Study On Stress Strain Characteristics Of Asphalt Concrete Core Wall Under High Stress

The asphalt concrete with the core wall is widely used in the hydraulic engineering because of its good performance of anti-seepage,strong ability to adapt to deformation and a certain healing ability.In recent years,a large number of Xinjiang asphalt concrete core dam was built and used,the dam has become one of the important type of dam in hydraulic engineering.With asphalt concrete core wall dam in the application of more and more mature,the construction of the dam development in the direction of the high dam.Under the direction of increased in the dam height,the parameters of the asphalt concrete on the dam should influence degree of stress and strain needs further research and analysis.In this research,the stress-strain properties of asphalt concrete under different confining pressures are measured and analyzed according to the test results of the static three axial tests.According to the height of the dam and the effect of the water load,the static three-axis parameters of asphalt concrete are divided into two parts.On this basis,the finite element software ABAQUS is used to calculate the stress-strain of the dam,through the experimental study on the above,the main conclusion as following:(1)Through the triaxial shear test analysis of asphalt concrete under confining pressure 2.0MPa?axial strain 20%,the results show that the aggregate does not break after the high confining pressure and large strain test,that in the asphalt concrete core wall dam,when the vertical settlement or horizontal displacement occurs in the core wall,the aggregate is still the main bearing of the force,the aggregate will not break,and the gradation of asphalt concrete will not change.(2)Elongated particles increase has certain influence on the mechanical properties of asphalt concrete,liquidity and reduces the asphalt concrete;at the same time elongated particles has a certain impact on the asphalt concrete porosity,resulting in the increase of permeability coefficient,the anti-seepage performance decreased.(3)Three axis can be obtained through static test,asphalt concrete specimens after the test compared to before the test specimen porosity increased slightly,asphalt concrete obvious dilatancy;shear zone porosity is far greater than the whole sample porosity;if the dilatancy damage will reduce the anti-seepage performance of asphalt concrete.(4)With the increase of confining pressure,deviatoric stress of asphalt concrete is gradually increasing,but the growth has slow trend.According to the trend line formula of confining pressure and deviatoric stress,obtained under 2.48 MPa ideal plastic form,the axial strain reached 17.1%.(5)When the model parameters are calculated,the results of the calculation under low confining pressure and high confining pressure are different,the internal friction angle,modulus coefficient K,cohesion c,modulus index n showed a regular change trend.(6)Through the finite element calculation: low stress area,middle stress area and high stress zone of different asphalt concrete under static static three-axis parameters,degree of influence on the stress and the strain of the whole dam body parts is very small.Through the finite element calculation: Under the action of the water load,the stress of the core wall increases with the increase of the low stress zone to the high stress area,and the stress of the core wall decreases with the low stress zone to the high stress area,and the change of the stress is slightly improved.Under the same conditions of rockfill material and transition material,the static three axial parameters of asphalt concrete have certain influence on the stress strain of the core wall,but not very significant.