EXPERIMENTAL STUDIES ON PHYSICAL MODEL OF A ROAD EMBANKMENT REINFORCED WITH GEOSYNTHETICS AND VERIFYING THROUGH PLAXIS SOFTWARE VER 8.6

Abstract

It is a well known fact that soil is a weak material in tension. It is a material that can bear pressure and shear loads but is not stable in front of tensile loads. When it comes to road embankments,weak subgrades are a common problem in road construction. Whether it is a temporary access road or a permanent road built over a weak subgrade, a large deformation of the subgrade can lead to deterioration of the paved or unpaved surface. Due to less shear strength and high compressibility of soft soils, construction of soil embankment on these types of soils leads to problems such as big and non-uniform settlements. Reinforcing soil is one of the effective and trustable method for improvement and treatment of soil properties. Soils reinforcements are composite materials which include elements that can bear tensile loads. Soil reinforcements are used at different issues such as earth dams, slopes or retaining walls and even on stabilization of soil layers under shallow foundation or embankments of roads. Usage of geosynthetics for increasing height of embankments and their stability has been increased significantly in recent years. Using geosynthetics cause decrease of tensile weaknesses and make the soil more stable by decreasing the settlement of it. Geosynthetics reinforcements can be divided into groups of geo-membranes,geo textiles, geo-grids, geo-nets and geo-composites. They are used vastly because of economic reasons and easy application at reinforcing structures like embankments, dams and slope. Due to inceasing traffic at recent years, many of road embankments have been made on soft soils. As a consequence of this, engineers have been encountering different problems such as settlement and instability of slopes, so,we go vi for geotextiles as a trustable material for reinforcing and improving the soil properties. Geosynthetics reinforcement has special effect on increasing the safety factor of slopes. A physical model is prepared in the laboratory which includes the similarity of model size and material used in test and test is performed to examine the failure mechanism occurred by the movement of vehicles on the road. Numerical Modelling has also been done to analyze the deformations and stability of the road slope using PLAXIS 2D software. The study shows that geogrids are an effective tool to enhance the stability of the road embankment. They make the soil stronger in tension. They reduce the deformation of the slope. They restrain the movement of the slope in horizontal direction thus, enhancing the stability. It shows a comparison between the unreinforced and the reinforced slopes.