Research On Performance And Failure Modes Of Reinforced Retaining Wall Under Cyclic Dynamic Loading

The design methods of the reinforced earth retaining wall currently in use in our country are based on the analysis of the overall stress,the anti-pull mechanism of the reinforcement and the analysis of the fracture of the reinforcement,seldom relates to the settlement of the foundation and the displacement analysis of the panel under working conditions.Based on the self-designed 1500mm×1000mm×1300mm(length×width×height)retaining wall model test box,the paper studies the load-bearing performance of strip-based reinforced earth retaining wall under different loads,and analyzes the reinforced earth based on the results.The following conclusions have been drawn from the related problems of additional stress transfer of the earth wall,foundation settlement,horizontal displacement of the panel,failure modes of the retaining wall,and factors affecting the acceleration response of the soil.(1)In the reinforced earth retaining wall structure,adding the reinforced concrete to the soil can effectively increase the ultimate bearing capacity of the retaining wall.The increase of the number of layers of reinforcement can effectively reduce the settlement of the loaded plate.Settling under static load conditions,a linear increase trend.Changing the length of the geogrid inside the reinforced earth retaining wall and the number of transverse ribs all reduce the ultimate bearing capacity of the retaining wall structure.The smaller the length of the geogrid,the greater the subsidence of the loading plate;the less the number of geogrid transverse ribs The larger the loading plate settles.(2)Under the static load conditions,the failure modes are changed under different working conditions such as changing the number of layers,length,and number of vertical and horizontal ribs,while under dynamic load conditions,they are mostly local shear failures.(3)The geogrid has an obstructive effect on the additional stress transmitted from the upper soil and plays a significant role in the attenuation of the additional stress.It reduces the length of the geogrid and the number of transverse ribs and changes the internal stress of the soil.In the field,the vertical additional stress is transmitted to the deeper soil,affecting the bearing performance of the retaining wall.(4)In the case of dynamic load conditions,minus the settlement of the base of the increase of the geogrid transverse rib,the frequency geogrid minus the vertical and horizontal ribs greatly reduces the ultimate bearing capacity of the structure and increases the The settlement of the strip-shaped base loading plate increases the unpredictability of the damage.When the horizontal displacement of the retaining wall panel is loaded in stages,the height of the retaining wall presents a phenomenon of large and small.In the amplitude condition,when the load form is converted into dynamic load,the horizontal displacement of the panel has mutations of different amplitudes and abrupt changes.The amplitude increases with the decrease of the number of geogrid ribs;in frequency conditions,increasing the loading frequency at each stage of the load during the early period of dynamic load has no significant effect on the horizontal displacement of the panel,when loading to the later stage.At this time,the loading frequency has a significant effect on the horizontal displacement of the panel.The amplitude condition has a greater influence on the horizontal displacement of the retaining wall panel than the frequency condition.(5)In the amplitude condition,the additional stress from the observation point of the first layer of the vibration source shows a smaller and smaller attenuation than the original peak stress of the loading plate.In frequency operating conditions,the additional stress at the observation point of the C1 layer geogrid shows a smaller and smaller attenuation than the original peak stress at the loading plate.At the same level,there is a vertical additional stress inside the soil body,which is the largest value directly below the loading plate,and the loading plate is not large at both sides.In the amplitude condition,the vertical and horizontal ribs of the geogrid are reduced,and the amplitude of attenuation is reduced.Under the frequency conditions,the vertical and horizontal ribs of the geogrid are reduced and the amplitude of attenuation increases.(6)In the working condition of the amplitude,the more gratings are the transverse ribs,the larger the strain of the grille is.Under frequency conditions,the C1 layer geogrid near the vibration source is abruptly changed at the ultimate load bearing load level,while other layers have no major changes.The strain of the geogrid in the soil is related to the depth of the additional stress.The greater the influence depth of the additional stress,the greater the strain of the geogrid.The amplitude of the vertical additional stress in the amplitude condition is greater than the frequency condition.(7)The response of acceleration in soil is related to factors such as loading frequency,geogrid form,loading amplitude and central value,and these factors influence each other and comprehensively affect the response of acceleration.