Analysis On Leakage Of Shuanglong Karst Dissolution Reservoir In Earthen Area Of Southwest Guizhou

The southwest Guizhou is a typical karst mountainous area in China.The proposed Shuanglong Reservoir is located in ZheXiang Town,Zhenfeng County,Guizhou Province.In the two erosive depressions of Luozhang and Poha,it is proposed to block the underground karst channel and suspicious leakage,The formation of medium-sized dam without dam reservoir depression,storage capacity of about 2000 × 104m3.The study area has a strong intermittent uplift since the Quaternary period,forming a large-scale development of eroded platform landforms,dissolution depressions and karst troughs with three dissolution planes.The reservoir is from the west to the east with the platform facies,the edge of the platform and the basin over the belt with the characteristics of the reservoir south of the north side of the northern plateau for the regional erosion datum,a strong role in the reservoir area suspended above the two level,And the valley elevation difference of nearly 700 m.Coupled with the near EW fault,NW joint joints and interlayer erosion fracture of the role of water conduction,so that the reservoir area where the river water unit in an open state,and the surrounding karst hydrological geological unit closely linked.Has been identified 157 karst collapse and falling water,K?and K?5two large underground karst channel in the reservoir area.The geological problems of reservoir karst leakage are very serious.Based on a large number of regional geological data and feasibility study report,this paper analyzes the characteristics of karst development in Shuanglong reservoir area and the water richness of various water-bearing rock groups through more detailed engineering and field investigation,laboratory analysis and calculation And the characteristics of karst water development,the characteristics of karst water system and the influence of karst hydrogeological conditions on reservoir leakage,and forecast the hydrodynamic forces of reservoir leakage.Conditions and the characteristics of the leakage medium,the feasibility of the reservoir seepage control design,and puts forward the suggestions of the optimal design of the reservoir seepage control project.This phase of the study mainly obtain the following understanding:(1)The characteristics and regularity of karst landforms: Since the Quaternary in the study area,the crust has been uplifted and the Beipanjiang has deepened anddeveloped from the east to form a three-level eroded terrace.The depth of the depression from the deep depression to the shallow depression,and even the karst plains,is the same as that of the karst slopes,The development direction of the depression is mainly northward,followed by the northwest.(2)Karst hydrogeological conditions: the study area is located in the zhexiang karst hydrogeological units,according to the terrain and excretion characteristics,and further divided into six secondary hydrogeological units..A large number of sinkholes were developed in the reservoir area,and two main karst leakage channels named K??K?5were found.which leakage type are scattered and concentrated.The karst layer type is dominated by T1a1 and T1a2 continuous dolomite aquifers,and the formation of relatively uniform fissures and heterogeneous pipelines is formed under the influence of fault.From the vertical dissolution of the reservoir area,we can see that there is a layer of relative aquifer in the reservoir area around 937 m,and there is no direct hydraulic connection between the two layers.The reservoir area is not directly related to the Beipanjiang River on the south side of the south,and the strong height difference will not form the natural hydrodynamic condition of the reservoir.(3)Reservoir seepage evaluation: the groundwater level is higher than the reservoir normal water level,the groundwater recharge reservoir,the groundwater recharge reservoir,the groundwater recharge reservoir,the groundwater recharge reservoir,the reservoir water level,There is no possibility of reservoir leakage between the southwest bank and the dam bridge hydrogeological unit,there is no leakage may be,but the water level of the watershed is low,it is suggested that the next stage of work should be further evaluated.There is a low o Valley-Yinhe River on the north shore of the reservoir,which is the main leakage area of the proposed reservoir.The leakage channel is mainly concentrated with pipeline leakage,and the maximum leakage is 3.22 × 105 m3 / d.The south shore of the reservoir is limited by the weak karst developmental layer,and the groundwater of Luobei and Poha Hazi has no direct hydraulic connection with the southwest measured groundwater.In the wet period and the reservoir under normal conditions of water storage,the groundwater has over the slow,thin groundwater watershed or potential karst pipeline to the depression 6 direction,on the direction of the direction of the winter,the possibility of leakage of stone wall,Gap leakage,the maximum total leakage of 8.50 × 104m3/ d.(4)Key anti-seepage program: combined with the possibility of reservoir leakage assessment,through the anti-seepage line preliminary comparison,it is recommendedto use the program as a barrier curtain line.In the program one,in addition to ZK101 to the northeast of 260 meters to ZK102 to the south about 50 meters above the water level of the watershed,the rest of the sections need to do anti-seepage treatment;through the water pressure test data analysis,this The study suggested that 3 Lvong line as the bottom of the barrier,and the reservoir section of the karst leakage pipeline for centralized closure.(5)In this paper,three-dimensional numerical analysis method is used to simulate and analyze the groundwater seepage field under three different working conditions according to the natural seepage field,the reservoir water storage and the anti-seepage curtain.The leakage amount of the reservoir The total leakage of the reservoir area was 428619.35 m3 / d under the condition of water storage,and 669.99 m3 / d in the reservoir area under the condition of seepage control,and the feasibility of the anti-seepage treatment scheme was verified.