بررسی آزمایشگاهی رفتار شمع‌های پیچشی تحت بارگذاری منوتونیک در سرعت‌های مختلف بارگذاری

نوع مقاله : یادداشت فنی

نویسندگان

1 دانشکده‌ی مهندسی عمران، دانشگاه صنعتی شاهرود، شاهرود، ایران.

2 دانشکده‌ی مهندسی عمران، آب و محیط‌زیست، دانشگاه شهید بهشتی تهران، ایران.

چکیده

استفاده از شمع‌های پیچشی، یکی از روش‌های نوین بهسازی است، که به‌دلیل ویژگی‌های منحصر به فرد آن‌ها، که مهم‌ترینش دوستدار محیط‌زیست‌بودن است، در سال‌های اخیر رواج بسیاری پیدا کرده است. از آنجایی که در هنگام واردشدن نیرو‌های فشاری، شافت شمع‌ نقش اساسی و در هنگام واردشدن نیرو‌های کششی، بال‌ها (پره‌ها) نقش اساسی در تحمل نیرو‌های مذکور را ایفا می‌کنند، بنابراین پیش‌بینی رفتار شمع‌ها تحت بارگذاری کششی پیچیده‌تر از بارگذاری فشاری است. در پژوهش حاضر، به‌منظور پیش‌بینی رفتار کششی شمع‌های پیچشی تحت سرعت‌های بارگذاری مختلف و همچنین بررسی افزودن پره‌ی دوم به شمع پیچشی تک‌پره، با استفاده از دستگاه مدل‌سازی فیزیکی g 1، در دو تراکم نسبی بالا (95٪) و پایین  (45٪) مطالعه شده است. نتایج به‌دست‌آمده نشان می‌دهند که در آزمایش‌های مونوتونیک، ظرفیت باربری نهایی با افزایش سرعت بارگذاری تا حدود 56٪ کاهش یافته است؛ از طرف دیگر، با افزایش تراکم نسبی و افزایش تعداد پره‌ها، ظرفیت باربری نهایی به ترتیب تا حدود 468 و 54 درصد افزایش پیدا کرده ‌است.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Laboratory Investigation of the Behavior of Helical Piles under Monotonic Loading at Different Loading Speeds

نویسندگان [English]

  • Seyed Sajjad Hosseini 1
  • Mohsen Keramati 1
  • Reza Hoseinpour 2
1 Faculty of Civil Engineering of Shahrood University, Shahrood, Iran.
2 Faculty of Civil Engineering of Shahid Beheshti University, Tehran, Iran.
چکیده [English]

Today, one of the primary challenges faced by geotechnical engineers in dealing with problematic soils is to choose a suitable improvement method that, in addition to strengthening the soil, does not cause harmful damage to the environment. Helical piles are a new method that has become very popular in recent years due to the unique features of this type of pile, the most important of which is that it is environmentally friendly. Due to their unique shape and section (having one or more helices along the shaft of the pile), Helical piles have a higher load capacity than usual concrete piles. Among the advantages of using this type of pile, it can be a short installation time with minimal noise and vibration (no need to vibrate for installation), is Easy to implement due to limited access, lightweight, reduction of disturbance soil during installation, and poses less environmental risks and is compatible with nature. According to past studies, it has been found that the current knowledge of the performance of this type of pile and the methods of predicting and determining the bearing capacity currently need to be improved, and this shows the necessity of researching the behavior of these piles. This research, to predict the tensile behavior of Helical piles under different loading speeds and also to investigate the addition of a second helix to a single-helix Helical pile, using the 1g physical modeling device, in two cases of high (95%) and low (45%) relative densities, has been studied. The results obtained in this study show that the effect of relative soil compaction on improving the bearing capacity of the soil was more significant than the loading speed and the number of helices. According to the results of the monotonic tests, the final bearing capacity decreased by about 56% with increasing loading speed; on the other hand, by increasing the relative density and increasing the number of helices, the final load capacity increased, respectively by about 468% and 54%.

کلیدواژه‌ها [English]

  • Helical Pile
  • Physical Modeling
  • Monotonic Test
  • Loading Speed
  • Ultimate Capacity

مراجع

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