The Study On Characteristics Of Small Spacing Reinforced Retaining Wall

The traditional reinforced earth retaining wall MSE has been widely used in the field of civil engineering,but the traditional reinforced earth retaining wall due to the larger spacing,there is a large lateral displacement of the structure,the overall deformation is not coordinated,Stress concentration and other issues.(Geosynthetics Reinforced Soil,GRS)is a new type of reinforced soil with a reinforced spacing of less than 0.3m.The preliminary study shows that the structure has the advantages of small settling capacity,good overall stability and good seismic performance.In order to explore the difference between the small spacing reinforced earth retaining wall and the traditional reinforced earth retaining wall,we can understand the reinforcement mechanism of the small spacing reinforced earth retaining wall and obtain the deformation law of the small spacing reinforced earth retaining wall.In this paper,the reinforcement mechanism and its structural characteristics are studied to promote the application of small spacing reinforced earth retaining wall in the field of highway engineering in China.The main research work and conclusions are as follows:1?The research progress of soil arching effect of reinforced soil structure and the research progress of GRS retaining wall are reviewed in literature.2?The results show that:(1)the particle size range is 4-12 mm,the maximum and minimum particle size ratio is 3,the soil sample model is almost no Suspended particles,sample soil grade is better.(2)In the simulated biaxial test,if the friction coefficient of the particles is too large,the particles are prone to overlap,resulting in distortion of the simulated soil,the proposed friction coefficient as much as possible to control the following 1.0.(3)particle friction coefficient of 0.7,the simulation of soil shear strength index is the most reasonable.3?The influence of the reinforcement spacing,the porosity of the filler and the friction coefficient of the interface between the reinforcement and the soil on the soil arching effect of the reinforced soil are analyzed by using the PFC software to establish the numerical model of the reinforced soil structure.The results show that:(1)When the reinforcement spacing is too large,the soil arch can not be formed.When the reinforcement spacing is too small,the soil at the panel is constrained by the tendons,and the soil deformation is uniform and the soil arch is not obvious.0.4m when the soil arch formation,but the reinforcement spacing of 0.2m when the most obvious effect of soil arching.(2)The size of the earth pressure in the reinforced concrete retaining wall panel increases with the increase of the spacing of the reinforcement,and it is generally linear.When the spacing is reinforced,the reinforced earth retaining wall is almost no force.(3)The porosity of soil particles is 0.1,and the effect of friction soil arch is the most obvious.(4)When the friction coefficient is 0.8,the contact force between the particles is the largest,and the soil arching effect is the most obvious.When the friction coefficient is 0.3,the contact force between the particles is very small,and there is almost no soil arching phenomenon.(5)As the reinforced concrete structure panel moves toward the temporary surface,the soil particles also displace,and increase with the increase of the displacement of the panel.4?The GRS and MSE models were established by FLAC software respectively.The tensile stress and the vertical and lateral displacements of the ribs were analyzed.The plasticity of the two kinds of retaining walls was analyzed by the strength reduction method.The results show that:(1)The tensile stress distribution of the two tendons is similar,and the tensile stress of the reinforced concrete wall increases with the increase of the wall height And reduced.(2)The maximum settlement of the GRS retaining wall and the MSE retaining wall is located in the area close to the wall panel,and the settlement of the construction period is much larger than the settlement of the operation period.(3)The maximum lateral displacement of the GRS retaining wall appears in the middle and lower part of the panel,and the lateral displacement is located in the upper part of the panel.The maximum lateral displacement of the MSE retaining wall appears at the position of the whole wall,and the lateral displacement distribution cloud is approximately triangular The(4)The lateral earth pressure at the upper panel of the two retaining wall models is relatively small.As the depth of the retaining wall increases,the lateral earth pressure at the panel increases gradually.5?The vertical displacement and soil pressure distribution of the wall are analyzed by the centrifugal model test method.The comparison between the GRS retaining wall and the MSE retaining wall model before and after loading is carried out.The two models are analyzed under the ultimate load The overall deformation of the body,the destruction of the situation.The results show that:(1)The difference of the settlement of the two kinds of reinforced earth retaining walls is mainly reflected in the reinforced soil structure,but the settlement of the reinforced soil is not very different.(2)The lateral pressure of the panel increases nonlinearly with the increase of the filling height,and the lateral earth pressure of the MSE retaining wall is approximately twice that of the GRS retaining wall lateral earth pressure.(3)The lateral earth pressure of the two reinforced concrete retaining wall structures and the tendons at the end of the tendons showed a nonlinear change,which was roughly S-curve distribution.