مطالعه ی آزمایشگاهی اثر مهار برگشتی، افزایش ضخامت مسلح کننده و میخ کوبی در افزایش ظرفیت باربری پی نواری روی خاک ماسه ای

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشیار، دانشکده فنی مهندسی، دانشگاه محقق اردبیلی، اردبیل، ایران.

2 دانشکده فنی مهندسی، دانشگاه محقق اردبیلی، اردبیل، ایران.

چکیده

استفاده از خاک مسلح از زمان‌های بسیار دور در ایران متداول بوده است. امروزه با ساخت سازه‌های سنگین و حیاتی، لزوم استفاده از خاک مسلح بیشتر از گذشته نمایان می‌شود. تحلیل و طراحی سازه‌های خاک مسلح، نیازمند فهم دقیق از رفتار سیستم خاک مسلح و اندرکنش بین مسلح‌کننده‌ها و توده‌ی خاک در برابر بارهای اعمالی می‌باشد. علیرغم اینکه مطالعات بسیاری درزمینه‌ی خاک مسلح انجام‌شده است، ولی تاکنون روش جامعی که بتواند میزان خاک‌برداری و خاک‌ریزی در پروژه‌های خاک مسلح را کاهش دهد، ارائه نشده است. در این پژوهش سعی گردیده تکنیک‌هایی آزمایشگاهی، جهت افزایش بازده مسلح‌کننده در افزایش ظرفیت باربری ارائه شود. در آزمایش‌های انجام‌شده، پی نواری به‌صورت یک ورق فولادی با ابعاد 2×5/7×25 سانتی‌متر و خاک زیر پی در یک جعبه‌ی فولادی با ابعاد 30×25×90 سانتی‌متر شبیه‌سازی گردیده ‌است. در پژوهش حاضر، تأثیر استفاده از مسلح‌کننده به‌صورت مهار برگشتی و انتهای آزاد به‌صورت تک و چندلایه‌ای، ضخامت مسلح‌کننده و نیز تأثیر روش‌های مختلف میخ‌کوبی بر روی مسلح‌کننده موردبررسی قرارگرفته است. نتایج تحقیق نشان می‌دهد تقسیم طول مسلح‌کننده با شرایطی مشخص و استفاده در چندین لایه ظرفیت باربری پی را افزایش می‌دهد. همچنین ایجاد مهار برگشتی پیوسته می‌تواند ظرفیت باربری پی را نسبت به حالت مسلح‌کننده انتهای آزاد تک لایه‌ای حدود 114% بیشتر بهبود بخشد. افزایش ضخامت مسلح‌کننده در حالتی که طول کلی مسلح‌کننده‌ی مورداستفاده با طول مسلح‌کننده در حالت تک لایه برابر می‌باشد در حدود 40% بیشتر ظرفیت باربری پی را افزایش می‌دهد. در تسلیح میخ‌کوبی شده، افزایش ظرفیت باربری تابع موقعیت قرارگیری افقی و قائم میخ‌ها می‌باشند، بطوریکه تغییر در ابعاد و چیدمان میخ‌کوبی می‌تواند ظرفیت باربری سیستم را به‌صورت قابل‌توجهی تغییر دهد. با استفاده از تکنیک مناسب میخ‌کوبی ظرفیت باربری پی خاک مسلح تا حدود 270 درصد نسبت به خاک غیر مسلح افزایش می‌یاید.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

A Laboratory Study of the Effect of Wraparound Anchorage, Increasing Reinforcement Thickness and Nailing in Improving the Bearing Capacity of Strip Foundation on Sandy Soil

نویسندگان [English]

  • Ahad Ouria 1
  • Eliar Heidarli 2
  • Mohammadali Enshaei 2
1 Associate Professor, Faculty of Engineering, University of Mohaghegh Ardabili, Ardabil, Iran.
2 Faculty of Engineering, University of Mohaghegh Ardabili, Ardabil, Iran.
چکیده [English]

In this study, several methods have been experimentally evaluated to increase the efficiency of reinforcements in the bearing capacity of a strip footing on sand. The capacity of the foundation in five different configurations including single and multilayer reinforcements was evaluated with free and wraparound anchored end, different thickness, and nailed with different numbers of nails and patterns. According to the results of these tests, dividing the length of the reinforcement and using it in more layers increases the efficiency of the reinforcement, but this division of the length of the reinforcement has a certain limit that reducing this limit reduces the efficiency. The use of wraparound anchorage caused more interaction between the soil grains and the reinforcement surface and as a result increased the bearing capacity of the foundation. Increasing the thickness of the reinforcements was another parameter studied in this study. Increasing the thickness of the reinforcement caused the bearing capacity to increase.  The results of the experiments show that the pattern of nails has a significant effect on the performance of the reinforced soil.

کلیدواژه‌ها [English]

  • "Wraparound anchorage"
  • "Bearing capacity"
  • "Nailing techniques " . "Optimum reinforcement"
  • "Geotextile"
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