| Nowadays,reinforced soil structure has been widely used in geotechnical engineering because of its excellent performance.With the strategic development of the Loess Plateau in the central and western regions,the construction of these regions has been developed unprecedentedly.However,due to the complex geological environment in the region,it is very common to meet the deep-incised terrain and high fill for some large industrial sites in the construction process and it is necessary to construct high fill slope in order to get the flat ground.Compared with the traditional design and construction methods of large area excavation and backfill,the stepped reinforced earth retaining wall becomes a more effective structural form under special terrain conditions,but there is no clear design method for this kind of project,and the specification is only confined to the vertical reinforced earth retaining wall,and the influence of the elevation angle of the face panel on the structure is not involved.With the increase of retaining wall height,the vertical reinforced earth retaining wall structure can't meet the design requirements,and the influence of the elevation angle of the face panel on the structure can't be ignored.In order to improve the existing design theory of stepped reinforced earth retaining wall and meet the stability requirements of reinforced earth retaining wall,the finite element two-dimensional model of reinforced earth retaining wall is established based on the practical engineering through the numerical simulation software ANSYS,and the structural characteristics and deformation of reinforced earth retaining wall with different elevation angles are analyzed and studied.The works in this paper are as follows:(1)The development process of reinforced soil technology is introduced,and the present situation of the research on reinforced earth retaining wall and finite element method in recent years,and the reinforcement mechanism and failure mode of reinforced soil structure are summarized.(2)According to the structure characteristics of reinforced earth retaining wall,the filler,face panel and a suitable constitutive model of reinforcement and its element types are selected and the finite element model of reinforced earth retaining wall is established by introducing the Interface reflection units of the reinforcement-soil and soil-panel.(3)The numerical simulation results are analyzed in terms of horizontal and vertical displacement of face panel of reinforced earth retaining wall,the settlement situation of top and bottom of the wall,the vertical stress of the base and the pulling force of the grid and so on.The research shows that there is a sudden change in the deformation of retaining wall when the elevation of panel is 75.9°,and the deformation transform from a convex curve to a linear distribution gradually,and the phenomenon of "bugling wall" tends to disappear as the elevation angle of reinforced earth retaining wall is reduced from 90°to 53.1°.Compared with the horizontal and vertical displacement cloud charts of reinforced earth retaining wall,the horizontal displacement distribution of the retaining wall are greatly changed,but the vertical displacement is not when the elevation angle of reinforced earth retaining wall changes,which conclude that the horizontal displacement of reinforced earth retaining wall can be suppressed by reinforcement,but the vertical displacement can be not.There is no obvious differential settlement between the backfill and the panel at the top and bottom of the wall,which can avoid the damage caused by the differential settlement of reinforced earth retaining wall in the 4 conditions compared with the calculation results,that demonstrate the structure design of stepped reinforced earth retaining wall is reasonable,and the calculation results can be used as reference in practical engineering.What's more,the reinforcement can reduce the vertical ground stress of reinforced earth retaining wall in the structure of reinforced earth retaining wall effectively,and the stress concentration at the toe of the wall is obviously weakened,and the overall compression of the base is improved with the decrease of the elevation of the panel.Moreover,The potential sliding surface of the reinforced soil retaining wall is similar to the logarithmic spiral curve,the fracture surface calculated by the finite element method moves to the inside of the stiffener integrally compared with simplified potential failure surface obtained according to the limit equilibrium theory.(4)The stepped reinforced earth retaining wall will be optimized from selection of backfill,arrangement of reinforcement and setting of platform width according to reduce the horizontal displacement of the wall based on the practical engineering.It is shows that the desirable cohesion is greater than 20 kPa,the internal friction angle is greater than 25 degrees of backfill is more appropriate in the engineering generally;and the reinforcement spacing should be 0.4m-0.5m,and the length of the reinforcement should be 0.5-0.7 times the wall height,and the width of stepped steps should be designed as 3m-4m according to the study results,which can not only prevents the a sliding through face of retaining wall from forming,but also enhance the stability of stepped reinforced earth retaining wall. |
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