Experimental And Numerical Analysis Of Reinforced Soil Retaining Walls

Retaining structures are use in almost every highway and geotechnical engineering project.These structures include the construction of retaining walls and the use of soil reinforcement.The development of techniques of soil reinforcement represents a great achievement in geotechnical and highway engineering.Soil reinforcement is usually achieved through the use of geosynthetic materials and soil admixtures and geosynthetic materials are chosen over traditional reinforcement materials because they provide advantages that traditional reinforcement lacks.In some cases,prior to the construction retaining walls,numerical analysis is performed.Numerical analysis with advanced software has certain advantages over analytical and experimental analysis because numerical analysis gives us the ability to study the interaction between soil-reinforcement in different scenarios and conditions before the structure is actually built.Numerical analysis also helps engineers and contractors decide on which construction materials,material setup and construction method are most suitable for a particular location.In this thesis,the author firstly presents an experimental study of a reinforced soil retaining wall.Secondly,presents a numerical study of a reinforced soil retaining wall.Thirdly,a comparison is made between experimental and numerical analysis and lastly the conclusions found in both studies are presented.For the experimental study,the author used an experiment boxes with different reinforcement setup in order to better understand the deformation behaviour of the soil and the wall.It was found that both the reinforcement length and spacing are major factors contributing to the overall performance of the wall.The numerical analysis was also performed with a variety of reinforcement and soil properties and was of a larger scale compared to the experimental analysis where a more extensive range of conditions and parameter were studied.Among other findings,the study found that the magnitude of wall face deflection when the backfill soil angle of internal friction is between is above 20° is very small but the wall face deflection significantly increase with a backfill soil angle of internal friction blow 9°;It was found that the high reinforcement tensile stress was caused by the compaction technique and the high stiffness values of the reinforcement materials;Compaction effects are higher in reinforced walls with smaller reinforcement stiffness values as opposed with those with higher reinforcement stiffness values;At lower altitudes,higher stiffness values caused higher lateral earth pressure as opposed to the pressures registered at higher altitudes;The experimental and numerical analysis showed that highest wall face displacement values are found at H/2.This is due to the effect of the surcharge load which was transferred directly to this area in the form of a hyperbolic failure plane;Longer reinforcement contributed to higher soil pressures which caused higher magnitudes of wall face deflection.The comparison between the experimental and numerical analysis of the wall did not focus on the magnitude of deflection values but rather on the pattern of wall face and backfill deflection patterns given that the experimental analysis was much smaller in size compared to the numerical analysis.