Study On The Formation Mechanism Of Soil Arching Effect Of Floating Pile-supported Embankment Under Static And Dynamic Loads

Pile-supported reinforced embankments are widely used in engineering as a soft soil foundation treatment technology.Thick soft foundations are widely distributed in the eastern coastal areas of China.In actual design and construction,the pile body fails to penetrate the soft soil into the hard soil layer or bedrock,making it a floating pile.At present,floating pilesupported reinforced embankments have been used in actual projects,and based on engineering experience,there are certain requirements for the bearing capacity of the soil at the bottom of the pile during design and construction.The design theory of the floating pilesupported reinforced embankment lags behind the actual engineering application,and there is little research on the mechanical characteristics of the floating pile pile-supported reinforced embankment.Numerical simulation and theoretical derivation are combined to study the formation of flexible and rigid floating pile-supported reinforced embankments under static loads,the formation of soil arches,the effect of reinforced membrane effect,and the interaction of piles and soils.The development pattern of soil arching effect in rigid suspended pile pile-supported reinforced embankment under dynamic load is also studied.The main research progress made in this paper is as follows:(1)Based on the engineering data parameters in the paper,the numerical simulation software ABAQUS was used to establish three-dimensional numerical models of flexible floating piles,rigid floating piles and end-bearing piles(including pile caps)pile-supported embankments.The model was compared and verified based on the post-processing results.(2)The influence of pile spacing and embankment height on the soil arching effect and pile-soil effect of flexible pile-supported embankment is studied from multiple angles of stress field,displacement field,pile axial force and lateral friction resistance by numerical analysis method.The influence of the bearing capacity of the bearing layer,the pile spacing,the height of the embankment,the friction and the cohesion of the fill on the soil arching effect,the tensile membrane effect and the pile-soil interaction of the rigid floating pilesupported embankment are studied by numerical analysis.According to the numerical calculation results,the conditions for forming a complete soil arch when the pile tip is located in the soft soil layer and the harder soil layer are proposed.(3)The influence of dynamic load on the soil arching effect of rigid floating pilesupported embankment is studied through numerical analysis,and the influence of both on the embankment stress and settlement development pattern by changing the vehicle axle load and running speed are analyzed,as well as the influence on the reinforcement and reinforcement.The influence of pile-soil action.(4)Based on Hewlett and Randolph soil arching theory and methods,according to the obtained stress distribution diagram,the inner and outer arch heights are corrected for the two situations where the pile bottom of rigid pile-supported embankment is located in the soft soil layer and the harder soil layer.According to the direction of the maximum principal stress,the Zaeske and Kempfert soil arch theory is chosen,and according to the obtained vertical displacement distribution diagrams,the arch heights of the rigid suspension pile pilesupported embankment are respectively modified in the soft soil layer and the relatively harder soil layer.(5)Considering the settlement of the pile top or the relative settlement of the pile-soil,combining the soil arching effect,the membrane effect,the supporting effect of the foundation,the consolidation effect of the foundation soil and the pile-soil interaction,the soil stress between the piles at the bottom of the embankment is finally solved by two methods.