Amin Keshavarz

The need for a safe and economical design of an excavation project is one of the important issues in geotechnics. The sensitivity of the issue becomes more vivid when the depth and width of the excavation is high. Various methods and strategies have been proposed from past to present for stabilizing the excavation wall. DSM piles, sheet pile walls, reciprocated bracing, nailing and tie backs are among the most widely used methods. The tie back method, also known as the anchorage method, is one of the most widely used methods in stabilizing the excavations, especially in deep trenches. Numerous studies have been conducted in this field since the rise of this method. These studies are carried out in the form of implementation,reliability, optimization, scope of application, etc. This dissertation can be included in a series of studies in the form of analysis, design and optimization. Excavation analysis and design are performed using finite element software such as Plaxis with assumption of 2D behavior. In this study, two-dimensional and three-dimensional analyzes with the aim of finding an optimal and low cost design are compared with each other.In this Research three sandy soil of compacted sand, medium-compact and loose sand in three height of 6,12 and 18 meters of excavation and three excavation width of 20,30 and 50 meters used as investigation parameters as to find deformations of heighest point of excavation wall and it’s footer mometum.The results of the study shows that the 3D models represent more realistic models of the excavation behavior. The cantilever behavior of the wall, the width factor of the wall, and the impaction of the applied stresses from the soil, groundwater, and anchors are all seen to bring the results closer to actual behavior.