力系数0.8,扰动时间0.2 s时,顶板及两帮变形程度最小;顶板和帮部位移影响因素的敏感性由大到小依次为:侧压力系数、扰动时间、应力峰值和频率。最后,利用多元线性回归分析法建立了多因素作用下顶板和帮部变形的数学公式,回归效果显著,为巷道的有效支护提供了工程参考。

The surrounding rock of the underground tunnel is more likely to to be deformed or even unstabledue to dynamic disturbances such as fracture of overburden,blasting and excavation of rock roadway in coal mining under high ground stress.Based on the elastic theory and stress wave theory,the mechanism of tunnel surrounding rock instability under disturbance is analyzed. The ideal elastic-plastic model of roadway surrounding rock is established by FLAC3 Dsoftware. On the basis of orthogonal optimization combination,the sensitivity analysis of factors( peakstress,frequency,lateral pressure coefficient and disturbance time) affecting roadway surrounding rock deformation under dynamic disturbance is carried out.The results show that different influencing factors have great differences in the sensitivity of the maximum displacement of roof and ribs of the tunnel;By analyzing the deformation under 16 different combinations,it is found that the deformation degree of roof and sides is the greatest when peakstress is 20 MPa,frequency is 1 Hz,lateral pressure coefficient is 1.4,disturbance time is 0.8 s,the deformation degree of roof and sides is the lowest whenpeakstress is 5 MPa,frequency is 15 Hz,lateral pressure coefficient is 0.8,disturbance time is 0.2 s. The sensitivities that affect the deformation of roof and sidesare in the order of lateral pressure coefficient,disturbance time,peakstress and frequency. Finally,a multiple linear regression analysis method was used to establish the mathematical formulas of roof and slab deformation under the action of multiple factors. The regression effect is very remarkable,which provides engineering reference for the effective support of roadways.