| As an organic combination of reinforced soil retaining wall and anchor pulling retaining wall,the contrasting reinforced soil retaining wall has the advantages of high strength,low deformation,less land occupation and low project cost.At present,there is a lack of systematic and in-depth research on the reinforcement mechanism and design method of contrasting reinforced soil retaining wall.The thesis takes the UAE high-speed heavy-duty double-lane railway project as the engineering background,and investigates the reinforced soil retaining wall scheme with two types of reinforcing materials,namely geobelt and tensile plastic geogrid.The tensile properties of the two reinforced materials and the frictional properties of the reinforced soil interface are experimentally investigated,the contrasting soil retaining wall structural behaviour of the two reinforcing materials is compared and analysed based on finite element numerical simulations,and the design is optimised based on the influence of the technical parameters such as the vertical spacing,the horizontal spacing and the pre-stress of the reinforcing geobelt on the force and deformation of the reinforced soil retaining wall with geobelt.The main findings of the thesis are as follows.（1）Based on the structural characteristics of the contrasting reinforced soil retaining wall,the horizontal soil pressure of the wall panel and the internal and external stability of the structure are calculated with the tensile strength of the lowest reinforcement as the judgment basis for the failure or ultimate state of the retaining wall.（2）In order to determine the mechanical properties of geobelt and uniaxial tensile plastic geogrid and the parameters of the reinforced soil interface when used as reinforcing materials,indoor tensile tests,direct shear tests and pull-out tests were conducted to obtain the ultimate tensile strength of the reinforcing materials and the friction coefficient of the reinforced soil interface,and the analysis concluded that the reinforcing materials can attenuate the soil softening and improve the strength characteristics of the sand-soil interface;the improvement of reinforced soil strength by geobelt and geogrid is mainly achieved by improving cohesion.（3）Using PLAXIS2D finite element software,the numerical calculation model of reinforced soil retaining wall with geobelt and geogrid as reinforcement materials is established,which proves the feasibility of the design scheme.By comparing the distribution laws of horizontal soil pressure on the wall panel,vertical stress in the wall,lateral displacement and post-construction settlement of the retaining wall panels,and axial force and strain of the reinforcement materials for the contrasting reinforced soil retaining wall,the analysis found that the tensioned reinforcement can significantly reduce the vertical stress in the wall and horizontal stress of the wall panel,but the reinforcement effect is weaker at the bottom of the retaining wall;it pointed out that the reverse-wrapped geogrid contrasting reinforced soil retaining wall is better than the contrasting geobelt reinforced soil retaining wall in controlling horizontal deformation;it confirmed that the connection and anchorage between the contrasting reinforcement and the panle is the key to the structure.（4）Based on the technical and economic comparison,the structure of reinforced soil retaining wall with geobelt is optimized,and the different vertical spacing,horizontal spacing and whether prestress is applied are compared.It is concluded that reducing the horizontal spacing of reinforcement in the middle of retaining wall is the best to control deformation.The existence of the optimal vertical spacing makes the safety and stability of reinforced soil retaining wall reach the maximum;Prestressing can give full play to the reinforcement function of reinforcement materials everywhere,reduce the lateral deformation of wall panels and increase the stability of reinforced soil retaining walls. |
