تأثیر بار ترافیکی بر گودبرداری نگهداری شده توسط انجماد مصنوعی زمین؛ مطالعه موردی: قطار شهری تبریز

نوع مقاله : Articles

نویسندگان

دانشگاه تبریز

چکیده

روش انجماد مصنوعی زمین به عنوان یک روش بدیع مطرح می­گردد که نه تنها از لحاظ فنی و اقتصادی قابل قبول است بلکه دوست­دار محیط زیست بوده و در تمامی انواع خاک­ها و شرایط آب زیرزمینی قابل استفاده است. هدف از این مطالعه، تحلیل و طراحی مکانیکی دیوار خاک منجمد تحت تاثیر کاهش دما و عبور بار ترافیکی می­باشد. در این مطالعه با استفاده از مدل رفتاری موهر- کولمب اصلاح شده که با بهره­گیری از نتایج آزمون­های آزمایشگاهی بر روی خاک منجمد، صحت­سنجی شده است، به شبیه­سازی سه­بعدی اجزای محدود دیوار خاکی منجمد و بررسی پارامتری آن توسط نرم­افزار آباکوس پرداخته شده است. لازم به ذکر است که این پژوهش در قالب یک مطالعه موردی صورت گرفته و تمامی نمونه­های آزمایشگاهی از گمانه­های مطالعاتی خط 2 قطار شهری تبریز به دست آمده­اند. مطابق نتایج آزمایش­ها، رفتار نرم شونده در تمامی نمونه­های خاک منجمد به وضوح مشاهده می­شود و نمودارهای تنش-کرنش یک قله (Peak) و یک حالت پس­ماند (Residual) از خود نشان می­دهند. نتایج آزمایش سه­محوری بر روی خاک منجمد نشان می­دهند که با کاهش دما مقاومت برشی خاک ماسه­ای بددانه­بندی شده منجمد به طور قابل ملاحظه­ای افزایش می­یابد.  نتایج تحلیل­های عددی نشان می­دهند که تغییرمکان جانبی دیوار خاک منجمد تحت تاثیر گودبرداری به سمت داخل گود در مقطع وسط دیوار بیشتر از مقطع تکیه­گاه دیوار بوده و تاثیر عبور بار ترافیکی بر روی مقطع وسط دیوار و افزایش تغییرمکان جانبی آن بیشتر از مقطع تکیه­گاه دیوار می­باشد. همچنین قابل ملاحظه است که کاهش دما از  تا  تاثیر قابل ملاحظه­ای بر کاهش تغییرمکان جانبی دیوار خاک منجمد در مقطع تکیه­گاه ندارد (حدود 2 تا 3 %)، در حالی که در مقطع وسط دیوار کاهش دما در محدود مذکور تا حدود 13% منجر به کاهش تغییرمکان جانبی دیوار خاک منجمد به سمت گود می­گردد.The Effect of Traffic Load Excavation Supported by Artificial Ground Freezing: A Case Study of Tabriz SubwayMahzad Esmaeili-Falak1 and Hooshang Katebi2* 1. Ph.D. Candidate in Geotechnical Eng., Faculty of Civil Eng., University of Tabriz, Tabriz, Iran 2. Associate Professor, Geotechnical Eng. Dept., Faculty of Civil Eng., University of Tabriz, Tabriz, Iran, * Corresponding Author, email: Katebi@tabrizu.ac.irKeywords: Artificial Ground Freezing (AGF), Finite Element Method (FEM), Triaxial Compressive Test, Traffic Load, Tabriz Subway.--English abstract is in the final page of the pdf file--

کلیدواژه‌ها


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