Sliding Phenomena in High-Mountain Conditions
Prediction of the Sliding Phenomena on the Basis of Analysis of Mechanisms of a Failure of Natural and Artificial Slopes in High-Mountain Conditions of Kyrgyz Republic
Tech Area / Field
- OBS-NAT/Natural Resources and Earth Sciences/Other Basic Sciences
- ENV-MRA/Modelling and Risk Assessment/Environment
- ENV-SEM/Seismic Monitoring/Environment
8 Project completed
Senior Project Manager
Kirichenko V V
Kyrgyz-Russian Slavonic University, Kyrgyzstan, Bishkek
- Institute of Seismology, NAS, Kyrgyzstan, Bishkek
- Universita degli studi di Milano-Bicocca / Department of Geological Science and Geotechnologies, Italy, Milan\nLawrence Livermore National Laboratory / Environmental Science Division, USA, CA, Livermore
Project summaryThe aim of project is the analysis of processes of formation of active landslides on natural and artificial slopes in high-mountainous climatic, geological and tectonic conditions of Issyk-Kul Depression and its mountain surrounding in Kyrgyz Republic.
The aim can be reached by a study of the rock masses on the chosen test grounds located at the same geomorphologic, tectonic and climatic conditions; by of mathematical modeling of landslide formation for concrete conditions; by numerical modeling of stress-strain condition of the rock massifs; by monitoring for mass displacement on the basis of air photography and ASTER satellite images, and also by creation of a system of an estimation of stability of rock slopes for prediction of their failure.
Failure of natural and artificial slopes. A problem of maintenance of stability of artificial quarry slopes become more and more actual in tie with a deepening of working opencasts and with execution of large-scale mine-technical exploitation in high-mountain conditions. For example, in 2002 on Kumtor quarry (central Tien Shan) there was a failure of benches of volume more than 1 million cubic meters which have entailed human victims and significant economic damage.
About 40 % of territory of Kyrgyz Republic is undergone by influence of natural sliding processes. So, for example, in 1994 under a landslide at village Tosoy (Uzgen region in the south of Kyrgyzstan) 50 people were killed. In Komsomol village (in the same area) the landslide became a grave for 28 men. In April 2003 the landslide at Kara-Taryk village of Uzgen region of the Osh oblast' has resulted in death of 34 people and significant destructions.
Unfortunately, the processes of landslide formation in Kyrgyz Republic are insufficiently investigated. The numerous models offered earlier explaining mobility of landslides (Kent 1966, Grigoryan 1979, Erismann 1979, 1986, Melosh 1979, Davies 1982, Campbell 1989, Melosh, 1979, 1983, 1986, Shaller, 1991, Xiaoning 1991, Kobayashi 1993) do not take into account all known features of their morphology and internal structure (Strom, 1994, 1996, 1999). Therefore problem of analysis of the mechanism of landslide formation has not been solved yet (see for example, Erismann 1986).
Definition of general regularities and distinctive features of landslide formation on natural and artificial slopes is necessary for solution of this problem.
Large rock slide of the volume of some millions cubic meters located upslope Tossor village, Issyk-Kul Oblast' and Kumtor quarry of the same region have been chosen as test grounds. There will be studied also significant land- and rockslides in the Chon-Kyzyl-Suu river valley in the Issyk-Kul Oblast'.
The landslides can be activated in case of their essential watering during a rainy period or an earthquake of moderate seismic intensity (I=5-7) that can be resulted in numerous victims among the population and significant economic damage.
The choice of these objects was based on that the similar gravitational deformations are abundant all over Tien Shan, and methods of their analysis are developed during previous studies which have been carried out by the participants of the project (KRSU and KIS) (Korjenkov, 1997, 2006; Korjenkov and Charimov, 1993; Korjenkov and Chedia, 1986; Korjenkov et al., 1994, 1999a, b; Usmanov and Buruchenko, 2000; Usmanov, 1999).
Complicated climatic conditions are the key factor of landslide formation in Kyrgyzstan. It is supposed to conduct estimation of climatic factor effect on failure of natural and artificial slopes from the data of Hydrometeorological Servey of Kyrgyzstan.
Analysis of morphology of sliding bodies and scars will be carried out on the basis of detailed aerial imagery available at KIS archive. The data were unavailable formerly to a wide range of researchers in view of their secrecy. However, nowadays their use is possible for the chosen test grounds.
The technique of field observations and their processing allows obtaining operatively of many parameters on the cross section, including structural parameters, at rather complex geological conditions: wave screens, inclined boundaries, ruptures. That is why this type of works is highly profitable both from the point of view of obtaining the wide information of landslides, and expenses of time and finance for obtaining these data. The study stated above will be conducted in particularly at use of laser total station available in KIS.
Topographic monitoring of landslides will be carried out by laser total station, and their internal structure - by known engineering-geologic methods. These studies will allow decision of the following tasks: 1) definition of structure and thickness of landslide accumulations and slope zone of weathering and unloading; 2) study of parameters of physical and mechanical properties of landslide accumulation of still undetached rocks with the purpose of future use for stability calculations; 3) determination of basic characteristic of stress-strain conditions of rocks of landslide slopes for analysis of their time variations.
Modern level of development of measuring and computing means, geomechanical models and methods of monitoring of rock massif allow usage of the modern approach to solution of problems of stability estimation large rock exposures. Calculation of stress-strain state of a rock massif by the method of final elements is in the basis of software complex.
The data of conditions of rock massifs supposed to be obtained using automatic control system of rock massif movement and information of satellite imagery. It is supposed to use ASTER satellite images having resolution of 1 pixel x 15 meters. This system will allow proving the adequacy of the geomechanical model to real processes of rock massif destruction.
Tasks of the project:
Decision of the following tasks is supposed for achievement of the project aim:
- Study of morphology and internal structure of scars in benches and tails of Kumtor quarry and natural rock slide located upslope Tossor village as well as significant rock and landslides in the Chon-Kyzyl-Suu river valley, Issyk-Kul Oblast';
- Creation of system of information collection and transmission on the basis of selected technical and soft ware (peripheral stations, communication apparatuses with dispatching center, receivers of dynamic characteristics of rocks etc.).
- Study of destruction processes of rock massifs in natural scarps and landslides on the chosen test grounds.
- Selection of geologic, topographical, geodynamic and climatic factors promoting formation of landslides both on natural and artificial slopes which can be used as a basis of landslide hazard assessment.
- Development of geomechanical models of landslide formation for the chosen polygons, and revealing similarities and distinctions of landslide formation on both natural and artificial slopes which can be used for the landslide hazard assessment.
- Determination of criteria of slope stability for the rock slide upslope Tossor village as well as significant rock and landslides in the Chon-Kyzyl-Suu river valley, bench massifs of Kumtor quarry, Issyk-Kul Oblast'. Development of recommendations for similar objects in territory of Kyrgyzstan for reduction of landslide hazard.
Realization of the project will allow achievement of the following results:
- Internal structure of scars and landslide bodies of mountain slopes located upslope Tossor village, significant rock and landslides in the Chon-Kyzyl-Suu river valley as well as bench massifs Kumtor quarry, Issyk-Kul Oblast', will be studied;
- Similarities and distinctions of failure mechanisms for both natural and artificial slopes of the chosen test grounds located at identical climatic, geomorphological and geological-tectonic conditions will be revealed;
- Geomechanical models of landslide formation on both natural and artificial slopes in Issyk-Kul depression will be developed;
- Landslide hazard assessment of studied areas will be carried out, and measures for landslide hazard reduction will be developed;
- Recommendations for strengthening of landslide slopes or evacuation of population from dangerous zones will be elaborated.
- Identification criteria of basic initiators of failure of rock masses will be developed and their hazard will be assessed;
All the obtained assessments and recommendations will be passed to the Ministry of Ecology and Emergency, the Ministry of Building and Architecture after the project implementation.