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Liu C.-Z.,China Institute for Geo Environment Monitoring | Miao T.-B.,Gansu Bureau of Surveying and Mapping | Chen H.-Q.,China Institute for Geo Environment Monitoring | Dong K.-J.,Gansu Institute for Geo Environment Monitoring | And 2 more authors.
Geological Bulletin of China | Year: 2011

The Zhouqu event happened at 0:12 of Aug. 8, 2010 in Zhouqu County of Gansu Province of China. It is an oversize mountain torrent-debris flow disaster which brought about momentous casualty and loss of belongings. It is finished with Aug. 30. There are 1467 death and 298 lost having been discovered in this disaster. It is calculated for that total volume of the solid deposits are 181×104m3 which rush out from Sanyanyu and Luojiayu gullies through grid calculation. The movement time from two mountains to Zhouqu County is separately 2.1 minutes for Sanyanyu and 4.3 minutes for Luojiayu on velocity calculation of the mountain torrent head in different sections in this disaster. The distances from two mountains to Zhouqu County are all about 2km in Sanyanyu and Luojiayu. The causes of formation about Zhouqu tragedy involved Sanyanyu being a debris flow gully of high frequency in history, the northern mountainous area producing strong potential energy impulsion, a rich of loosing rock or soil body in the gullies, rockmass loosing and cracking derived from many times of historical earthquakes, a long period of drought in this region since 2010 made in rock/soil body crack opening, the maximum rainfall to cause this calamity in the area at Aug. 7, the mountain torrent-debris being of concealment in gestation, abruptness in happening and truculency in destruction, etc. Moreover, some buildings occupy and use partly the routeway in which a torrent-debris flows into Bailongjiang River in Zhouqu County in rapid urbanization.

Huang B.,Wuhan University | Yin Y.,China Institute for Geo Environment Monitoring
Landslides | Year: 2012

At 4:40p. m. on November 23, 2008, the Gongjiafang slope collapsed on the north bank of Yangtze River in Wu Gorge of Three Gorges Reservoir. The 380,000-m 3 sliding mass consisted mainly of cataclastic rock. A video record of the major sliding incident was analyzed using the general laws of physical motion. The analysis indicated that the maximum speed and maximum acceleration of the sliding mass were 11. 65 m/s and 2. 23 m/s 2, respectively, and that the maximum amplitude and the propagation velocity of the water wave near the landslide were 31. 8 m and 18. 36 m/s, respectively. Wave run-up investigation indicated that the maximum run-up on shore was 13. 1 m, which declined to 1. 1 m at Wushan dock 4 km away. The incident causes no casualties, but did result in economic losses of RMB five million. The numerical simulation model GEOWAVE was used to simulate and reproduced the impulse wave generated by the landslide; the results were in good agreement with the observed incident. The numerical simulation data were then applied to analyze the decay and amplification effects of the landslide wave in the river course. The field investigations and witness information provide valuable materials for the studies of landslide kinematics and impulse waves generated by landslides. In addition, the research results provide a useful reference for future similar waves generated by landslides in reservoirs. © 2012 Springer-Verlag.

Yin Y.,China Institute for Geo Environment Monitoring | du C.,Chongqing Institute of geological disaster prevention and control
Landslides | Year: 2016

On June 24, 2015, Hongyanzi slope located in Wushan County of the Three Gorges Reservoir collapsed, generating 5–6-m-high impulse waves, which overturned 13 boats, killed 2 persons, and injured 4 persons. It is the second incident of landslide-generated impulse waves since the 175-m experimental impoundment in 2008. The emergency investigation shows that Hongyanzi landslide is a bedding soil landslide with a volume of 23 × 104 m3 induced by a series of triggering factors such as rainfall, flooding upstream, and reservoir drawdown. The nonlinear Boussinesq water wave model is used to reproduce the impulse waves generated by the landslide of June 24th. The numerical simulation results suggest that the wave propagation process was influenced by the T-shaped geomorphic conditions of river valley, and the coastal areas in the county seat were the major wave-affected areas, which is opposite to the landslide. The numerical wave process accord well with the observed incident, and the investigation values were in good agreement with the calculated values. Moreover, the worst-case scenario of the 7 × 104 m3 deformation mass beside Hongyanzi landslide is potential to generate impulse waves, which was predicted with the same numerical model. This adjacent deformation mass will probably generate impulse waves with maximum height and run-up of 2.2 and 2.0 m, respectively, and only a very few areas in the water course had waves rising to a height of 1 m or above. The research results provide a technical basis for emergency disposal to Hongyanzi landslide and navigation restriction in Wushan waterway. More importantly, it pushes the risk management of the navigation based on the impulse wave generated by landslide. It is advised that the Three Gorges Reservoir and other reservoirs around the world should put more efforts in performing special surveys and studies on the potential hazards associated with landslide-generated impulse waves. © 2016 Springer-Verlag Berlin Heidelberg

Huang B.,Hubei Engineering University | Yin Y.,Hubei Engineering University | Yin Y.,China Institute for Geo Environment Monitoring | Jiang Z.,Yangtze River Scientific Research Institute
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2013

Impulsive wave events generated by landslides have the sudden and catastrophic characteristics, for which investigation information is very limited; so prototype physical experiment study is a good method in this condition. Taking impulsive wave event of Gongjiafang slump mass in Three Gorge reservoir area for the prototype, a big physical similarity model with the length of 24 m, width of 8 m, height of 1.3 m, is established, which is the first prototype model on main stream after the reservoir impounding. The model similarity ratio is 1:200. Marble grit(d50 = 1.47 mm) is used to simulate cataclastic rockmass in the test, using 15 wave gauges, high-speed cameras and run-up instruments to monitor wave process; and six sets of impulsive wave tests with the variable of impulse velocity into water in the front of the landslide are conducted. The comparison between test results and investigation results show that the test method can be used to study or forecast impulsive wave generated by similar cataclastic rockmass failure. After analyzing a series of test data, waves interactive process is showed firstly with the help of the gauge data, for example, wave chasing, superposition and reflection wave superposition. The data also finely portrait the wave propagation and run-up decay ratio in the riverway. Through this prototype model test, the improvement direction of the experiment on impulsive wave generated by cataclastic rockmass failure is discussed. The method used in this paper can offer references for impulsive wave generated by cataclastic rockmass failure, and the results obtained can provide great technical support for forecasting impulsive wave generated by other similar slopes of Three Gorges reservoir area.

Huang B.,Wuhan University | Yin Y.,Wuhan University | Yin Y.,China Institute for Geo Environment Monitoring | Jiang Z.,Changjiang River Science Research Institute | Liu J.,University of Wisconsin - Madison
Landslides | Year: 2014

Landslide-related impulse waves are catastrophic but accidental, so limited data on field measurements are available; scaled physical experiment is therefore a functional method to simulate and analyze this phenomenon. A large-scale physical Froude-similar model to produce impulse waves was constructed based on the Chinese Gongjiafang landslide, which occurred on the main stream of Three Gorges after the impounding in the reservoir in China. With a scale of 1:200, the model had the dimensions of 24, 8, and 1.3 m. Four water levels, 145, 156, 172.8, and 175 m, were modeled for the experiments, and marble coarse sands were used to imitate the actual cataclastic rock mass. Wave height gauges, high-speed cameras, and run-up measuring instruments were used to monitor wave fluctuations in the model. Among the experiments, the ones modeled using a water level of 172.8 m best confirmed the actual conditions in the Gongjiafang landslide, representing a good validation of the experiments. This study obtained, for the first time, specific data on the reproduced impulse waves' convergence and superposition during propagation, and of the energy change between impulse waves and reflected waves. The test data describe a rapid decaying and gradual decaying rule for the wave heights and run-ups. The Froude-similar experiments presented in this article help us to understand the whole procedure of impulsive wave generated by cataclastic rock mass failure, and the results acquired contribute to studies of impulse waves caused by similar bank destabilizations worldwide. © 2013 Springer-Verlag Berlin Heidelberg.

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