Vol.:(0123456789) 1 3 Int J Civ Eng DOI 10.1007/s40999-017-0216-5 RESEARCH PAPER An Investigation on the Formation of Cracks at the Corner Turns of the Modular Block Earth Walls Murat Hamderi 1  · Erol Guler 2  · Ayman Raouf 2   Received: 6 October 2016 / Revised: 27 January 2017 / Accepted: 25 March 2017 © Iran University of Science and Technology 2017 These stresses reduced when the reinforcement stifness increased. It is foreseen that the crack occurrence is less likely to happen under reduced stress. Keywords Segmental modular block walls · TNO DIANA · Cracks · Corner turns · Separation 1 Introduction In the last 3 decades, Geosynthetic Reinforced Soil (GRS) walls have become more common due to their advantages such as cost-efectiveness, high performance, aesthetic appearance, and durability. In practice, such walls are rou- tinely designed using limit-equilibrium analysis [1–3]. Limit-equilibrium analysis methods are very practical in determining the required reinforcement geometry, strength, and all the other properties of GRS walls. For external stability calculations, the Coulomb earth pressure theory, whereas for internal stability calculations, the Rankine fail- ure surface is considered in Federal Highway Administra- tion [2] and National Concrete Masonry Association design recommendations [4]. In general, the deformation behaviour of walls is evalu- ated using a two-dimensional (2-D) plane-strain analy- sis. In most cases, it is considered to be valid when a 3-D stress–strain state problem is simplifed into a 2-D one, especially in the case where the length of the wall is quite long compared to its width. For such walls, it is quite com- mon to implement a fnite-element (FE) analysis. Many research studies are available about the design and behaviour of GRS retaining walls. In the FHWA design manual, some specifc sections have been devoted to the design of GRS walls with complex geometries. These include cases like bridge abutments, superimposed (tiered) Abstract The design manuals for Geosynthetic Rein- forced Soil Retaining Walls include the methodology for various conditions, except the case where the wall has a curved corner turn. Lately, some problems were report- edly associated with these types of walls. One of the typi- cal problems is cracking/separation of the modular blocks. The most common method for analysing the behaviour of reinforced soil walls is a 2-D plane-strain analysis, which is insufcient for the current problem. Therefore, in this study, a 3-D fnite-element (FE) model, that is capable of modelling corner turns, has been established. The main elements of the model are modular blocks, interface ele- ments, soil, and reinforcements. As a frst step, the perfor- mance of the FE model was evaluated by comparing the stress–strain response of a laboratory-scale wall with its counterpart in the FE program. Later, a large-size modular block wall model was created and run with various input parameters. The modelling results revealed that the rein- forcement stifness and the soil modulus are efective in the separation and cracking of blocks. It is considered that the cracking of blocks is related to an excessive stress build-up. Electronic supplementary material The online version of this article (doi:10.1007/s40999-017-0216-5) contains supplementary material, which is available to authorized users. * Murat Hamderi hamderi@tau.edu.tr Erol Guler eguler@boun.edu.tr Ayman Raouf aymanraouf12@gmail.com 1 Faculty of Engineering, Turkish-German University, Istanbul, Turkey 2 Faculty of Engineering, Bogazici University, Istanbul, Turkey