Stability Analysis Of Widened Reinforced Embankment On Soft Ground

Soft soil is widely distributed in our country.With the rapid development of transportation,the widening and reconstruction of embankment on soft soil has been vigorously carried out.As a kind of geosynthetic material,geogrid can effectively reduce the differential settlement between the new and old roadbed and improve the stability of the embankment.It has been successfully applied to such projects.However,China’s current highway subgrade design specifications do not clarify the stability analysis method of widened reinforced embankment on soft ground,and there is still great arbitrariness at the design and analysis and other aspects.This paper focuses on the analysis of the stability of the widened reinforced embankment on soft ground,and the main work is as follows:(1)Through literature research,the stability check calculation of embankment on soft ground,roadbed widening and reconstruction,and reinforced embankment in the current technical specifications of our country’s highway industry were summarized.Some aspects,including the stability check calculation method,load,strength parameters index,and the allowable stability safety factor value,etc.have been compared parallelly,and the disadvantages of these technical specifications in the stability analysis of widened reinforced embankment on soft ground have been pointed out.The limit equilibrium method is used in the analysis of the stability in the current available specifications,but the stability analysis method of the widened reinforced embankment on soft ground has not been clearly proposed.(2)Two programs for soil slope stability analysis based on limit equilibrium method,SLIDE and LEAME,were selected to carry out parallelly comparison from the basic principle and analysis algorithm of reinforced soil slope stability analysis,including the calculation of safety factor and core input parameters of reinforcement,and related discussion was performed with a specific case example.The SLIDE software is more industrial and more comprehensive in consideration,and a wider application range than the LEAME software.(3)The challenges faced in the stability analysis of widened reinforced roads on soft ground were illustrated.A numerical model of single-sided widening and reinforced embankments on soft ground was constructed after introducing some key techniques of finite element strength reduction analysis based on PLAXIS software.The distribution laws of stability safety factor,sliding surface shape,geogrid axial force,foundation settlement and lateral displacement of soft ground were analyzed.(4)The sensitivity analysis of the influence of geogrid tensile stiffness,layout position,reinforcement-soil interface behavior on the stability of widened reinforced embankment on soft ground was carried out.Based on the analysis of 3 factors and 5 levels orthogonal design,the influence of the three factors on the stability safety factor weights queue in the order was made clear as follows: the geogrid layout position > reinforcement-soil interface behavior > geogrid tensile stiffness.The research results can provide scientific guidance for the improvement of the stability analysis technology of widened reinforced embankment on soft ground,and enrich the design technology of highway roadbed widening and reconstruction.