The failure characteristics around shallow buried tunnels under rainfall conditions

The instability of weak surrounding rock around shallow buried tunnels induced by rainfall is a challenge for tunnel engineering and threatens construction safety. To reveal the influence on tunnel, results experiments failure under different intensities durations using self-developed test system are presented. First, stress seepage behaviors were analysed, showed that increased while pore water pressure decreased as intensity decreased. It was more difficult to maintain vault collapse increased, particle erosion in model intensified duration increased. change greater than stress, but pressures influenced each other during rainfall. at top two sides because channels developed collapsed easily due smaller stresses. According phenomena observed test, evolution progressive roughly divided into eight stages: stability, drop, continuous flow, partial collapse, mud mixture, throughgoing massive gushing. Furthermore, final pattern consists an excavation disturbance zone, damage zone zone. This research helps conditions can be used reference designing disaster prevention strategies practical engineering.