Seismic Stability Analysis And Reinforcement Measures Of High-core Rockfill Dams

Western China is rich in hydropower resources,and high earth-rock dams are also built here.At the same time,the western region is also a region with frequent earthquakes.In the Wenchuan earthquake,many earth-rock dams were damaged to varying degrees.Therefore,it is very necessary to conduct seismic research on earthrock dams in strong earthquake areas.The destruction of these earth-rock dams under the action of strong earthquakes mostly starts from the top of the dam.In order to improve the seismic stability of the dam body,reinforcement measures in the dam crest area have become the main means of earthquake resistance for high earth-rock dams.But at present,the research on the reinforcement mechanism of earth-rock dams is still relatively weak,and further research is needed.Taking the 300 m high clay core rockfill dam as the research object,the static and dynamic analysis of the reinforced rockfill dam under different reinforcement schemes is carried out through the finite element software,and from the two perspectives of dam slope stability and permanent deformation after earthquake To evaluate the seismic performance of reinforced rockfill dams,the main contents of the paper are as follows:(1)And through the finite element software,the static analysis of the rockfill dams under each reinforcement scheme.The results show that after the impoundment period,the reinforcement measures can reduce the deformation in the direction of the dam crest reinforcement.(2)In the dynamic analysis,the Hardin-Drnevich model considering the effect of confining pressure was compiled.The static stress state of each unit is extracted as the initial condition,and the dynamic analysis of the rockfill dam under each reinforcement scheme is carried out.The results show that the response acceleration,dynamic displacement,and dynamic shear strain of the dam body after the reinforcement measures are taken on the dam crest are all reduced,which has a positive effect on the seismic performance of the dam body as a whole.(3)The time-history stability safety factor of the dam slope with different reinforcement spacing and the permanent deformation of the sliding body after earthquake are calculated.The results show that the stability of the dam slope is significantly improved after reinforcement measures are taken on the dam crest.With the shortening of the reinforcement spacing,the position of the most dangerous sliding surface of the dam slope will move to the deep inside of the dam,and the smallest sliding surface The safety factor has been improved.The cumulative time with a safety factor of less than 1 and the permanent displacement of the sliding body gradually decrease,but the reinforcement spacing is too dense to improve the seismic performance of the dam body.By comparing the safety evaluation indicators under different working conditions According to the law of change,it is concluded that the optimal laying distance of geogrid is 3m.