PRELIMINARY STUDY OF THE CREEP MECHANISM OF JINPINGZI ZONE Ⅱ SLOW MOVING LANDSLIDE IN LOWER REACHES OF JINSHA RIVER
JIANG Shu1, WANG Yifeng2, TANG Chuan3, PAN Hongyue2, WANG Kun2
1. Postdoctoral Research Station, China Three Gorges Corporation, Beijing 100038;
2. Wudongde Project Construction Department, China Three Gorges Projects Development Co., Ltd., Chengdu 610041;
3. State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059
Jinpingzi landslide is the nearest deep-seated colluvial debris landslide to the arch dam of Wudongde hydropower station in the downstream direction in lower reaches of Jinsha River. Its active zone Ⅱ was studied. Based on geotechnical investigation and long-term monitoring, the physical and mechanical property of the landslide materials and the long-term kinematics, especially the relationships among the landslide movement, rainfall and the groundwater were analysed. The response of the groundwater regime to the precipitation was further analyzed under different initial water content conditions based on the Green-Ampt infiltration model. Relationships between resisting forces and driving forces were discussed by limit equilibrium method assuming rigid-plastic frictional slip. Results showed that the long-term continuous movement was mostly due to the viscous component of the slip zone. Surface and subsurface displacement both showed a retrogressive type with average surface displacement rate 0.19~0.87mm·d-1 from 2005 to 2016. Basal sliding accounted for most of the deformation with different degrees of internal deformation in different parts. Rainfall was the predominant factor affecting the landslide activity but it is hard for rainfall water infiltrating to the deeply buried groundwater regime. Unlike some shallow landslides, the mechanism of Jinpingzi zone Ⅱ slow moving landslide was more likely to be the formation of transient saturated zone in shallow depth. The change of unit weight of the sliding mass and the effect of seepage affected the kinematics of the landslide.
. PRELIMINARY STUDY OF THE CREEP MECHANISM OF JINPINGZI ZONE Ⅱ SLOW MOVING LANDSLIDE IN LOWER REACHES OF JINSHA RIVER[J]. Journal of Engineering Geology, 2017, 25(6): 1547-1556.
Bertini T,Cugusi F,D'Elia B,et al. 1984. Climatic conditions and slow movements of colluvial covers in Central Italy[C]//IV International Symposium on Landslides.[S.L.]:Canadian Geotechnical Society:367~376.
Chen L,Young M H. 2006. Green-Ampt infiltration model for sloping surfaces[J]. Water Resources Research, 42 (7):887~896.
Corominas J,Moya J,Ledesma A,et al. 1999. Monitoring of the Vallcebre landslide, Eastern Pyrenees, Spain[C]//Slope Stability Engineering. Rotterdam:Balkema:1239~1244.
Corominas J,Moya J,Ledesma A,et al. 2005. Prediction of ground displacements and velocities from groundwater level changes at the Vallcebre landslide(Eastern Pyrenees, Spain)[J]. Landslides, 2 (2):83~96.
Dall'Olio L,Ghirotti M,Semenza E,et al. 1988. The Tessina landslide(eastern Pre-Alps, Italy):Evolution and possible intervention methods[C]//Proceedings of the 5th International Symposium on Landslide. Rotterdam:Balkema:1317~1322.
Editorial Committee of Engineering Geology Handbook. 2007. Engineering geology handbook[M]. Beijing:China Architecture and Building Press:158~162.
Fernández-Merodo J A,García-Davalillo J C,Herrera G,et al.2014.2D viscoplastic finite element modelling of slow landslides:the Portalet case study(Spain)[J]. Landslides, 11 (1):29~42.
Glastonbury J,Fell R. 2008. Geotechnical characteristics of large slow, very slow, and extremely slow landslides[J]. Canadian Geotechnical Journal, 45 (7):984~1005.
González D A,Ledesma A,Corominas J. 2008. The viscous component in slow moving landslides:A practical case[C]//Landslides and engineered slopes:from the past to the future. London:Taylor & Francis Group:237~242.
Hu G T. 1995. Dynamics of landslide[M]. Beijing:Geological Publishing House:105~130.
Huang S,Ding X,Zhang Y,et al. 2015. Triaxial test and mechanical analysis of rock-soil aggregate sampled from natural sliding mass[J]. Advances in Materials Science and Engineering, 2015:1~14.
Hutchinson J N. 1988. General Report:morphological and geotechnical parameters of landslides in relation to geology and hydrogeology[C]//Fifth International Symposium on Landslide. Rotterdam:Balkema:3~36.
Jiang S,Wen B P,Zhao C,et al. 2016. Kinematics of a slow-moving giant landslide in Northwest China:Constraints from high resolution remote sensing imagery and GPS monitoring[J]. Journal of Asian Earth Science, 123 (1):34~46.
Leonardo C, Michele C,Maria G G. 2014. Displacement trends of slow-moving landslides:Classification and forecasting[J]. Journal of Mountain Science, 11 (3):592~606.
Li G X. 2004. Advanced soil mechanics[M]. Beijing:Tsinghua University Press:238~270.
Massey C I,Petley D N,McSaveney M J. 2013. Patterns of movement in reactivated landslides[J]. Engineering Geology, 159 (12):1~19.
Nakamura H. 1984. Landslides in silts and sands mainly in Japan[C]//Proc. IV Int. Symp. On Landslides.[S.L.]:Canadian Geotechnical Society:155~178.
Picarelli L. 2007. Considerations about the mechanics of slow active landslides in clay[C]//Progress in Landslide Science. Berlin:Springer:27~45.
Ranalli M,Gottardi G,Medina-Cetina Z,et al. 2010. Uncertainty quantification in the calibration of a dynamic viscoplastic model of slow slope movements[J]. Landslides, 7 (1):31~41.
Sun P,Yin Y P,Wu S R,et al. 2009. An experimental study on the initiation mechanism of rapid and long run-out loess landslide caused by 1920 Haiyuan earthquake[J]. Journal of Engineering Geology, 17 (4):449~454.
Van Asch T W J,Malet J P,Bogaard T A. 2009. The effect of groundwater fluctuations on the velocity pattern of slow-moving landslides[J]. Natural Hazards and Earth System Sciences, 9 (3):739~749.
Van Asch T W,Van Beek L P H,Bogaard T A. 2007. Problems in predicting the mobility of slow-moving landslides[J]. Engineering geology, 91 (1):46~55.
Varnes D J. 1978. Slope movement types and processes[C]//Schuster R L., Krizek R J. Landslides, Analysis and Control, Special Report 176. Washington, DC:Transportation Research Board, National Academy of Sciences:11~33.
WP/WLI. 1995. A suggested method for describing the rate of movement of a landslide[J]. Bulletin of the International Association of Engineering Geology, 52 (1):75~78.
Xu Y H,Xu Q M,Yang D Y,et al. 2006. Formation and geological setting of the accumulations in Jinpingzi reach of the Jinshajiang river[J]. Quaternary Sciences, 26 (3):429~435.
Yan F Z,Wang S J,Xu R C. 2003. Deformation mechanism and development tendency of Maoping landslide after impounding of Geheyan reservoir on Qingjiang river, Hubei province, China[J]. Journal of Engineering Geology, 11 (1):15~24.