Dynamic Characteristics Of Red Soil In The Core Wall Of The Daqing Reservoir Dam In Dayao County And Seismic Simulation Of The Dam Body

Core-wall earth-rock dam is a type of dam widely used in reservoir projects.Choosing appropriate core-wall anti-seepage materials is very important to the anti-seepage and safety and stability of earth-rock dams.Red soil is widely developed in more than a dozen provinces and regions,including Yunnan,Guizhou,and Guangxi.It is of great significance to make full use of local red soil as the core wall impermeable material of earth-rock dams.Due to the special nature of the laterite engineering,the seismic load is more destructive to the laterite,which will reduce the strength of the laterite in the core wall,thereby endangering the safety and stability of the earth-rock dam.Therefore,the systematic in-depth study of the seismic characteristics of red clay core dams under seismic loads has very important theoretical value and practical significance for further promoting the construction and development of red clay core earth-rock dams.Through experimental research and numerical simulation methods,this paper mainly uses dynamic triaxial tests to test the dynamic elastic modulus,dynamic shear modulus,damping ratio and dynamic strength characteristics of sandstone residual red soil under different confining pressures and consolidation ratios.Experiments show that under the conditions of different confining pressure and consolidation ratio,the dynamic stress-strain curve grows nonlinearly,and the dynamic strain is positively correlated with the consolidation confining pressure and consolidation ratio;the dynamic elastic modulus is as the strain increases.The nonlinearity decreases,which is negatively related to the consolidation confining pressure and consolidation ratio;the dynamic shear modulus decreases rapidly with the increase of dynamic shear strain at the beginning of loading.After loading to a certain extent,the dynamic shear modulus decreases rapidly.The change rate of modulus slows down and eventually tends to a stable value;under the conditions of different consolidation confining pressure and consolidation ratio,the damping ratio increases nonlinearly with dynamic shear strain,and is positively correlated with the consolidation confining pressure and consolidation ratio.The dynamic strength curve and the relationship between the failure vibration frequency and the dynamic strength index show that the dynamic internal friction angle and dynamic cohesive force decrease nonlinearly with the increase of the number of vibration failures.Finally,according to the results of the dynamic characteristics test and engineering examples,the MIDAS GTS finite element software is used to perform static and dynamic finite element calculations for the sandstone residual red clay core wall dam.The stress and strain conditions of the dam body and core wall under seismic loads are mainly studied.By applying seismic loads in different directions to the dam body,it is concluded that under the action of the seismic load,the top deformation of the dam body is the largest,which is the weak part of the seismic performance of the dam body.It is necessary to strengthen the support during the design and construction to improve the seismic resistance of the dam crest.performance.