基于水-力耦合理论的超深隧道围岩渗透性预测

摘要

To predict water-gushing is one of the principal problems faced in the surveying and designing extra-long tunnels. To obtain hydraulic conductivity（HC） is the basis to forecast water-gushing and HC can not be determined by pumping test on a large scale for tunnels with superthick overburden. According to the hydraulic-mechanical coupling theory, the paper puts forward a method to predict the wall rock permeability for tunnels with superthick overburden. Its main steps are as follows: (1) to determine the tensor of hydraulic conductivity of the rock mass near the ground; (2) to back-analyzing of stress field; (3) to predict the fissure aperture at different levels; (4) to suppose the structure of fissure network not to vary with depth and to calculate the tensor of hydraulic conductivity of the wall rock.%涌水预测是特长超深隧道勘测设计及施工中面临的重要问题之一。围岩渗透性是涌水预测的基础，对于超深隧道，不能通过大规模抽水试验来获得渗透性参数。以水力耦合理论为基础，该文提出了一种超深隧道围岩渗透性预测方法。其主要思想是，首先确定近地表岩体的渗透张量；根据地应力实测资料进行地应力场的量级反演；选择适当的裂隙开度-应力模型，预测不同深度的裂隙开度；在裂隙网络结构不随深度变化这一假定的基础上，计算隧道标高的围岩渗透性。