Technical Center for Geological Hazard Prevention and Control

Chengdu, China

Technical Center for Geological Hazard Prevention and Control

Chengdu, China

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Ding W.-F.,Chongqing Jiaotong University | Ding W.-F.,Chongqing Jianzhu College | Zhou Y.-T.,Technical Center for Geological Hazard Prevention and Control | Zhou Y.-T.,Chinese Academy of Geological Sciences
Yantu Lixue/Rock and Soil Mechanics | Year: 2017

Based on the survey of Gongjiafang, Maoping and Shennüxi bank slopes, there are five stages of disintegration evolution of the quasi-earthy bank slope of Three Gorges Reservoir identified during impounding. These five stages are the formation of bank slope, the development of joint fissures, the formation of argillation interlayer and the quasi-bank slope, the disintegration of the bank slope by impounding, and the follow-up disintegration. On the basis of above disintegration evolution process, a physical model and a mechanical model are developed for the quasi-earthy bank slope disintegration from the viewpoint of fracture mechanics. The stress expressions and formulas of stress intensity factor are developed by considering five different working conditions at different storage levels in the mechanical model. Through the preliminary discussion, some conclusions are drawn as follows. The reservoir storage has a significant effect on the disintegration of the quasi-earthy bank slope. The stress intensity factor of rock block decreases with the increase of the water level. When the water level reaches a level of 4.49 m, fractures in the upper of rock block turn into the bottom, and the of stress intensity factor of rock block increases with rising water level. At the beginning of water storage, the development of fractures is dominated by the gravity of rock block, while the uplifting of water level stabilizes the rock block. The fractures controlled by gravity in the upper gradually change into the fractures governed by buoyancy in the lower part of rock block. The sectional dimension of rock blocks has the significant effect on the disintegration of the quasi-earthy bank slope. Fracture strength factors in the upper of rock block grow with the decrease of ratios of width to height; when the ratios of width to height decrease, fracture strength factors in the lower of rock blocks increase with the increase of the storage levels. © 2017, Science Press. All right reserved.


Zhang H.,CAS Chengdu Institute of Mountain Hazards and Environment | Zhang H.,CAS Institute of Remote Sensing | Zhang H.,University of Chinese Academy of Sciences | Wang X.,CAS Institute of Remote Sensing | And 5 more authors.
Remote Sensing | Year: 2015

The 2008 Wenchuan earthquake destroyed large areas of vegetation in the Baisha River and Longxi River basins, in Dujiangyan County, China. There were several debris flow events in these mountainous river basins after 2008. Currently, these damaged vegetation areas are in various stages of recovery. This recovery vegetation improves the resistance of slopes to both surficial erosion and mass wasting. We introduce a probabilistic approach to determining the relationships between damaged vegetation and slope materials' stability, and model the sediment and flow (hydrological) connectivity index to detect the hydrological changes in a given river basin, using the multi-temporal (1994-2014) remote-sensing images to monitor the vegetation recovery processes. Our results demonstrated that the earthquake-damaged vegetation areas have coupling relationships with topographic environment and slope material properties, and can be used to assess the slope material stability. Further, our analysis results showed that the areas with horizontal distance to river streams < 500 m are areas that actively contribute sediment to the stream channel network, and are main material sources for debris flow processes in one given mountainous basin. © 2015 by the authors.


Zhou Y.-T.,Technical Center for Geological Hazard Prevention and Control | Zhou Y.-T.,Chinese Academy of Geological Sciences
Yantu Lixue/Rock and Soil Mechanics | Year: 2016

The collapse of unstable rock is actually the problem of fracture and extension in dominant fissure of unstable rocks. Based on fracture mechanics model of dominant fissure, this paper puts forward a fracture stability determination method for unstable rocks, and establishing stability coefficient by the index of union stress intensity factor. By this method tip stress distribution forms of dominant fissure and its calculation expression are deduced. Fracture mechanism model of tip in dominant fissure for unstable rocks is proposed; and then for this calculation method union stress intensity factor in tips of dominant fissure is deduced. Fracture stability calculation results of unstable rocks in Shouli Mountain, Wanzhou Area, Chongqing show that the calculation results fit well with the field situation, so as to show that the fracture stability calculation method proposed is more security, objective and practical than the existing "specification method". © 2016, Science Press. All right reserved.


Zhang Y.,Technical Center for Geological Hazard Prevention and Control | Zhang Y.,Chinese Academy of Geological Sciences | Shi S.-W.,Technical Center for Geological Hazard Prevention and Control | Shi S.-W.,Chinese Academy of Geological Sciences | And 2 more authors.
Geological Bulletin of China | Year: 2013

With the large landslide disasters in Three Gorges Reservoir area as the study object, this paper has summarized and analyzed totally 72 control engineering projects used for tackling the disasters. The characteristics of prevention technology for large landslide disasters in the area are summed up. Through the analysis of the basic types and characteristics of the control engineering projects for the large landslide disasters in the Three Gorges Reservoir area, an evaluation index system for the control engineering measures against the large landslide disasters has been established, and the effects of the control project against the landslide disasters are classified in accordance with the evaluation index and standard.


Shi S.-W.,Technical Center for Geological Hazard Prevention and Control | Shi S.-W.,Chinese Academy of Geological Sciences | Liang J.,Technical Center for Geological Hazard Prevention and Control | Liang J.,Chinese Academy of Geological Sciences | And 6 more authors.
Geological Bulletin of China | Year: 2013

Aimed at solving the problem of gravel soil landslide slip along the bedrock surface, the authors studied the formation of the soil arching effect and the load-bearing mechanism under the condition of parallel arrangement of three rows of micro combined anti-slide pile reinforcement and according to the model test and finite element analysis. The result reveals the optimum distance-to-diameter ratio. As the result shows, in a certain load, the soil arching effect is first formed at the first row of micro-piles, and then with the increase of distance-to-diameter ratio, the soil arching effect is gradually formed at the second and third row; furthermore, load sharing ratio in the front row is significantly greater than that of the rear one. Soil arching effect is inconspicuous or non -existent when the distance-to-diameter ratio is less than 3 or greater than 11. The most ideal distance-to-diameter ratio is 7 and 8.

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