水岩分算隧道衬砌外水压力折减系数取值方法

针对如何确定水岩分算时隧道衬砌外水压力折减系数问题，结合已有隧道规范中地下水处理的规定及外水压力折减系数经验取值方法，从地下水渗流作用出发，基于地下水水力理论，推导了地下隧道渗水量和复合衬砌结构外水压力折减系数理论求解公式，揭示了灌浆圈、初期支护、二次衬砌渗透系数及灌浆圈厚度等参数的变化对隧道渗水量和衬砌外水压力折减系数的影响规律。在此基础上提出了不同衬砌类型外水压力折减系数取值所应注意的问题及相应的取值方法。研究结果可为隧道工程的防排水系统设计提供借鉴和参考。

Method to determine reduction factor of water pressure acting on tunnel linings using water-rock independent calculation methodology

In order to accurately determine the reduction factor of water pressure acting on tunnel linings, a method to determine the water load acting on the composite linings and the water discharge in the tunnel is derived based on the correlation theory of groundwater hydraulics from the groundwater seepage action by means of the groundwater treatment regulations in the tunnel codes and the empirical methods. The influences of variable parameters of primary support, secondary support and grouting circle on water inflow and reduction factor of external water pressure are released by using the theoretical analysis. The problems which should be paid attention to and the methods to determine the value of reduction factor of water pressure acting on different kinds of tunnel linings are studied. The results may provide references for the design of tunnel waterproofing and drainage system in high water pressure regions.