The Investigation On Dynamic Property Of Embankment Reinforced With Geocell By Laboratory Test And Finite Element Analysis

As a form of three-dimensional reinforcement,geocell has been widely used in many fields both at home and abroad,through the lateral restraining action of the lateral wall,the action of friction with the upper and the lower interface of the reinforcement layer,the action of stress diffusion of reinforced layer and flexible raft foundation,geocell can improve the whole stability of embankment and reduce the deformation of embankment.But at present,the research of reinforced embankment with geocell is more concentrated in the static loading condition,and the research on dynamic load is less.In this paper,the dynamic performance of embankment under dynamic load is studied as follows:Through dynamic triaxial tests,dynamic elastic modulus,damping ratio and dynamic modulus of resilience of saturated sand reinforced with geocell under different confining pressure and cyclic stress amplitude,different reinforcement layers and height of the geocell are studied.The experimental results show that the more of the reinforced layers and the higher of the geocell,the better the limitation on the dynamic strain.With dynamic strain increases,dynamic elastic modulus of saturated sand are gradually reduced under various operating conditions,with the confining pressure increases,the dynamic elastic modulus increase and the damping ratio decrease under the same strain level.Under the same strain level,the dynamic modulus of resilience increases with the increase of the layers and decrease with the dynamic stress increases,the early stage of the dynamic stress influence on the dynamic modulus of resilience is more significant.Through geocell reinforced embankment model test,the ultimate bearing capacity,the deformation and internal earth pressure under long-term cyclic loading,the change of the ultimate bearing capacity after fixed time cyclic loading of the reinforced embankment,the vertical cumulative deformation and the lateral cumulative deformation under stepped cyclic loading are researched under various operating conditions,and contrast the embankment under stepped cyclic loading with the embankment under fixed amplitude cyclic loading and static loading,the difference of mechanical properties of different loading schemes are studied.The experimental results show that geocell can significantly increase the ultimate bearing capacity of foundation and observably reduce the vertical cumulative deformation and the lateral cumulative deformation,this inhibition effect is more significant with the increase of the reinforcement layers and the geocell height.the weld space of geocell can also affect the ultimate bearing capacity of the embankment under static loading in a certain degree,and has little effect on the lateral cumulative deformation of the slope.The reinforcement layers has little effect on the vertical cumulative deformation of the embankment,and the vertical cumulative deformation and lateral cumulative cumulative deformation of the slope can be reduced in different degrees with the increase of the height and the decrease of the welding space.For unreinforced embankment,the change of dynamic load amplitude and vibration times lead to different degrees of reduction of the ultimate bearing capacity after vibration,For the reinforced embankment,when the dynamic load amplitude is greater than or equal to 30 kPa or the number of dynamic load vibration is greater than or equal to 1000,the ultimate bearing capacity after vibration have different degrees of improvement.Geocell can significantly increase the capacity of the embankment to withstand the stepped cyclic loading and reduce the lateral cumulative settlement,the reinforcement effect of two or more layers is more obvious than single layer,the change of the welding space and the geocell height can affect the bearing capacity of the embankment under stepped cyclic loading,the capacity of the embankment to withstand the graded cyclic loading increase with the increase of the height and the decrease of the welding space.Geocell reinforced embankment can reduce the vertical cumulative deformation of the embankment under stepped cyclic loading and fixed amplitude cyclic loading,when the number of vibration is greater than or equal to 9000,the inhibitory effect of vertical cumulative deformation of the embankment can be revealed under stepped cyclic loading,when the number of vibration is greater than or equal to 8000,the vertical cumulative settlement of embankment under stepped cyclic loading exceeds the fixed amplitude cyclic loading,when the number of vibration is the same,the lateral cumulative settlement of embankment under fixed amplitude cyclic loading exceeds the stepped cyclic loading.Through ABAQUS finite element software for three-dimensional modeling of reinforced embankment,research on the variation regularity of strain field and displacement field by changing the reinforced layers,the geocell height,the geocell welding space,and contrast with the physical model test.The experimental results show that the variation regularity of vertical cumulative deformation with the numerical model embankment is basically consistent with the physical model,but the numerical simulation results are larger than the experimental value.The vertical cumulative deformation and lateral cumulative deformation nephogram of the embankment under the static loading are obviously influenced by the reinforcement effect,in particular,the lateral deformation in the inner region of embankment is greatly influenced by reinforcement.The vertical and lateral cumulative deformation of the central axial line of the loading plate are greatly influenced by reinforcement,reinforcement layers can be to some extent to ease the vertical cumulative concentrated deformation.The lateral restraining action of geocell can significantly reduce the lateral earth pressure in the different position of the embankment,lateral earth pressure is roughly same in the vertical distribution,the horizontal change is more obvious.The trend of vertical cumulative settlement of embankment with the change of vibration times under dynamic load is in agreement with the experimental results,the vertical cumulative deformation and the lateral cumulative deformation of the slope are increased with the the increase of vibration time,the effect of the reinforcement layers and the height of geocell on the lateral deformation of the slope is better than that of the weld space of geocell.With the increase of vibration time,the lateral earth pressure of the embankment under each reinforcement condition increases in all positions.Geocell reinforced can play a role of stress dispersion and flexibility raft foundation under static loading and dynamic load.