The Study On The Mechanical Characteristics Of Tire-geogrid Reinforced Retaining Wall By Vehicle Loading

With the deepening development of economy,the improvement of domestic highway construction and the logistics industry,the transport vehicles also increase year by year.Recently,the overlength and overloaded vehicles appear in regions,which brings the pavement severe harm.Hence,the dynamic response and instability mechanism of reinforced earth retaining structure under the traffic loads are highly valued.Meanwhile,as the increasing number of vehicles,more problems about how to disposal the waste tire will be faced.Waste tires have the advantages of high tensile strength,good toughness,anti-wear,aging-resistance and anti-collision.Reinforcing waste tires make the construction easy and low-cost while adapting to the deformation and keeping long-term stability.Recent decades,a growing number of waste tires regarded as reinforced materials,is applied to reinforced retaining wall.In this article,a composite reinforcement combined by waste tires and biaxial geo-grid will be applied in the reinforced retaining wall.Through the model tests,a deepen research of the mechanical characteristics of tire-geogrid reinforced retaining wall will be conducted.In this paper,a simulation experiment of vehicle load has been conducted through the independently-developed machine.An model test of tire-geogrid reinforced retaining wall has been conducted as well.The tests give a comparative analysis the reinforced performance between biaxial geo-grid,tire,geo-cell and tire-geogrid reinforcement materials.Under the circumstance of the same vehicle speed and diverse vehicle loads,the acceleration of different reinforced retaining walls,the dynamic earth pressure and the wall deformation will be researched,so as the mechanical characteristics and deformation regulation.The tests demonstrate that compare to the biaxial geogrid,tire and geocell,the tire-geogrid reinforcement materials have advantages of enhancing seismic performance and stability of reinforced retaining wall and reducing the wall deformation.Additionally,in the project of tire-geogrid reinforcement materials,the effectiveness is better while the space between tires equals to the size of radius of tire,which could save 30% of material costs.Therefore,based on the optimal combination of tire-geogrid,the the dynamic response characteristics of reinforced retaining wall has been studied with different speed.Under the vehicle load,the degree of wall deformation and the acceleration of tire-geogrid reinforced retaining wall will increase along with the relative height of the wall.The biggest deformation rate is at y/H=0.7 and the acceleration peak is at the top of the wall.Moreover,the dynamic earth pressure will change according to the vehicle load.After reaching its peak value,the increasing rate becomes slowly and stably.With function fitting.,the acceleration amplification coefficient increases with relative height of the wall in the form of exponential function and also raise with the relative load in the form of logarithmic function.Ultimately,the accumulative settlement and earth pressure of tire-geogridreinforced retaining wall have been analyzed through static and dynamic load test.Under the same size of static load and dynamic load test,the accumulative settlement which is applied two times cyclic loading would exceed that of static load test and the earth pressure peak which is applied four times cyclic loading could exceed that of static load test.The stable earth pressure under the vehicle load with 60km/h could beyond the pressure peak of equivalent static load of 20%.Therefore,the accumulative settlement and earth pressure of tire-geogrid reinforced retaining wall have an common influence with number of cyclic loading and the loading time.