用于均质地层隧道渗流场的两种轴对称解

在均质地层中,分别以推广轴对称解与周长等效公式两种方法,研究非圆形断面隧道衬砌水压力,并结合水压力折减系数提出修正施工水荷载的方法。以墙脚处为分析点,将适用于圆形断面的轴对称解推广至非圆形断面,同时提出等效轴对称解,分析两者在不同衬砌与注浆圈渗透系数、衬砌与注浆圈厚度的分析点水压力与渗流量,对比两者与数值解的误差。研究表明:两种理论解得到的衬砌水压力值较为接近,但渗流量差异较大;数值解与等效轴对称解的误差小于与推广轴对称解的误差,数值解大于两种理论解,三种计算结果趋势一致;通过工况与水压力折减系数和渗流量的拟合曲线及水压力折减系数公式,插值计算水压力并实时调整水荷载。推荐在非圆形隧道断面水荷载设计时优先采用等效轴对称解析解的方法。

Study on Two Kinds of Axisymmetric Solution for Seepage Filed of Tunnel in Homogeneous Formation

To study lining water pressure of noncircular section tunnel,two methods that extended axisymmetric solution and formula of perimeter equivalence are used respectively in homogeneous reservoir.Combined with reduction factor of water pressure,the measure of modifying water load during construction is put forward.Foot of wall is taken as analysis point,axisymmetric solution adjusted to circular section is extended to noncircular section,and the equivalent axisymmetric solution is proposed.In different lining and grouting circle permeability coefficient,lining and grouting circle thickness,water pressure and seepage discharge of two solutions are analyzed.The error between two solutions and numerical solution are compared.Research shows that,two solutions obtain basically the same lining water pressure caused by seepage,but there is great difference in the seepage discharge.The error between numerical solution and equivalent and axisymmetric solution is less than the error between numerical solution and axisymmetric solution.The numerical solution is more than the axisymmetric solution,and trend of result in three solutions is consistent.By fitting curve in reduction factor of water pressure and seepage discharge and factor of water pressure formula,water pressure is calculated in interpolating and water load is adapted in time.The equivalent and axisymmetric solution used in noncircular section should be priority to designing water load.