مجله ی مهندسی عمران شریف

مجله ی مهندسی عمران شریف

مطالعه ی رفتار غیراشباع خاک تثبیت شده ی ماسه‌ای گچ‌دار عراق با سیمان و CKD با استفاده از دستگاه تحکیم اصلاح شده

نوع مقاله : یادداشت فنی

نویسندگان
احمد کامل ابراهیم الکینانی 1
علی اخترپور 1
مصطفی م عبدالحسین 2
1 گروه مهندسی عمران، دانشگاه فردوسی، مشهد، ایران.
2 گروه مهندسی عمران، دانشگاه کوفه، نجف، عراق.
10.24200/j30.2026.68033.3473
چکیده
در پژوهش حاضر، به بررسی رفتار تحکیمی خاک‌های ماسه‌ای گچ‌دار عراق تثبیت‌شده با سیمان و گرد کوره‌ی سیمان(CKD) تحت تراکم‌های ۹۰ و ۹۵ درصد پرداخته شده است. آزمایش‌های آزمایشگاهی با استفاده از تحکیم غیراشباع برای به‌دست‌آوردن منحنی‌های SWRC و ارزیابی نقش مکش در تراکم‌پذیری و نگهداری آب خاک انجام شده است. نتایج نشان داده‌اند که هر دو عامل سیمان و CKD ظرفیت نگهداری آب خاک را افزایش و آثار هیسترزیس را کاهش می‌دهند و مقاومت آن در برابر تراکم و تورم را بهبود می‌بخشند. مدل وان‌گنوختن، تطبیق خوبی با منحنی‌هایSWRC قبل و پس از تثبیت با سیمان و CKD نشان داده است. نتایج به‌دست‌آمده نشان داده‌اند که افزودن 3% سیمان و 5% CKD به ترتیب موجب کاهش هیستریزیس و بهبود منحنیSWRC به‌ویژه در تراکم 95% شده است. همچنین، در تراکم 95% و مکش60 کیلوپاسکال، سیمان به ضریب بهبود 83% و CKD به 33% رسیده است. تجزیه‌وتحلیل SEM بهبود میکروساختاری ناشی از هیدراسیون سیمان و واکنش‌های پوزولانی CKD را تأیید کرده است. یافته‌های اخیر بر اهمیت تثبیت‌کننده‌ها در بهبود ویژگی‌های هیدرولیکی و پایداری بلندمدت خاک‌های ماسه‌ای گچ‌دار عراق در محیط‌های مرطوب تأکید می‌کنند.
کلیدواژه‌ها
تثبیت خاک گچی
منحنی مشخصه‌ی SWRC
ماسه‌ی گچ‌دار عراق
افزودنی‌های سیمانی
گرد کوره‌ی سیمان (CKD)
مکانیک خاک غیراشباع
موضوعات

عنوان مقاله English

Study of Unsaturated Behavior of Stabilized Gypsum Sand Soil from Iraq with Cement and CKD

نویسندگان English

Ahmed Kamil Abraheim Alkinani 1
Ali Akhtarpour 1
Mustafa M. Abdalhusein 2
1 1Department of Civil Engineering, Ferdowsi University of Mashhad, Iran.
2 2Department of Civil Engineering, University of Kufa, Al-Najaf, Iraq.
چکیده English

This research explores the compaction behaviour of Iraqi gypsum-sand soils stabilized with cement and cement kiln dust (CKD) at varying additive percentages (1%, 3%, 5%, and 7%) under different compaction levels (90% and 95%). Laboratory experiments were conducted using a modified oedometer to obtain Soil Water Retention Curves (SWRC) and assess the impact of matric suction on soil compressibility and water retention. The study reveals that both cement (3%) and CKD (5%) significantly improve the water retention capacity of the soil, reduce hysteresis effects, and enhance its resistance to compaction and swelling. These additives positively influence the soil’s water-holding capacity, thereby improving its performance in both saturated and unsaturated conditions. The Van Genuchten model was effectively used to describe the SWRC, demonstrating that cement outperforms CKD in terms of hydraulic behaviour due to the formation of stronger cementitious bonds, which contribute to better soil structure and stability.
Additionally, the improvement analysis highlights that stabilization at higher compaction levels (95%) and under conditions of increased matric suction results in greater effectiveness, with cement-treated soils showing the most significant performance improvement. This is particularly critical for applications in environments where soil behaviour under varying moisture content is a key factor. Furthermore, Scanning Electron Microscope (SEM) analysis confirmed the microstructural enhancements caused by cement hydration and the pozzolanic reactions of CKD, which help form a more stable and cohesive structure at the particle level.
The results showed that adding 3% cement and 5% CKD reduced hysteresis and improved the SWRC curve, especially at 95% density. Also, at 95% density and 60 kPa suction, cement reached an improvement factor of 83% and CKD reached 33%.
The findings underline the importance of both the type of stabilizing agent and the compaction level in improving the hydraulic properties and long-term stability of Iraqi gypsum-rich sandy soils. This research emphasizes the potential of using cement and CKD for soil stabilization, particularly in regions where moisture variability and soil behaviour are significant challenges. These insights contribute to the development of more durable and sustainable soil stabilization techniques in geotechnical engineering.

کلیدواژه‌ها English

SWRC (Soil Water Retention Curve)
Iraqi gypsum sand
cementitious additives
Cement Kiln Dust (CKD)
unsaturated soil mechanics
 
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مجله ی مهندسی عمران شریف
دوره 42، شماره 1 - شماره پیاپی 1
مقالات شماره بهار در حال بارگذاری می باشد
بهار 1405
صفحه 137-141