A 3D finite element analysis of the modular block retaining walls with corner turns

Abstract

The design manuals for Geosynthetic Reinforced Soil retaining walls include the methodology for various conditions except the case where the wall has curved corner turns. Lately, there has been an increase in the frequency of problems associated with these types of walls. One of the typical problems is cracking/separation of the segmental blocks. The most common method for identifying the cause of problems is a 2D plain-strain analysis which is insufficient for the current case. Therefore in this study, a more robust modeling approach was considered. A 3D finite element (FE) model which is capable of modeling corner turns was created. The main elements of the model are modular blocks, interface layers, soil and geosynthetic reinforcements. As the first step, a base model was defined. The base model included reinforcements with the lowest stiffness. The base model was evaluated in terms of block displacements and stresses. In the other models, reinforcement stiffness and the soil modulus were increased or decreased to evaluate its effect on block displacements and stresses. According to the modeling results, the elastic modulus of the reinforcements and the soil modulus are very effective on block separation and cracking. The separation of blocks could be decreased by increasing the reinforcement stiffness and proper soil compaction. It is considered that the cracking of blocks was related to excessive moments developing in those blocks. The moments are reduced when the reinforcement stiffness was increased. It can be concluded that the cracking of blocks is less likely to happen under reduced moments.