Parametric Study On Behaviour Of Reinforced Soil Walls With Combined Horizontal And Vertical Geosynthetics

Hadi Khabbaz, Binod Shrestha and Behzad Fatahi

The reinforced soil system employing geogrids, as a cost effective reinforcement technique, has come to play an important role in a variety of civil and geotechnical engineering applications. In regular reinforced soil walls, the reinforcements are usually laid horizontally in the soil. In this study, the behaviour of reinforced soil retaining walls with combined horizontal and vertical reinforcements are investigated experimentally as well as numerically. The results, indicating the effects of vertical reinforcement inclusion, are compared to conventional reinforcing types under static and dynamic loads. The performance of retaining walls employing vertical reinforcement in conjunction with horizontal reinforcement is convincing from the results of the shake table tests conducted by the authors. In this paper, PLAXIS, well-known geotechnical software, is used for conducting a series of parametric studies on behaviour of reinforced soil walls under construction and subject to earthquake loading, incorporating the vertical reinforcement. The vertical reinforcement layout and its strength are among the major variables of the investigation. The geometry of the model, soil properties and reinforcement characteristics have been kept identical in all different cases selected for parametric studies. The performance of the wall is presented for the facing deformation and crest surface settlement, lateral earth pressure, tensile force in the reinforcement layers and acceleration amplification. The vertical deformation, horizontal deflection, reinforcement force and earth pressure develop drastically under earthquake loading compared to the end of construction. The results show that these variables are considerably reduced when incorporating the vertical reinforcement in the system. In addition, the findings suggest better performance and higher structural safety for reinforced soil walls, when employing this proposed orthogonally horizontal-vertical geosynthetics.