水位与进尺及支护时机对富水隧道稳定性的影响

Influence of different water levels, footages and supporting time on the stability of rich water tunnel

以实际富水隧道为参考背景,通过不同水位、支护、开挖条件建立三维数值模拟,分析富水隧道在不同条件下的稳定性及围岩变形。研究结果表明:地表沉降和开挖面的水平位移均随着水位的上升而增加,并且水位越接近地表,地表沉降和开挖面的水平位移增加得越明显;支护在滞后2.5 m时,相应的拱顶沉降和塑性区与及时支护条件下相差不大,但在支护滞后5.0 m时,拱顶沉降和塑性区域显著增大,并且塑性区向上部围岩蔓延;随着进尺增加,围岩位移与塑性应变增大;随着渗流时间增加,掌子面前方的孔隙水压力逐渐减少,逐渐呈现漏斗状分布。

Based on the actual rich water tunnel,three-dimensional numerical simulation was carried out to analyze the stability and deformation of surrounding rock under different conditions by different water levels,support and excavation conditions.The results show that the surface subsidence and the horizontal displacement of the excavation surface increase with the increase of the water level,and the closer the water level is to the surface,the more obvious the surface subsidence and the horizontal displacement of the excavation surface increase,and the vault settlement and plastic zone have little difference between the case of 2.5 m behind the support and the timely support condition,but in the case of 5.0 m behind the support,the vault settlement and plastic zone increase obviously,and the plastic zone spreads to the upper part of the surrounding rock.The surface subsidence and the plastic zone of excavation surface increase with the increase of the excavation footage.With the increase of seepage time,the pore water pressure in front of tunnel face becomes smaller and smaller,and gradually presents funnel-shaped water pressure distribution.