بررسي اثر شعاع انحنا شيرواني‌هاي خاكي ماسه‌يي محدب در پلان در ظرفيت باربري پي‌هاي واقع بر آن‌ها

Numerical Investigation of the Effect of Curvature on the Bearing Capacity of Sandy Convex Slopes

ظرفيت باربري پي‌هاي محدود واقع بر شيرواني‌هاي خاكي محدب موضوعي سه بعدي است كه فرض دوبعدي آن نمي‌تواند جواب‌هاي دقيقي را ارايه كند. بنابراين به منظور اينكه بتوان نتايجي كاربردي و قابل استفاده براي مهندسان در محاسبه‌ي ظرفيت باربري پي‌هاي واقع بر سطح شيرواني خاكي محدب به‌دست آورد، از يك نرم‌افزار اجزا محدود قوي به نام آباكوس، كه قابليت به‌كاربردن مدل جامع خاكي موهر كلمب را در حالت سه بعدي داشته باشد، براي به‌دست‌آوردن اثر انحنا شيرواني‌هاي خاكي محدب در پلان در ظرفيت باربري پي‌هاي واقع بر آن استفاده شده است. چون نتايج براي خاك‌هاي رسي و ماسه‌يي متفاوت است، لذا در اين نوشتار فقط به نتايج حاصل براي خاك‌هاي ماسه‌يي پرداخته شده و اثر ساير پارامترها نيز علاوه بر اثر انحنا بررسي شده است. نتايج حاكي از اين مطلب است كه با افزايش شعاع انحنا شيرواني‌هاي خاكي محدب ظرفيت باربري نيز افزايش مي‌يابد، كه اين نتايج به صورت نمودارهاي كاربردي براي استفاده‌ي مهندسان نشان داده شده است.

The bearing capacity of finite foundations located on slopes that are convex in plan is investigated by three-dimensional models. In this study, we utilized a powerful finite element software, using the Mohr Coulomb constitutive model, in three dimensions, to obtain practical results for the bearing capacity of foundations located on slopes that are convex in plan. The results show that with an increase in the radius of curvature of the convex slopes, the bearing capacity of square foundations located on them also increases. The results are displayed in the form of practical charts for engineer usage. These plots can be utilized for practical purposes by estimating the bearing capacity of equivalent foundations located on straight slopes from limit equilibrium, or finite element codes that are used in soil mechanics, for example, Plaxis software. Although the effect of the radius of curvature on the bearing capacity of foundations is lower than other parameters. When other parameters are obtained with a good degree of precision, these results could be used complementarily for achieving comprehensive results for practical purposes in civil engineering projects. Because Abaqus is a very powerful code that can be used for soil materials, we can trust its calculated results. As the Abaqus code has very advanced techniques for mesh generation, for obtaining results with the most precision, the mesh is generated very carefully with finer elements near the foundation and coarser elements in locations far from the foundation. The primary purpose for generating such mesh is calculation of the bearing capacity of foundations. Not only are the results affected by the radius of curvature of the slope, they also depend on other parameters, like the friction angle of sandy soil, and distance of the foundation from the crest of the slope. Therefore, we studied these parameters in addition to the radius of curvature of the slopes.