Field Experiment And Numerical Analysis Of Single Stage Ultra-high Reinforced Retaining Wall

With the vigorous development of infrastructure in China and the development and utilization of slope land resources,a large number of deep excavation and high filling retaining wall projects will be required.Reinforced soil retaining walls have been widely used as a low-cost,aesthetically pleasing,and earthquake resistant retaining structure,and there have been many related studies.However,there is still relatively little research on single stage reinforced soil retaining walls with a height exceeding 20 meters.In response to the problem of stress deformation characteristics and failure characteristics of reinforced soil retaining walls,this article relies on a 20 meters single stage reinforced soil retaining wall project in Zhejiang Province.Field testing and numerical simulation methods are used to analyze the distribution and variation rules of soil pressure,soil deformation,and reinforcement tension of tall reinforced soil retaining walls.The failure mechanism and mode are explored,and the mathematical expression of the fracture surface is obtained by fitting.The stiffness of the reinforcement material is discussed through numerical simulation The effects of factors such as reinforcement spacing,reinforcement length,panel type,and groundwater level height on the displacement,stability,and reinforcement tension of reinforced soil retaining walls are summarized as follows:(1)According to on-site measurements,it can be seen that the horizontal displacement of the reinforced soil retaining wall surface is in a bulging shape,and the strain of the reinforcement material in each layer of the reinforced body is distributed as a single or double peak value;There are two areas where the vertical earth pressure inside the reinforced body increases significantly compared to the self weight earth pressure,and the horizontal earth pressure also follows a similar pattern;The horizontal earth pressure near the wall is smaller than the horizontal earth pressure far from the wall;The tensile force of each layer of reinforcement exhibits a single peak or double peak distribution.(2)According to on-site measurements,it can be seen that the shape of the potential fracture surface is similar to the 0.3H method curve,but the lower inclination angle of the fracture surface is smaller,and the distance from the upper part to the wall panel is larger,about 0.5H.According to numerical simulation analysis,it can be concluded that for this example of reinforced soil retaining wall,when the wall height is less than 14 meters,the potential failure mode of the retaining wall mainly manifests as internal failure,and the potential fracture surface is divided into two sections from near the wall toe and develops upwards to the top of the reinforced body;When the wall height is greater than 14 meters,the potential failure mode of the retaining wall mainly manifests as sliding failure;The potential fracture surface of the retaining wall obtained from numerical simulation analysis is in good agreement with the measured results.(3)The bottom of the reinforced soil retaining wall should use a geogrid with high stiffness;Reducing the spacing between grids can improve the internal stability of the retaining wall;Increasing the length of the grille can improve the external stability of the retaining wall;For high reinforced soil retaining walls,adopting modular panels or integral panels is more suitable;The stability of the retaining wall decreases with the increase of groundwater level,and the rate of decrease increases with the increase of groundwater level.