水工压力隧洞挪威准则的修订

Revision of the Norway Criterion for Hydraulic Pressure Tunnel

水工压力隧洞的设计需要满足三大准则,其中挪威准则通常是输水线路立面布置的主要制约因素之一。挪威准则只考虑了地形、岩体风化深度的影响,没有考虑岩体强度、结构面发育程度的影响。理论分析及工程实践发现,压力隧洞上覆岩体抬动破坏过程中与下部岩体发生了相对运动,产生了作用力,考虑在重力分量作用下岩柱与下部岩体的摩擦作用是必要的。此外,还应验算垂直~水平方向范围内各角度下的岩体厚度是否满足要求。通过增加考虑摩擦系数μ和计算方向θ两个主要参数,建立了最小埋深计算公式,该公式在一定条件下可简化为挪威准则公式。经过计算对比,修订的挪威准则公式在岩体结构面性状较好时,计算最小埋深显著小于挪威准则,从而为缩短压力隧洞钢衬长度、节约投资提供了条件。

The design of pressure tunnel should meet three criteria,among which the Norway criterion often is one of the main factors for the layout of water diversion tunnel.The Norway criterion only considers the influence of terrain and weathering depth of rock mass,but does not consider the influence of rock mass strength and structural planes development.The theoretical analysis and engineering practice show that the rock mass moves relative to the underlying rock mass in the lifting process,so it is necessary to consider the friction force between rock pillar and underlying rock mass caused by the gravity component,and in addition,it is also necessary to check whether the thickness of rock pillar at various angles meets the requirements.By adding friction coefficientμand direction angleθ,a formula for calculating minimum buried depth is established in this paper,and this formula can be simplified to the Norway criterion formula under certain condition.Through calculation and comparison,the calculated minimum buried depth of the formula is significantly smaller than the Norway criterion when the structural planes of the rock mass have a well condition,which provides supports for shortening the steel lining length of pressure tunnel and saving investment.