مطالعه‌ی عددی پارامترهای مقاومتی سیستم میخکوبی با چیدمانهای مختلف (مورد پژوهش: خاکهای مارنی تبریز)
محورهای موضوعی : آنالیز سازه - زلزله
1 - گروه مهندسی عمران، واحد تبریز، دانشگاه آزاد اسلامی، تبریز، ایران
کلید واژه: دیوارهای مسلح, میخکوبی خاک, ضریب اطیمنان, FLAC3D,
چکیده مقاله :
میخکوبی خاک یک روش پایدارسازی، با استفاده از عناصر فولادی مقاوم در برابر کشش است که می‌تواند برای گودبرداری و حفاری شیب‌های تند تحت بارهای استاتیکی و دینامیکی مورد قرار گیرد. این پژوهش به بررسی عددی پارامترهای مقاومتی سیستم میخکوبی در خاکهای مارنی پرداخته است. مطالعه موردی، شامل دیواری به طول 300 متر در شهر تبریز است که به دلیل کوتاهی طول میخ‌ها و تغییرات حین اجرا، در سه نقطه دچار ریزش و ترک‌خوردگی شده است. با استفاده از نرم‌افزارFLAC3D، پنج پیکربندی مختلف مورد تحلیل قرار گرفت و نتایج با مدل آزمایشگاهی یزداندوست مقایسه شد. نتایج نشان داد که در مدل M1با طول یکنواخت میخ‌ها و مدل M2با کاهش تدریجی 10 درصدی طول میخ‌ها از بالا به پایین، توزیع نیروها متعادل نبود. مدل‌های M3و M4 با افزایش طول میخ‌ها در قسمت‌های بالایی و میانی نیز عملکرد مطلوبی نداشتند. در نهایت، مدل M5 با افزایش 20 درصدی طول میخ‌ها در ردیف پایین، بهترین عملکرد را با حداکثر نیروی محوری 169 کیلونیوتن و ضریب اطمینان 44/1 نشان داد. همبستگی بالای نتایج عددی و آزمایشگاهی با ضریب رگرسیون 97/0 برای جابجایی دیوار و 96/0 برای نیروی محوری، صحت مدل‌سازی را تأیید نمود. این مطالعه نشان داد که طراحی مناسب طول و آرایش میخ‌ها، به‌ویژه در قسمت پایین دیوار، نقش حیاتی در پایداری سازه دارد.
Soil nailing is a stabilization method utilizing tensile-resistant steel elements that can be employed for excavation and steep slope construction under static and dynamic loads. This research numerically investigates the resistance parameters of soil nailing systems in marly soils. The case study involves a 300-meter-long wall in Tabriz city, which experienced collapse and cracking at three points due to insufficient nail lengths and construction modifications. Using FLAC3D software, five different configurations were analyzed, and the results were compared with Yazdandoost’s laboratory model. Results indicated that Model M1 with uniform nail lengths and Model M2 with a gradual 10% reduction in nail lengths from top to bottom showed unbalanced force distribution. In addition, Models M3 and M4, which included increased nail lengths in the upper and middle sections, also demonstrated suboptimal performance. Finally, Model M5, incorporating a 20% increase in nail lengths in the bottom row, exhibited the best performance with a maximum axial force of 169 (KN) and a safety factor of 1.44. The high correlation between numerical and laboratory results, with regression coefficients of 0.97 for wall displacement and 0.96 for axial force, validated the modeling accuracy. This study demonstrated that proper design of nail lengths and arrangements, particularly in the lower wall section, plays a crucial role in structural stability.
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