富水隧道深埋排水沟衬砌水压力特征数值分析

Numerical Analysis on Water Pressure Characteristics of the Lining in Water-rich Tunnel with Deep-buried Drainage

采用二维流固耦合数值分析方法,研究仰拱下设置深埋排水沟的排水方式下衬砌水压力分布特征:仰拱结构下积水通过深埋中心管沟排出,仰拱衬砌水压力最小,拱顶衬砌水压力最大,拱腰和边墙衬砌水压力居中.对不同工况进行对比分析,研究衬砌水压力的影响因素.结果表明:增大排放量,能减小衬砌水压力,但排放量过大造成地下水流失,限排标准应综合分析确定;注浆能减小衬砌水压力,注浆圈厚度以5~6 m为优,继续增大注浆圈厚度,衬砌水压力减小不明显;减小注浆圈渗透系数,衬砌水压力减小,通过注浆将围岩渗透系数降低到注浆前的1/50左右是比较合理的,渗透系数继续减小,衬砌水压力减小不明显.

Using the two-dimensional fluid-structure coupling numerical analysis method,the water pressure characteristics of lining in the tunnel with deep-buried drainage ditch are studied.Water under the inverted arch structure is discharged through deep-buried central pipe trench.The water pressure of inverted arch lining is the smallest,the water pressure of vault lining is the largest,and the water pressure of arch waist and side wall lining is in the middle.The influencing factors of lining water pressure are studied through comparative analysis of different working conditions.The results show that increasing the discharge amount can reduce the pressure of lining water,but excessive discharge leads to groundwater loss.The discharge limit standard should be determined by comprehensive analysis.Grouting can reduce the water pressure of lining.The reasonable thickness of grouting ring is 5~6 m.The thickness of grouting ring will continue to increase,but the decrease of water pressure of lining is not obvious.With the decrease of the permeability coefficient of grouting ring,the water pressure of lining decreases.Through grouting,it is reasonable to reduce the permeability coefficient of surrounding rock to about 1/50 before grouting.The permeability coefficient continues to decrease,and the water pressure of lining decreases insignificantly.