非达西渗流效应对深埋圆形隧洞弹塑性解的影响

Influence of Non-Darcy Seepage Effect on Elastoplastic Solution of a Deep-buried Circular Opening

基于Izbash非Darcy渗流模型,求解深埋圆形隧洞围岩的非线性渗流场解析解;将渗透水压力视为体积力作用于应力场,推导隧洞围岩弹性解析解和基于Mohr-Coulomb屈服准则的塑性解析解。结合算例,对Izbash非线性渗流模型与Darcy模型中隧洞围岩水力坡度与应力分布曲线、隧洞内外水压差与塑性区半径的关系曲线、围岩特征曲线进行对比与验证。研究表明:隧洞内外水头高差相同条件下,与Darcy渗流模型相比,Izbash非线性渗流模型中水力坡度曲线较平缓,但两模型水力梯度曲线会相交;隧洞围岩径向和切向压力均偏大,围岩塑性区半径偏小;位于高水压地区的深埋隧洞,应考虑非线性渗流对隧洞弹塑性解的影响。

Based on Izbash＇s non Darcy seepage model, the analytical solution for nonlinear seepage field of deep buried circular openings was derived. Taking into account of seepage force, which was regarded as the volume force acting on the stress field, the elastic solution of circular openings was derived. Furthermore, the plastic solution of circular openings was concluded by using Molar Coulomb fallure criterion. Numerical exam ples were used to compare and verify the distribution curve of hydraulic gradient and stress of the tunnel sur rounding rock, the relation curve between hydraulic head pressure and radius of plastic zone inside and outside the tunnel,and the characteristic curve of the surrounding rock under Izbash＇s seepage model and Darcy＇s see page model. The results show that under the same hydraulic head pressure difference and compared with Dar cy＇s seepage model, the curve of hydraulic gradient under Izbash＇s seepage model is flat, but the two curves of the two models will intersect each other. Both the axial and radial stress of the surrounding rock is larger and the radius of plastic zone is smaller. The influence of non Darcy seepage effect on elastoplastic solutions of a deep buried circular opening located in high hydraulic pressure area should be considered.