چكيده به لاتين
With the urbanization development and the need to excavation and consequently its stabilization, various methods have been developed to stabilize pits, of which mechanical anchors e.g., the helical anchor due to its resistance against compressive and tensile forces has been used as an anchor to provide the stability of pit walls as well as a deep foundation. The helical anchors including single-helix and multi-helix have been used to resist tensile loading for a variety of structures, such as transmission as well as cell phone towers, and to resist buoyant uplift, such as buried pipelines. This choice depends on various factors such as soil and loading type, availability and installation equipment. The behavior of multi-helical anchors may also depend on the geometry used (i.e., number, diameter and distance of helices). In the last twenty years, several studies have been conducted in the laboratory as well as in the field, to investigate the behavior of multi-helix anchors in various soils. Since the soil seriously suffers by installing these anchors, and the parameters affecting on the torsional anchor are correlated, and the presented ideas are diverse and have significant effects on the design process of these anchors, the numerical modeling methods with their development are reliable to predict the structural and geotechnical behavior of these anchors. Therefore, in this research, through numerical modeling by constructing four types of anchors in sandy soil, the effect of depth, soil density, excavation height, anchor installation depth, increasing anchor length, anchor shaft diameter, relative distance of helical plates on the amount of horizontal displacement of the wall. The numerical modeling has been developed through finite difference FLAC2D software, which was initially carried out to ensure the software accuracy of numerical modeling and its results. It was shown that by reducing the relative distance of the plates and by increasing the shaft diameter of the helical anchors and by increasing the relative density, the maximum displacement of the wall declines. As the density increases, the maximum displacement decreases. By increasing the installation depth of the anchor installations, the maximum displacement of the wall is reduced, although this is subject to the operational circumstances. As the length of anchors increases as a result of more density, the force of anchors decreases. With the increase in the change of excavation height (increasing height), the displacement of the pit wall significantly increases due to the release of more stresses originated from the soil.
