Dynamic Response And Numerical Analysis Of Double-beam Model Of Reinforced Embankment Under The Influence Of Cavity

In areas with poor geological conditions,many road projects are inevitably built on empty foundations,or due to changes in groundwater level,improper treatment of subgrades,improper filling,and other reasons,the occurrence of earth caves under the subgrade also occurs from time to time.During the road operation period,the engineering problems caused by the collapse of the earth tunnel caused by the collapse of the pavement roof on the embankment's own weight,vehicle load,and vibration effects have also become an important issue in road construction and operation.In order to prevent the sudden collapse of the cavity,the current common method is to add geosynthetic materials to the subgrade to strengthen the subgrade.In view of this,this paper focuses on the dynamic response and numerical analysis of the double-beam model of reinforced embankment under the influence of the cavity,the main research content and results Including:(1)Improve the classic Euler-Bernoulli beam model,and use this method to study the reinforced embankment under the collapse of the soil cave.Assuming that the road slab is the upper beam and the reinforced layer is the lower beam,considering the coupling effect of the upper and lower beams,the differential equation of the double beam between the bending moment and the settlement of the upper and lower beams is established respectively,and the double beam system is derived using the perturbation theory Response control differential equations and related solutions to simulate the dynamic response between the upper and lower beams.The experimental research results of foreign scholars are compared with the analytical results of the double beam model to verify the effectiveness of the improved double beam model.Based on the differential equations of the double beam model,the embankment fill height and the stiffness ratio of the upper and lower beams are systematically studied.The influence of factors such as the diameter and speed of the soil cavity on the settlement value of the upper and lower beams.The settlement value of the upper and lower beams increases with the height of the fill,the diameter of the soil hole,and the speed of the vehicle.While keeping the rigidity of the upper beam unchanged,the settlement of the lower beam increases as the rigidity ratio of the upper and lower beams increases.(2)Using the large deformation finite element analysis method and the geogrid creep characteristics,a finite element analysis model of the coupling effect of pavement-embankment-reinforced layer-subgrade is established,and the normalized method is used to reveal the road under different working conditions The influence of traffic load on the ultimate bearing capacity and failure mode of the embankment,the pull-out effect of the reinforced layer,and the influence on the movement tendency of the soil.The research results show that the horizontal reinforcement method can improve the ultimate bearing capacity of subgrade.When a geogrid is laid at the bottom of the embankment,it will improve the ultimate bearing capacity of the embankment to a certain extent.When the tensile strength of the reinforcement increases,the bearing capacity ratio will increase,but there is a critical value for the tensile strength.The greater the embankment fill height,the higher the settlement value of the reinforced layer,and the embankment develops from incomplete soil arch effect to complete soil arch effect.The greater the buried depth of the earth tunnel,the lower the ultimate bearing capacity of the subgrade.(3)Relying on foreign scholar Audrey Huckert's full-scale six-month full-scale test in an open place,a double beam model and a three-dimensional numerical model are established,and the analytical results,numerical simulation results are compared with the experimental results.The calculation results show that the results of the three-dimensional numerical model Compared with the experimental data,the results of the analytical solution are consistent with the experimental results,but the overall settlement value is relatively small,indicating that the improved double-beam model has its own limitations.