Numerical simulation and safety analysis for tunnel excavation near gob with groundwater

摘要

The huge groundwater usually surges from a watereroded cave or gob during the deep mining and construction of deep-buried long tunnel. It is very important to study the simulation and control of damage resulted from the underground cavern (e.g. gob) with groundwater for the tunnel excavation. Based on the rules of groundwater movement, the hydraulics theory and the seepage principles of fractured rock masses, associated with the geological conditions of the Changba Lead-zinc Mine, the damages resulted from the gob with groundwater for the tunnel excavation were simulated and analyzed using FLAC3D software. The changes of the stress, strain and displacement of the rock masses around the gob and tunnel was obtained under the condition of gob with groundwater. The changes of the plastic zone and stress field were analyzed, the minimal thickness of waterproof layer for keeping tunnel safe was estimated. Based on numerical modelling, a series of curves for rock mass response and deformation are obtained, which provides the basis of guiding the design and construction of rock tunnels in underground mines.