富水地区隧道注浆圈内部水压分布规律

Inner water pressure distribution law of the tunnel grouting circle in water-rich area

为确定富水地区限排隧道中适宜的注浆参数,采用室内模型试验和数值模拟手段,研究注浆圈内部水压分布规律及注浆圈外、注浆圈内、二衬外水压联动特征,并分析注浆圈厚度、注浆圈渗透系数、隧道埋深等关键因素对注浆圈内部水压的影响.结果表明:不同注浆厚度时,在隧道相同部位水压力量值十分接近,扩大注浆范围对降低水压力的作用并不明显;渗流模型试验与数值分析结果基本一致,深埋和浅埋隧道围岩的测点水压力均呈现从注浆圈外部至二衬背后逐渐减小的趋势,但浅埋地层中量值变化幅度更大,渗流影响范围更广;渗流场各测点水压力与地下水位高度关联性较大,而与隧道埋深关联性并不大;深埋和浅埋隧道注浆圈内部拱顶和拱腰位置的水压力均表现出衰减逐渐增大的非线性特征,且随着注浆圈渗透系数降低更加明显,而拱底处水压接近线性变化;注浆圈渗透系数减小时,二衬外水压力同步减小,注浆圈外侧水压力逐渐增加,但变化幅度总体较小,依靠不断降低注浆圈渗透系数来控制围岩-支护体系的水压力并不经济.

To determine the appropriate parameters of grouting in the limited discharge tunnel in water-rich area,the inner water pressure distribution law of the tunnel grouting circle and the hydraulic linkage characteristics of the inside and outside of the grouting circle and the back of the secondary lining were studied by the indoor model test and numerical simulation.The influence of key factors such as the thickness of grouting circle,the permeability coefficient of grouting circle and tunnel depth on the inner water pressure of grouting circle was analyzed.The results show that when the grouting thickness varies,the water pressure is very close at the same part of the tunnel.And the effect of expanding the scope of grouting to reduce the water pressure is not obvious.The model test and numerical analysis have similar results.Thewater pressure of most measurement points gradually decreases from the outside of the grouting circle to the back of the secondary lining in both deep and shallow buried tunnel.But in shallow buried strata,the variation range of water pressure is bigger,and the influence of seepage is wider.Instead of the depth of tunnel,the water pressure of measurement points in the seepage field is interrelated significantly with the height of groundwater level in the seepage field.Water pressure of arch crown and arch waist position of both deep buried and shallow buried tunnel presents the nonlinear characteristics of the gradually increased of attenuation.This trend is more obvious with the decrease of the permeability coefficient of grouting circles.The variation of water pressure is approximately linear at the bottom of arch.The external water pressure of secondary lining decreases synchronously with the decrease of grouting circle permeability coefficient.And water pressure of the outside of the grouting circle is increasing.But the amplitude of the change is small.It is not economical to control the water pressure of the surrounding rock-supporting system by reducing the permeability coefficient of the grouting circle continuously.