| The paper takes XiDa segment of Guangxi coastal highway as the engineering background.Because of its special geological formation and soft soil widely existed in roadbed.This section designs the method of low embankment.There are some features:Firstly,high level,it is 30cm below the ground to the normal water level and hard to be drained;Secondly,except for the saturated soft clay,it include the saturated sand;Thirdly,due to the effect of artificial seawater farmed,seawater,groundwater has crystal type and crystal decomposition corrosion on concrete.which has greatly restricted the road of the long-term stability and safety usage.And it leads to difficult construction of coastal road.Generally the height of low embankment fill within 2.5m.Adopting scheme of low embankment,load transferring to the soil will increase stress and produce uneven settlement and low residual deformation of embankment foundation.This paper aims to change embankment structure to improve ground stress and make it uniform distribution by gravel.The author divided the asphalt pavement and cement concrete pavement consider as two cases.Firstly,according to the traffic load required by specifications,which the theory of multilayer elastic system of asphalt pavement to and the half-elastic-space foundation theory of finite rectangular plate of cement concrete pavement,author analyze stress situation that traffic load transfer to the top of the pavement layer.Then the complex stress distribution simplified into a rectangular load via linear fitting;Secondly,owing to the equal area criterion,the low embankment horizontal stiffness method includes variable stiffness method,the vertical variable stiffness method and vertical horizontal variable stiffness method,a total of 9 groups of 31 schemes;Thirdly,related models are established and calculated by the finite element software of ABAQUS.Finally,the author sorted data and analyze embankment subgrade stress diffusion properties,stress distribution and surface sedimentation characteristics.The results show that:1.The stress distribution and the embankment subgrade stress is no obvious relationship.2.The best scheme of asphalt pavement from the vertical horizontal coupling variable stiffness method,28-3 scheme uses 4*1.7m anti-trapezoidal gravel wall+embankment top and bottom two gravel layer,gravel layer due to drainage,construction for the coastal embankment;scheme of 17-1 with arch angle 78.7°+4*1.5m+6*1.0m layout,whose average stress is the smallest.But in the construction process drainage is difficult.It is only applicable to the general embankment of low level;3.The best scheme of cement concrete pavement is also from the vertical horizontal coupling variable stiffness method.Where plan 27-2 and 28-2 is respectively by T type wall and inverted trapezoidal walls and bottom of embankment gravel layer.And both can reach the average minimum stress,but from the difficulty of construction process of T type wall is more simple,and the bottom gravel layer also plays a role of drainage,suitable for the coastal embankment;4.Compared with compaction of embankment,each scheme of Low embankment in asphalt pavement can reduce the instantaneous settlement,and individual scheme can improve pavement uneven settlement.Similarly,the each scheme of cement concrete pavement can also reduce settlement of pavement. |
