Research On Dynamic Response Analysis Of Low Embankment Of Yangtze River In Nanjing Under Traffic Load

With the further promotion of the investment in transportation infrastructure,the demand for the construction of high-grade roads also expands.Nanjing city intersected by the Yangtze river,has a unique Yangtze river floodplain topography.Due to the weakness of the Yangtze river flood plains layer and water content,part of soft soil layer located in the depth of traffic load is easy to produce uneven settlement in the process of road operation,so the dynamic response characteristics of the soil under traffic load and control methods of the research is particularly important.Based on the construction project of Hengjiang Avenue in Jiangbei New District of Nanjing,the Yangtze river flood plains layer by adopting the combination of field test and finite element simulation method,the traffic load in the Yangtze river floodplain low embankment in the dynamic response conditions is studied,and the related factors influencing the traffic load dynamic response is discussed,so as to provide beneficial reference for the similar projects.The main work and achievements are as follows:(1)Based on the field static penetration test data and standard penetration test data,the basic properties of the overplain soil layer in Nanjing Yangtze River is studied.At the same time,the compression characteristics of the existing soft soil in Nanjing Yangtze River floodplain phase are summarized,and the influence of the soil structure on embankment filling is discussed and analyzed.(2)Relying on the construction project of Nanjing Hengjiang Road construction project,dynamic response of traffic load field experiment is carried out.Based on the field text data,the characteristics of the dynamic stress response of the traffic load in the embankment with the change of time are analyzed emphatically,the vertical and transverse distribution of the dynamic stress is pointed out by combining with the theoretical analysis,and the influence of the speed and the road surface property on the dynamic stress distribution is studied.The Boussinesq solution was compared with the field measured value,and the reasons for the difference between the measured value and the numerical solution are analyzed.(3)Considering the constitutive law of soil,simplified model of traffic load and boundary conditions,a three-dimensional model of vehicle-embankment-subgrade under traffic load is established by PLAXIS 3D.The dynamic process of single loading of traffic load is simulated by finite element method,and the dynamic indexes such as vertical additional dynamic stress,vertical acceleration and vertical displacement are analyzed.By changing the corresponding parameters in the model,the influence of overloading on the dynamic response of the road during daily operation is analyzed.(4)By changing the parameters of the finite element model,the factors influencing the dynamic response of the traffic load are analyzed by finite element numerical method.By changing the stiffness of the pavement surface layer,the stiffness of the base layer,the roughness of the pavement,the height of the embankment,the parameters of the soft and hard shell layer and the properties of the soft soil,the change characteristics of the corresponding dynamic response under different working conditions are compared.The control measures of dynamic response of traffic load are summarized to provide useful reference for similar projects.