Damage Analysis Of High Arch Dam Considering The Field Of Transverse Joint

Arch dam has the advantages of thin shape,saving building materials,strong bearing capacity,good economy which result in a high selection rate in Southwest China where is rich in hydropower resources.But Southwest China is located in the Eurasian earthquake zone,which is a region with frequent earthquakes.Therefore,the seismic problems of arch dams are particularly prominent.The earthquake damage examples of arch dams in history show that the seismic performance of arch dams is excellent,but these examples are only limited to lower arch dams,and there is no earthquake damage example of high arch dams.So arch dam is chosen for its outstanding overload capacity and materials nonlinear under cyclic tensile-compressive load as well as the initial stress field formed during the construction of high arch dams before earthquakes.The additional mass method is also used into analysing the damage and cracking of high arch dams under natural seismic wave spectrum characteristics.At the same time,because of the particularity of the transverse joint of arch dams,if the transverse joint is considered,the overall rigidity of the dam will be weakened,and the nonlinear contact between the transverse joints will affect the damage area of the arch dam under the earthquake load.Based on the plastic damage research of the dam material,the arch dam is divided into different dam sections,and the damage and cracking analysis of the arch dam under the nonlinear contact of the transverse joint is considered.The main tasks of this study are:(1)The dam-foundation-reservoir water coupling system is established due to the study of design data.Based on the characteristic water level of design data,the modal research is desiged out different experiment mode such as no water,dead water and normal water level,which is compared with the results of finite element model of Laxiwa arch dam calculated by previous scholars.And the fundamental frequency difference under dead water level is 1.18%.The small difference from previous experiments indicates the accuracy of the model and the accuracy of the parameter selection.At the same time,each mode at different characteristic water levels also decreases with the increase of the water level in front of the dam.(2)In view of the non-linearity of stress-strain softening of dam concrete under ultimate load,a reasonable non-linear plastic material constitutive model is selected.Based on the original design data,the tensile and compressive strength of dam concrete under the corresponding grade is determined,and the material parameters used for calculation are determined according to the specifications.The corresponding seismic waves are chosen based on dam site characteristics and seismic grade of structure.After calculation different working conditions,the results are compared with previous model tests.The results of dam damage are similar to those of previous model tests concerning the damage and cracking of weak parts of the dam.(3)Based on the previous study,the transverse joints are set in the dam body,and the modal comparison analysis prove that the integrity of the structure is influenced.Meanwhile,compared to the previous experiment design,it is concluded that the middle part of the arch crown is still the weak part of the dam body,and the opening and closing differences of the transverse joints under the seismic load are also the coupling material nonlinearity factors and the contact factors of transverse joints.