Analysis Of Mechanical Characteristics Of Compacted Asphalt Concrete Core Dam In Tibet

Roller-type asphalt concrete core wall dam is widely used in the world,is also one of China's vigorously promote a dam type.Asphalt concrete core wall has good ability to adapt to deformation,seismic performance,erosion resistance,anti-aging ability and the overall need to set the advantages of structural joints,therefore,can be used in any climatic conditions and any altitude.Theoretical analysis and engineering practice have shown that the safety of asphalt concrete core dam is a kind of great development potential dam type.The mechanical properties of roller compacted asphalt concrete core dam are the focus and hotspot of research at home and abroad.In order to verify the safety and rationality of dam structure,it provides the basis for structural design and optimization design of dam body.The stress deformation characteristics of roller compacted asphalt concrete core sand and gravel dam need to be further studied.Based on the principle of finite element calculation,the three-dimensional nonlinear finite element static and dynamic calculation and analysis of asphalt concrete core sand and gravel dam are carried out to study the ultimate earthquake resistance and the seismic measures are put forward.The main conclusions are as follows:(1)Heart wall stress along the dam was parabolic distribution,two small,middle large,and the heart wall stress is greater than the transition layer on both sides,the core wall "arch effect" is not obvious.A large number of experiments show that the basic mechanical properties of asphalt concrete obtained by actual rolling are low and the modulus K is usually between 200 and 400.It is shown that when the K is 100,which is smaller than the actual lower limit,the core wall has obvious "Arch effect";when K take 200,the heart wall "arch effect" basically disappeared.(2)The depth of suspension of the impervious wall has a great influence on the whole seepage characteristics of the project,and the sensitivity analysis is carried out for the different depth of the cutoff wall.The results show that with the increase of the depth of the suspension,the permeability of the dam decreases gradually,and the permeability ratio of the core wall and the cutoff wall gradually increases,and the total seepage flow of the dam body is gradually reduced.Wall and cut-off wall of the penetration ratio are smaller.The depth of the suspension should be optimal under the requirement that the penetration ratio meet the allowable slope requirements.(3)The maximum hydraulic slope in the asphalt concrete core wall is much smaller than the allowable hydraulic slope,the possibility of occurrence of osmotic deformation is small;the maximum hydraulic slope of the anti-seepage curtain is also within the allowable range,but as a concealed project,Its construction quality control;dam the rest of the parts of the maximum hydraulic slope of the fill are less than the allowable value,the possibility of occurrence of osmotic damage is small.