为探究地下水封洞库洞室断面形状、洞室间距及埋深对洞库围岩稳定性的影响，根据摩尔-库仑破坏准则的力学含义，建立可行的围岩稳定性判别指标，运用有限元模拟软件，以围岩安全系数、变形、应力为主要判别指标对各工况下围岩稳定性进行研究。研究结果表明： 1）在所模拟的单洞工况中，直墙形洞室竖向位移略小于曲墙圆拱形洞室，而水平位移要略大于曲墙形，曲墙形洞室应力分布相对均匀，更有利于围岩稳定。2）地下水封洞库主洞室各部位围岩稳定性不同，其中，洞室底部围岩稳定性较好，其次为顶部围岩，洞室两侧围岩稳定性较差。3）相邻洞室间距增加，围岩稳定性增加，但间距增加至2倍洞跨后，围岩稳定性改善效果不再明显。4）在地下洞室群中，中部洞室竖向位移明显高于边部洞室，边部洞室左右侧壁水平位移值相差较大。5）洞室埋深增加，洞周围岩稳定性会降低，尤其是在洞室埋深为150 m时需采取围岩加固措施，以保证洞室的稳定性。
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.
