ADVANCE ON THE METHODS FOR PREDICTING WATER INFLOW INTO TUNNELS

Groundwater inflow is one of the widespread disasters in underground tunneling, which directly affects the construction progress, the stability of the cave and resident safety. A large number of studies in predicting the groundwater inflow have proposed various methods associated with different application conditions. However, in order to accurately predict the groundwater inflow into tunnels, it is crucial to select a reasonable method for the specific condition. In this study, the previous methods are classified into four different types including empirical formula, analytical formula, numerical and physical simulation methods. The empirical formula method originates from the compilation of numerous engineering cases, focusing on similar geological conditions. The analytical formula method based on the strict theoretical derivations provides a fast and simple way for the assessment of groundwater inflow into tunnels. The numerical simulation method can analyze the complicated hydrogeological conditions. The physical simulation method intuitively characterizes the inflow laws by experiments. The theoretical principles, merits and drawbacks of these methods are summarized in detail. Furthermore, some potential research topics are prospected for further improvement.