Abstract: To examine the influence of the cross-sectional shape, cavern spacing, and buried depth of the underground water-sealed cavern on the stability of the surrounding rock of the cavern, feasible rock stability discrimination indicators are established based on the mechanical meaning of the Mohr-Coulomb failure criterion. Then, finite element simulation software is used to study the rock stability under various working conditions, with rock safety factor, deformation, and stress as primary discrimination indicators. The research results reveal the following: (1) In the simulated single cavern working condition, the horizontal displacement of the straight wall shaped cavity is slightly smaller than that of the curved wall circular arch shaped cavity, and the straight wall shaped cavity is slightly larger than that of the curved wall shaped cavity. The stress distribution of the curved wall shaped cavity is relatively uniform, which is more conducive to the stability of the surrounding rock. (2) The stability of the surrounding rock in the main cavern of the underground water sealed cavern varies, with the stability of the surrounding rock at the bottom of the cavern being better, followed by that at the top, and that on both sides of the cavern being poorer. (3) The increase in the spacing between adjacent caverns leads to an increase in the stability of the surrounding rock, but the improvement effect is no longer significant when the spacing of the tunnel is doubled tunnel span. (4) In the underground cavern group, the vertical displacement of the central cavern is significantly higher than that of the edge cavern; and the horizontal displacement of the left and right sidewalls in the edge cavern differ significantly. (5) As the burial depth of the cavern increases, the stability of the surrounding rock around the cavern decreases. When the burial depth of the cavern is over 150 m, reinforcement measures for the surrounding rock should be implemented to ensure the stability of the cavern.

Key words: water-sealed cavern, surrounding rock stability, safety factor, cavern spacing, numerical simulation