Study On The Long-Term Settlement And Disease Mechanism Of Subgrade

As an important part of the road structure,embankment not only bearing the weight of itself,but also supporting and delivering the passing traffic loads.Under the influences of the long-term car traffic load,water,wind,rain,snow,cold,high temperature,etc.,and a variety of adverse geological conditions and human factors,subgrade come into mud pumping,differential settlement and other diseases.Roadbed construction combined with a variety of structures,such as retaining walls.While roadbed is being filled and used,structures will be subjected to earth pressure due to external loads,and then have an impact on the deformation and stability of structures.For these considerations,this paper carried a more comprehensive study on the common technical problems during roadbed construction and opening to traffic.The main contents are as follows:(1)Burying earth pressure cells and inclinometer by site to measure forces and displacements of retaining wall during the subgrade construction.And then finite element method was used to simulate the distribution of earth pressure and calculate retaining wall displacement.(2)Long-term subgrade settlement was observed by burying settlement-boards,the measured data was used through Asaoka and empirical methods to predict subsequent settlement,and the prediction was of high reliability.(3)Dynamic soil-water coupling equations of saturated-unsaturated soils were established combined with the existing achievements,the fractal model was used to determine the unsaturated soil water characteristic curve and relative permeability,and then by the means of COMSOL to calculate and analyze the influences of vehicle weight,traffic,groundwater level as well as embankment height to pore water pressure under long-term traffic loads.(4)Combining finite element method and empirical formula to calculate subgrade total settlement from the beginning of construction to certain time of opening to traffic.The long-term subgrade consolidation settlement and the parameters of empirical formula can get from finite element method calculated results,empirical formula was used to calculate the cumulative plastic deformation of subgrade.