Abstract:

Waves generated by the instability of perilous rockmass were numerically simulated. The Jianchuandong perilous rockmass at Wushan county in the Three Gorges Reservoir area was taken as the research object. In the simulation, the reservoir water level was set as 175m, the perilous rock completely sit-slid into the water, and the simulated length of bank slope was 6 km. Diagrams of instantaneous water surface, wave height in the waterway, and maximum climb-height of wave and pre-warning were obtained. Results revealed that under the simulation condition, the maximum wave height was 32.1m, and the maximum climb-height of wave at the opposite bank was 24.1m. Furthermore, the wave propagation along the channel was divided into sharp attenuation and gentle attenuation. The sharp attenuation lasted for 800m, 400m in the upstream and another 400m in the downstream, which is the most perilous navigation area affected by the wave. In this area, the wave height declined in an exponential function, averaging 4m per 100m length. Whereas in the gentle attenuation area, the wave height declined in a slow gradual curve, averaging 0.1- 0.2m per 100m. According to this regularity, the height of waves which propagates to Wushan county was 1-2m, 1.5-2.5m at the bank slope of Baolong river, and 1.0-1.5m at Peishi township. The method in this research could serve as a reference for the prediction and risk assessment of wave disaster.

Key words: Three Gorges Reservoir area, perilous rock, impulse wave, numerical simulation