高地应力缓倾软硬互层岩体中隧道底鼓影响因素模拟分析

当隧道穿越以水平构造应力为主导的高地应力区,特别是隧底下伏缓倾软硬互层岩体时,易发生隧道底鼓变形。选用侧压力系数、岩层倾角、围岩厚度、围岩弹性模量、隧道埋深5种影响因素,通过FLAC 3D建立数值计算模型,研究单一影响因素和多因素耦合对隧道底鼓的影响规律。结果表明:在单一影响因素下,隧道底鼓量随侧压力系数和围岩厚度的增大先增大后减小,随围岩倾角和围岩弹性模量增加而减小,随隧道埋深增加而增大;在多因素耦合作用下,各因素对隧道底鼓的影响显著性排序依次为隧道埋深>侧压力系数>硬质岩弹性模量>岩层倾角>硬质岩岩层厚度。

Simulation Analysis of Influencing Factors of Tunnel Gloor Heave in the Gently Inclined Soft Hard Interbedded Rock Under High Geostress

When the tunnel passes through the high geostress area dominated by horizontal tectonic stress,especially when there is a gently inclined soft hard interbedded rock under the tunnel,the deformation of tunnel floor heave is easy to occur.Five influencing factors were selected,including lateral pressure coefficient,strata inclination,thickness of surrounding rock,elastic modulus of surrounding rock and tunnel buried depth,and the numerical calculation model was established by FLAC 3D to study the influence law of single influencing factor and multi factor coupling on tunnel floor heave.The results show that under a single influence factor,the volume of tunnel floor heave increases first and then decreases with the increase of lateral pressure coefficient and thickness of surrounding rock,decreases with the increase of inclination and elastic modulus of surrounding rock,and increases with the increase of tunnel buried depth.Under the coupling effect of many factors,the significant order of the influence of each factor on tunnel floor heave could be tunnel buried depth>lateral pressure coefficient>elastic modulus of hard rock>strata inclination>thickness of hard rock.