截流缓释生态坝滤层设计研究OA

An interception and slow-release eco-dam is a soil and water conservation engineering measure that integrates geotextiles,sand and gravel,and willow stakes.And a reasonable filter layer design is significance for reducing operational and maintenance costs and improving project efficiency of dam.This study carried out orthogonal experimental with 3 factors and 3 levels,and the factors included permeability pressure(5,10 and 15 kPa),consolidation pressure(12,24 and 36 kPa)and muddy water concentration(3%,6%and 9%).The horizontal permeability coefficient and amount of clogging of filter body,the permeability and silt-clogging characteristics of comparative hierarchical combination and uniformly combined filter body were observed in the study process,and range analysis and sensitivity analysis were carried out.The results show that:①The horizontal permeability coefficient of the uniformly combined filter body with the range of 0.000 6～0.004 cm/s decreases monotonically with increasing permeability pressure,and increases at first and then decreases as consolidation pressure rises,and decreases at first and then increasing with higher muddy water concentration.With the increase of seepage pressure,consolidation pressure and turbid water concentration,the horizontal permeability coefficient of the layered composite filter body(0.001～0.006 cm/s)varies within a narrower range,resulting in minimal disruption to water flow through the dam body.② Range analysis indicates that the order of primary and secondary factors affecting the uniform composite filter was permeability pressure>consolidation pressure>muddy water concentration.However,for the layered composite filter,the order was muddy water concentration>consolidation pressure>permeability pressure.Sensitivity analysis further corroborates that the layered composite filter significantly mitigates the sensitivity of the horizontal permeability coefficient to changes in permeability pressure and consolidation pressure by leveraging complementary permeation mechanisms across its layers,and its sensitivity to muddy water concentration gradually decreases as the concentration increases.③The clogging rate of the layered(2.22%～3.14%)combined filter layer was moderately lower than that of the uniform filter(2.36%～3.25%)when the concentration of muddy water was 3%to 9%.The accumulated siltation volume in the layered composite filter was significantly less than that in the uniform filter during the long-term operation of the dam,which will improve the stability and extend the service life of the dam.The study confirms the effectiveness of the layered composite filter design and proposes a new filter configuration scheme for interception and slow-release ecological dams,thereby providing a scientific basis for their design.