基于水-力耦合理论的超深隧道围岩渗透性预测

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。

PREDICTION OF WALL ROCK PERMEABILITY FOR TUNNELS WITH SUPERTHICK OVERBURDEN

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.