Stability Analysis Of Reinforced Sand Retaining Wall Based On Interface Characteristics

With the development of economic construction,reinforced earth retaining wall has been widely used in the engineering construction of highway,railway and water conservancy facilities in mountainous areas,and has achieved good economic benefits.The strength characteristics of the filler,the interaction between the filler and the reinforcement,and the load conditions are the important contents of the design of the reinforced earth retaining wall.The sand(medium coarse sand)has the advantages of high internal friction angle and good water permeability,is an ideal backfill material for reinforced earth retaining wall;The interfacial strength between sand and sand,sand and reinforcement is an important factor influencing the stability of reinforced sand retaining wall,At present,There are many studies on the effects of particle size,shear rate and normal stress on the interface characteristics of sand and reinforced sand,while there is little research on the relative compactness of sand;And in the related research on reinforced sand retaining walls,there are few studies on the influence of interfacial strength,sand density and impact load on the working characteristics of reinforced sand walls.In this paper,the shear properties of sand and reinforced sand interface under different density were analyzed through the large scale direct shear test,And combined with the interface direct shear strength parameters,the effect of the interfacial strength,the relative compactness of the filling and the impact load on the overall stability of the geogrid reinforced sand retaining wall was studied by means of numerical analysis.and the conclusions are as follows:(1)The pseudo-friction coefficient,the internal friction angle and the apparent cohesion of the sand and the reinforced sand was increased with the increase of the relative compactness;the apparent cohesion of reinforced sand's interface was bigger than non-reinforced sand's interface,the internal friction angle is smaller than non-reinforced sand's interface;under the same relative compactness,the interfacial friction coefficient ofsand and reinforced sand decreased with the increase of stress,and the decreasing amplitude decreases gradually and tends to stabilize;(2)The safety coefficient of the reinforced wall is greatly affected by the interfacial coupling cohesion and coupling friction angle,higher interfacial strength is more conducive to dispersion the stress and deformation of the soil;relative compactness' s increase can improve the overall stability of the retaining wall,increases was decreases with the increase of the interfacial coupling cohesion;(3)The stress and deformation of geogrid in the bottom of the wall is minimum,and increases with the height of the wall;As the reinforced sand retaining wall which underlying layer strength is higher,the stress range and stress value of the geogrid are smaller in the lower part of the grille wall,should take "up long down short " ways of arrangement reinforcement;(4)The overall stability of the reinforced sand retaining wall was synergy results of panel's form and strength,interfacial properties of reinforced soil,and other external factors,and not the strength of the panel is higher,the better the overall stability of the retaining wall,in the design of reinfoced wall,should be taken into account the strength of filler,reinforcement and interfacial between reinforcement and soil,selection panel strength rationally;(5)Under the impact load on the top of the wall,the horizontal displacement of the wall increases gradually along the height of the wall,the maximum occurs at the upper part of the retaining wall,Increase the density of the upper part of the wal'sl reinforcement density and reduce the first layer spacing of the reinforcement can effectively limit the horizontal displacement of the top of the wall.