不考虑开挖扰动影响的隧道涌水量预测模型试验研究

Experimental study on tunnel inflow without considering the influence of excavation disturbance

采用大型施工及运营期矿山法隧道渗流模型试验系统,在不同的注浆圈和初衬渗透系数下,不考虑隧道开挖的扰动影响进行涌水量预测,并以Visual-modflow软件进行数值建模分析,结果表明:两者涌水量结果和规律基本吻合,随注浆圈或初衬的渗透系数减小,其试验平均涌水量值均呈非线性下降,各工况单次试验测试值的离散性也逐渐减小,而降低注浆圈渗透系数对涌水量的影响更为明显;改变注浆圈渗透系数,各工况连续采集涌水量结果呈先减小后增大至逐渐平衡的趋势,而改变初衬渗透系数则呈现涌水量逐渐减小直至平衡的趋势;非扰动开挖使地下水向隧道内汇集,隧道周围水力坡度明显增大,等水位线分布密集,掌子面附近等水位线沿隧道开挖方向凹陷;完善的防水体系(初衬及注浆圈)对保持地下水稳定起到显著作用,可有效减弱局部水力联系,减小渗流影响范围,地下水降幅也明显减小。研究方法及成果对类似工程设计和施工具有一定的指导作用。

A seepage model test system for mining tunnel during construction and operation period has been used to predict the water inflow of a tunnel without considering the influence of excavation disturbance. The test conditions include the different permeability coefficient of grouting circle and initial lining. The numerical analysis was carried out with the Visual-modflow. The results from experiment and numerical analysis are basically consistent. The average value of water inflow is nonlinearly decreased with the decreasing of the permeability coefficient of the grouting circle and the initial lining, and the variance of single test value in each condition is also gradually reduced. The effect of reducing the permeability coefficient of grouting circle on the water inflow is more obvious. When the permeability coefficient of grouting circle was changed, the continuous collection of water inflow in each condition decreased first and then increased gradually to a stable value. And when the permeability coefficient of the initial lining was changed, the water inflow showed the trend of the gradually decreasing until it reached a balance. Non-disturbed excavation makes the groundwater to flow towards the tunnel which leads to the notable increase of hydraulic gradient around tunnel. The distribution of isopiestic line is dense and presents a concave shape in the direction of tunnel excavation. The well-functioning of the waterproof system（primary lining and grouting circle） played a significant role in maintaining the stability of groundwater. It effectively reduced the local hydraulic connection, reduced the influence of the seepage. The lowering of groundwater table was also significantly reduced.