Structural Mechanics Analysis Of Flexible Base Asphalt Pavement Under Heavy Load Conditions

With the rapid development of the national economy,the road transport shows "Heavy load,large flow and channelized traffic" features.The traffic flow on the road has been increasing rapidly,and the number of heavy load and overloaded vehicles has risen sharply.The effects of heavy load and overloaded vehicles are the most serious.Domestic form is given priority to with semi-rigid base asphalt pavement surface play an important role in the use,but at the same time also produced many problems,many roads are in serious condition of early destruction in the early use of structural damage,affect driving safety.In comparison,the flexible base asphalt pavement is superior to semi-rigid asphalt pavement because of its material properties.As a form of pavement structure which has only begun to be paid attention to in recent years,the development of the flexible base asphalt pavement is still in its initial stage in China,and further investigation is needed.In this paper,based on the current road serious overload overload phenomenon and domestic common semi-rigid base asphalt pavement early damage phenomenon leads to the research and analysis of flexible base asphalt pavement structure.Based on the multi-layer elastic laminar theory,the finite element software ABAQUS is used to establish an analytical model.By drawing from the domestic and foreign advanced concept and design method of asphalt pavement structure design,and combining the common damage in the form of flexible base asphalt pavement,the flexible base asphalt pavement on the optimization of design index,the optimized design index table for road deflection,surface layer upon layer of bottom shear stress,surface layer upon layer bottom tensile stress and tensile strain,the top soil base compressive strain and asphalt mixture layer compressive stress.Index using the optimized design of flexible base asphalt pavement structural mechanics analysis and research on pavement performance,the results show that by adding asphalt road surface and asphalt stabilized macadam base modulus of elasticity,such as big thickness of the material can effectively reduce the road of the deflection and the top soil base compressive strain,improve road capacity,reduce the possibility of rut occurred.Increasing the thickness of asphalt stabilized macadam base can reduce the surface layers of the bottom shear stress,reduce the risk of shear failure on the surface,but at the same time increase the surface layers of bottom bending tensile stress and tensile strain,causes fatigue damage occurrence probability to rise.In the design of flexible base asphalt pavement structure,should use thicker asphalt layer,so that shear stress in the surface layers of bottom can avoid the structure layer,the position of the bending tensile stress and tensile strain is larger,the effective avoid pavement shear failure and fatigue failure.Increasing the base and soil modulus can improve the load-carrying capacity of the road and reduce the damage to the road surface.However,it is not obvious that the performance of the road surface is improved when the modulus is too large,and the appropriate principle should be grasped from the Angle of benefit and feasibility of implementation.