Large-scale Experimental Study On Contact Deformation Between Asphalt Concrete Core And Transition Material In Embankment Dams

At present,the asphalt core type embankment dam(ACED)has risen to the order of 150m,but there is still doubt about whether the dam industry will have a great impact on the safety of the core after the large shear deformation of the contact between the asphalt core and the transition material.To a certain extent,it has affected the development of high ACED.At present,there are few studies on this aspect at home and abroad and the research is not thorough enough.Therefore,this paper uses the newly developed large-scale stacked ring single shear instrument to conduct in-depth research on this problem through the original grading and large-scale model test,in order to provide tecthnical support for designing high ACED.The specific research contents and conclusions are as follows:(1)The single shear test of transition material shows that the relationship between shear stress and shear displacement is hyperbolic.The larger the axial stress is,the faster the growth rate of shear stress is,and the larger the peak value of shear stress is.The shear failure surface of transition material occurs in the area where the axial stress is the smallest.(2)The single shear test of asphalt concrete and transition material shows that the relationship between shear stress and shear displacement is hyperbolic.The larger the axial stress,the higher the distribution of shear stress-shear displacement curve.There is a good linear relationship between shear strength and compressive stress of specimens.(3)When shear deformation occurs between asphalt concrete and transition material,its dilatancy is related to the magnitude of axial stress.When the axial stress is less than 0.3 Mpa,the specimen shows dilatancy;when the axial stress is greater than 0.3 Mpa,the specimen turns to shear contraction.The development of horizontal displacement of each stacking ring during shear process indicates that there is no dislocation at the contact surface between asphalt concrete and transition material,and the location of shear failure surface is determined by the magnitude of axial stress.(4)After large shear deformation of asphalt concrete(270mm),the porosity of asphalt concrete in the whole asphalt concrete specimen is less than 3%except in the shear failure area(2-5cm)at the lower part of the specimen,especially in the vicinity of the contact with transition materials,which indicates that the asphalt core wall still has impermeability after large shear deformation.(5)After two kinds of small size sliding zone with thickness of 20 cm are set between the asphalt concrete core and the transition material,the sliding zone dissipates the locking effect of the transition material on the asphalt concrete core to a certain extent,and can effectively reduce the shear stress and strain of the asphalt concrete and the transition material after setting the sliding zone.