Study On Stability Of The Bank Slope Of Pingliang Reservoir In Gansu Province

With the development of economy,reservoir is an important water conservancy project,plays a more and more prominent role in flood control,comprehensive utilization and economic development.Kongtong reservoir is located 12 kilometers below the western suburb of Pingliang,Gansu.It was built and put into use in 1980.The total capacity of the reservoir is 2970×104 Cubic metres.It is a medium-sized reservoir with comprehensive benefits of flood control,water supply,power generation and tourism.The reconstruction and expansion project of Kongtong reservoir is imminent to alleviate the demand for water use in the Kongtong city and to solve the problem of the shortage of water for agricultural irrigation in the lower reaches of Ningxia from the upstream.Before the implementation of the project,the stability analysis of the reservoir bank slope is carried out to prevent the serious damage caused by the slope instability.It has important reference value to the quality of the project construction of the reservoir,and it is of great significance to maximize the comprehensive benefit of the reservoir.On the basis of reviewing a large number of documents and summarizing the study of reservoir bank slope at home and abroad,the field investigation,test analysis and slope stability calculation are carried out on the bank of Kongtong reservoir.The results of the study show that:(1)The geological conditions in the area of Kongtong reservoir are more complicated.The Kongtong Reservoir is located at the east of six Panshan Mountain,the eastern part of the south section of the East Foot Fault zone of the north of the thrust-nappe structure,which is more serious in terrain cutting and staggered in fault zone.It provides favorable conditions for the formation and development of landslides.(2)There are 7 landslide bodies on the bank slope of Kongtong Reservoir: Drilling data and laboratory tests show that there are 2 small landslide bodies on the left bank of the reservoir area,namely the lower part of the uterus and the downstream landslide body;There are 5 landslide bodies on the right bank,namely the West landslide of the flat slope village,the left landslide of the flat slope village,the old landslide in the flat slope village,Han Jia landslide body and Han Jia East landslide body.(3)The slope of the bank of Kongtong Reservoir tends to be stable.According to the geological analysis of the reservoir area,the overall stability of the bank slope is better.From the analysis of the stability parameters of the left and right side landslide bodies and the left and right abutment,the downstream landslide body,the lower uterus landslide body,the Western landslide body of the flat slope village,the landslide body on the flat slope,the old landslide in the flat slope village,the landslide body of the Han Jia Wan Village and the east of the Han Jia Wan are 1.55,1.87,1.282 1.03,1.35,1.218 and 1.55.Among them,the landslide on the left side of the flat slope is in the limit equilibrium state.Due to its small volume,the impact on the reservoir can be neglected,and the rest of the landslide is in stable state.(4)Based on the characteristics of the Kongtong reservoir and the characteristics of the landslide,specific control measures are put forward.In order to ensure the stability of the bank slope of Kongtong Reservoir,six aspects such as eliminating surface water in landslide area,dredging and guiding underground water,preventing erosion of reservoir water,cutting slope,improving nature of rock mass of slope and building supporting block were put forward.Through the exploration test and calculation analysis,the paper hopes to provide the reservoir slope stability status for the reconstruction and extension project of Kongtong Reservoir.As the necessary numerical and planning considerations for the project construction,and also provides the important reference for other hydraulic engineering construction.