Load Transfer Mechanism And Long-term Settlement Of The Existing Expressway Reinforced By XCC Piles Under Traffic Load

The differences between the existing and new expressways are,the deformation of the existing expressway which is developing under the static load of the embankment,the additional load of the asphalt overlay,and the traffic load,and the structure of the existing expressway which is a pavement-embankment-ground composite structure.There are few reports about the research on the existing expressway under the traffic load,especially the coupling of the static and dynamic load.This thesis focuses on the existing expressway under the traffic load.It begins with a summary of settlement mechanism,ground improvement technique,and the traffic load in the expressway.Subsequently a simplified analytical model for piled embankment subjected to a moving load was proposed,in which the non-linear behavior of the embankment material is considered.Hereafter the focus is on the dynamic characteristics of the existing expressway under the traffic load,and the influence of the construction above the surface and the soil around piles below the surface is respectively examined.Besides the calculated method for the long-term settlement of XCC piles reinforced composite ground under the traffic load was proposed.After theoretical analyses,large-scale model tests and numerical simulations,results for the construction above and below the surface are presented.It is shown that the efficiency E_m decreases obviously with increasing the velocity ratio c/c₂ at c/c₂>0.43.The cumulative deformation of a geogrid increases rapidly with the increasing of the static and dynamic loads as the value of the ratio of dynamic strain is over 0.048.The embankment and XCC piles have important roles in the transfer of vibration energy.The asymmetric effect of the dynamic response within 2R_?for the XCC pile is found.