Comparative Analysis Of Reinforced Earth Retaining Wall Under Different Standards And Compaction Stress Effect

In engineering practice,the research on the working performance of reinforced retaining walls is a very important and realistic topic,which involves the strength(reinforcement mechanism),stability(internal / external),and deformation of reinforcement.(Mainly refers to the horizontal deformation of the panel,the settlement displacement of the top of the wall,etc.),material strength,wall properties,and evaluation of the reinforcement effect have not been completely resolved.The finite element numerical analysis method is a powerful calculation method for simulating the working mechanism of a reinforced retaining wall.It can make up for the shortcomings of the limit equilibrium method,and is more consistent with actual engineering in terms of stress,strain and deformation.The development of analytical methods has promoted the research and application of reinforced retaining walls.This paper mainly studies three aspects of the comparative analysis of the three countries' norms through the finite element numerical analysis method,the numerical simulation analysis of the compaction stress of the reinforced earth retaining wall and the effect of different compaction methods on the back of the panel on the reinforced earth retaining wall.The main contents are:(1)Comparing and analyzing the design calculations of reinforced earth retaining walls by applying the technical specifications of geosynthetics in China,Design and Construction of Mechanically Stabilized Earth Walls and Reinforced Soil Slopes in the United States,and Code of practice for strengthened/reinforced soils and other fills in the United Kingdom.The differences among the three countries' specifications are studied with respect to the earth pressure calculation,anti-pullout stability of reinforcement,and horizontal anti-sliding stability.Based on the reinforcement length and spacing calculated with different specifications,the lateral displacement of the wall facing,the tensile load of the reinforcement,the sliding surface,and the safety factor are compared.By comparing the formulas,it can be seen that the British standard provides a reasonable load partial coefficient and safety factor for structure design,which is more in line with the actual working conditions.From the numerical results,it can be seen that the US standard shows a good reinforcement effect.However,the design of US is too conservative,thus is not economic in practice.The Chinese standard has a wide applicability but the accuracy is not high.(2)Based on the literature numerical modeling type II(2D),a three-dimensional dynamic compaction model considering different load widths is proposed and verified.At the same time,a calculation formula of compaction stress retaining wall considering Chinese norms was introduced,and the three-dimensional dynamic load moving mode was discussed.Firstly,according to the selection of the equivalent loading method,the influence of different load widths on the retaining wall is discussed according to the strain of the reinforcement,the lateral deformation of the panel,the earth pressure of theback soil and the compressive stress of the base,and then verify the calculation formula by the influence of the compaction stress on the depth.The analysis shows that the calculation method of the equivalent load movement method is closer to the measured value than the second and third methods;the strain change trend of each layer is basically the same,showing two “peaks”,the first one is located at the back of the panel,the second place Peak load point due to shear strain concentration(potential fracture surface);the type of compaction modeling does not affect the distribution of vertical compressive stress at the bottom of the wall;only when the additional load of the retaining wall exceeds the compaction load,the compaction stress the effect will dissipate.At the same time,for different compaction stresses,ribs and soil properties,the corresponding compaction depth is also different;The strip load width(B)has obvious impaction on the internal stress prediction of the retaining wall.(3)Based on the literature's numerical modeling type II(2D),the influence of the compaction method of the back of the block panel on the performance of the geosynthetics-reinforced retaining wall was studied by a finite element numerical calculation analysis method.Firstly,the rationality of the numerical model in terms of boundary condition setting,grid division,soil model and material parameters is verified according to wall toe load,horizontal deformation of panel and earth pressure on the back.Secondly,the effects of different compaction methods on the back of the panel on the retaining wall were discussed by studying the total displacement analysis,the tensile load analysis of the tendons,the displacement analysis of the wall top settlement,and the depth of compaction stress.The numerical analysis results show some empirical rules about the use of light compaction near the panel.The subsequent performance of each compaction model in bearing capacity should be studied by applying external loads on the top of the wall.