| According to the statistics of the first national water conservancy survey,there are 6,180reservoirs in Shandong Province,of which more than 95%are earth dam reservoirs.The backslope area of earth dam reservoirs is about 69.6 km~2.According to the"Code for the Design of Rolled Earth-rock Dams for Small Water Conservancy and Hydropower Projects",the backslope of earth-rock dam reservoirs should adopt turf slope protection.Grass-slope slope protection not only requires higher maintenance costs,but also has poor ecological benefits.In the context of severe environmental pollution,how to tap the potential of land resources to maximize the benefits and improve environmental issues has become a hot science and technology issue.To this end,the paper takes the backslope of the earth-rock dam of the reservoir as the carrier,and uses perennial vine shrub honeysuckle as the research object to conduct the field test and numerical simulation of its hydrological protection and dam slope stability.The factors affecting the slope stability include internal factors and external factors.Internal factors are changes in the internal structure's own shear strength and weathering resistance under hydraulic erosion and erosion;external factors are earthquake damage,rainfall,and erosion of surface water,etc.,where rainfall is the induced dam slope The main external factors of instability.Therefore,in this paper,the erosion and sand production of honeysuckle covered and weed-covered slopes under different rainfall intensities were measured by the scouring tests on the backslope of earth-rock dams.The anti-scouring ability of honeysuckle slopes was studied.Using the SEEP/W and SLOPE/W modules in Geo-studio to simulate the dam slope pore water pressure and safety factor within 24 hours after the maximum 24h rainfall in 2017,2018,and 2019,respectively,and study the different slope protection forms against the dam.Impact of slope seepage prevention and stability.The main research conclusions are as follows:(1)The scour resistance test was carried out on the backslope of the earth dam.The results show that rainfall intensity and rainfall duration are important factors affecting the runoff and sand production behind the dam.Honeysuckle-covered slopes and weed-covered slopes both meet the greater rainfall intensity.Slope erosion runoff and sediment yield are greater;under the same rainfall intensity,with the increase of rainfall duration,the runoff and sediment yield of different slope protection forms gradually increase.(2)Under the same rain intensity conditions,the runoff and sediment yield of honeysuckle slopes are less than that of weed-covered slopes.The erosion damage of honeycomb-covered slopes is less.The erosion resistance of honeysuckle slopes is higher than that of weed-covered slopes..(3)Based on the SEEP/W seepage analysis,compared with plain soil-covered dam slopes and turf-covered dam slopes,the change in pore water pressure between 24h and 48h is smaller.It can be inferred that honeysuckle has higher water retention performance than turf and plains.earth.(4)Under the same rainfall conditions,the safety factors of dam slope covered by plain soil,honeysuckle and turf are compared.The results show that the safety factor of dam slope from high to low is:honeysuckle slope protection>turf slope protection>plain soil slope protection.Therefore,honeysuckle can improve the stability of dam slope,and its ability to improve stability is stronger than that of turf.(5)Based on the significant benefits of honeysuckle slope protection,and considering the economic benefits of honeysuckle,the possibility of application of honeysuckle on the backslope of earth dams was verified. |
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