| Compared with the traditional retaining wall structure,geogrid-reinforced retaining wall has been widely used in roads,ports,dams and foundation treatment projects due to its small footprint,convenient construction,low cost and beautiful structure.However,as a flexible retaining structure,the study on the seismic mechanism of geogrid-reinforced soil retaining wall is not thorough.Sand is usually used in geogrid-reinforced filling,but the national environmental protection policy is tightened,sand and gravel materials are increasingly scarce.It is necessary and urgent to seek a new type of backfill.As waste steel slag and waste tires for industrial waste,aged steel slag and waste tire rubber particles can be used for geotechnical backfilling.Therefore,the shaking table test of seismic performance of geogrid-reinforced retaining wall is carried out with waste steel slag,waste tire rubber particles and mixture of steel slag and rubber particles respectively as backfilling in this paper.Specific research contents are as follows:(1)The working principles of SY70L-2.5 hydraulic shaking table,UT3416FRS-DY dynamic data acquisition system and UT7832 dynamic strain data acquisition system were introduced.The boundary effect of laminated shear model box was tested and analyzed by steel slag material and shaking table.The physical and chemical properties and mechanical properties of steel slag,tire particles and geogrid material were introduced.(2)Shaking table test model of geogrid-reinforced retaining wall was designed according to Froude constant in dimension analysis theory and principle of similarity ratio.The processing method of random seismic waves,the comparison method of target spectrum and control spectrum in shaking table test were introduced.The loading conditions of geogrid-reinforced retaining wall model test were designed and various sensors were selected.(3)Considering the influence of near and far site seismic waves and seismic intensities on steel slag backfilling,the response laws of geogrid-reinforced retaining wall under different seismic waves and intensities were studied,including wall displacement,horizontal acceleration,backfill acceleration,vertical settlement of backfill surface and dynamic strain of geogrid,etc.The seismic response of the reinforced wall with traditional sand as backfill was compared to explain the different reasons of seismic response from the mechanism.(4)Shaking table model test was carried out for rubber particle backfilling,and the seismic response of reinforced wall with steel slag and traditional sand as backfilling was compared.It is concluded that steel slag and rubber particle have their own advantages and disadvantages when they are used as backfilling of geogrid-reinforced retaining walls respectively.The acceleration amplification effect of seismic wave on reinforced walls can be effectively weakened by heavy steel slag.And the lateral deformation of the reinforced wall and the settlement of the filling surface can be also effectively reduced by light rubber particles.(5)Three types of steel slag and rubber particles with different proportions were selected as new mixed geo-filler to carry out shaking table model tests of geogrid-reinforced retaining wall with new geo-filler under different rubber particle mixing ratios.Compared with the seismic response of steel slag,rubber particles and traditional sand backfill,it is shown that the retaining wall filling with better seismic performance can be obtained by mixing steel slag and rubber particles in proportion,and the proportion of geogrid-reinforced retaining wall can be adjusted according to the requirements of different projects to form a new type of geo-filler instead of sand. |
PDF Full Text Request