Analysis Of Dynamic Response And Stability Of Earth-rock Dam In Hezhuang Reservoir

The reservoir dam type built in North China is mainly composed of earth and rock structure dam in low reservoir area with low dam height.The seismic belt in this area is widely distributed,and the seismic performance of earth-rock dam materials is poor.It is necessary to conduct seismic research on it.The quasi-static method is generally used for seismic stability calculation of earth-rock dams.However,this method does not consider seismic characteristics,and does not consider the dynamic and damping properties of dam materials.It cannot directly reflect the local and overall damage of the dam.In order to obtain a reasonable seismic calculation result of earth-rock dam,this paper uses nonlinear numerical analysis method to calculate the dynamics of the earth-rock dam in Hezhuang Reservoir,and simulates the dynamic response of the dam under different seismic loads from local stability and overall stability.Two aspects of the stability analysis of the dam.The main contents of the paper are as follows:(1)Using the acceleration as the core,the nonlinear response analysis method is used to analyze the dynamic response of the dam.The nonlinear analysis method can comprehensively consider the influence of different factors on the local and global damage of the dam,and its simulated dynamic response process can be closer to reality.The calculation results show that the acceleration response of different positions the dam is different,and the acceleration value increases with the increase of the dam height.The acceleration magnification decreases with the increase of the peak acceleration in the input seismic wave.The acceleration of the dam body input into the seismic wave in different directions is basically consistent.When a strong seismic load is input(9 degrees),the dam body is destroyed,the internal stress is redistributed,and the maximum value of the maximum principal stress and the minimum principal stress is changed.The horizontal displacement of the dam is greater than the vertical displacement.Both displacements are gradually increased along the dam height.(2)Based on the local stability evaluation method,the stability analysis of the post-earthquake dam is carried out.The dam will cause local damage under the action of seismic load to affect the overall stability of the dam.The stability evaluation contents include: calculation of dam crest,shale unit seismic stability calculation,anti-seepage safety evaluation and liquefaction possibility discrimination.The results of the above four aspects show that when the strong seismic load is input(9 degrees),the dam cresting rate exceeds the corresponding safety evaluation index,and the large-scale unit seismic stability safety factor of the upper and lower dam slopes is less than 1.The body is broken through.The dam and foundation are not liquefied.Considering the extent of local damage,the local damage of the dam has an impact on the stability of the dam.(3)The seismic safety evaluation of the dam slope is carried out by using the dynamic timeline method and the dynamic equivalent method.The safety factor calculated by the dynamic timeline method reflects the dynamic change process of the earthquake with the time of the earthquake,and the safety factor calculated by the dynamic equivalent method is the total safety factor of the dam slope under the earthquake load.The above two methods are used to calculate the anti-sliding stability of the dam slope.The results show that when the strong seismic load is input(9 degrees),the safety factors of the anti-sliding stability of the upper and lower dam slopes calculated by the two methods are less than the corresponding safety.Evaluation indicators,the dam body produced sliding damage.By combining the safety factors calculated by the above two methods,the seismic safety of the dam slope can be judged.