ارزيابي عددي و تحليلي ظرفيت باربري سيستم كيسه- خاك با مقطع نيم‌بيضي تحت بارگذاري قايم

Numerical and Analytical Evaluation of the Bearing Capacity of a Half-Oval Soil-Bag System under Vertical Loading

هدف اصلي اين نوشتار، بررسي تاثير فرم هندسي سيستم كيسه- خاك با مقطع نيم‌بيضي در بيشينه‌ي ظرفيت باربري، تحت بارگذاري قايم است. در اين مطالعه، در ابتدا با استفاده از روش تحليلي، بيشينه‌ي ظرفيت باربري سيستم كيسه- خاك، تحت فرم هندسي نيم‌دايره مورد بررسي قرار گرفته و سپس مقدار بيشينه‌ي ظرفيت باربري سيستم كيسه- خاك، با فرم هندسي جديدي به شكل نيم‌بيضي ارايه شده است. در ادامه، شبيه‌سازي رفتار مكانيكي سيستم كيسه- خاك، با مقاطع نيم‌بيضي و نيم‌دايره، با استفاده از روش المان محدود در حالت سه بعدي مورد توجه قرار گرفته است. نتايج بررسي ها نشان مي دهند كه با افزايش پارامتر هندسي خروج از مركزيت در كيسه با مقطع نيم‌بيضي و زاويه‏ي اصطكاك داخلي ماسه، ظرفيت باربري قايم سيستم كيسه- خاك تحت بارهاي خارجي افزايش مي يابد. از اين رو، انتخاب فرم هندسي مناسب براي مقطع كيسه مي تواند ظرفيت باربري آن را تا حد قابل توجهي تقويت كند.

The main goal of this paper is to evaluate the effect of the geometric form of a semi-elliptical cross-section on the maximum bearing capacity of a soil-bag system under vertical loading. In the present research, the maximum bearing capacity of a soil-bag system in a geometric semi-circular form is initially studied using an analytical method. Then, the maximum bearing capacity of the soil-bag system is presented by a new geometric form of semi-elliptical shape. Also, the mechanical behavior of the soil-bag system is analyzed using ABAQUS finite element software in a three-dimensional state, to determine the maximum capacity of its loading with semi-elliptical and semi-circular cross-sections. Results show that when the value of the semi-elliptical eccentric and internal friction angle of the soil increases, the bearing capacity of the soil-bag system, influenced by external loads, will also increase. Therefore, choosing a suitable geometric form can increase its bearing capacity to a great extent. Also, considering boundary conditions in semi-elliptical form, the required surface to construct a polymeric bag, in order to constrain the soil, decreases significantly and, in this respect, a significant saving will occur in the consumed materials. By increasing the vertical displacement of the soil-bag system, the circumference strain of the polymeric bag increases. The yield strain of the polymeric bag was considered to be 0.25. Results of the analytical method showed that when the semi-circular cross-section changes into a semi-elliptical one, the vertical bearing capacity of the soil-bag system will increase by 6.68%. Other characteristics of the soil bags, such as absorption of vibrations resulting from traffic load, can be addressed.