ارزيابي عددي عوامل موثر در پايداري داخلي ديوارهاي خاك مسلح با مصالح ژئوسنتتيكي و مقايسه با روش‌هاي ساده آشتو و سختي K

Numerical eva‎luation of influential factors in internal stability of geosynthetic reinforced soil walls and comparison with AASHTO simplified and K-stiffness method

مهندسي عمران

Polymeric materials are considered one of the emerging technologies in civil engineering with major applications in Geotechnical engineering known as geosynthetic reinforced soil (GRS). Compared to the traditional retaining structures, the GRS systems have benefits including a reduction in construction cost and time, low-cost material recycling, and simplicity of construction that can be performed by unskilled labor. These advantages have led to an increase in research activities to better understand the performance of GRS and eva‎luate the influential factors on the behavior of these structures. Although the design principles of these walls in terms of external stability share many similarities with conventional retaining walls in civil engineering, the differences in the internal response become one of the distinguishing features of GRS. Therefore, internal stability is of great importance in the design of these structures and is recognized as one of the distinguishing aspects of various design methods. In these methods, determining the maximum load on the reinforcement is considered a decisive factor in internal design. In this study, the three-dimensional modeling of a 7.92-meter-high GRS with a modular facing block is conducted using Abaqus software. The Mohr-Coulomb model was assumed for the backfill, while a linear elasticity model was used for the geogrid. In the simulations, three criteria have been chosen for performance eva‎luation including lateral displacement of the wall, load, and strain on the reinforcements. A comparison of the maximum induced load in the reinforcements is compared with two design methodologies of K-stiffness and the simplified AASHTO. The Finite Element modeling results revealed that the maximum load generated in the reinforcements in this study was lower than that obtained from the simplified AASHTO method and higher than that from the K-stiffness method. To improve wall performance, the effects of soil modulus of elasticity (assumed values of 50, 45, 40, and 55 MPa), cohesion (assumed values of 3, 1.2, and 6 kPa), friction angle (assumed values of 38.5, 35, 33, and 42 degrees), and dilation (assumed values of 14, 12, 10, and 16 degrees) on the internal stability of the soil were examined. An increase in the modulus of elasticity, friction angle, cohesion, and dilation angle of the soil within the specified ranges resulted in a reduction of approximately 7.5%, 57%, 94%, and 1.5%, respectively, in the maximum strain of the eleventh reinforcement layer. Additionally, the behavior of the wall beyond the serviceability conditions was examined. The presence of surface loads altered the distribution of forces acting on the reinforcements.

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