بررسی رفتار برشی ماسه کربناته جزیره خارک در حالت سیمانی سازی شده به صورت شبه طبیعی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 گروه مهندسی عمران، دانشکده مهندسی، دانشگاه فسا، فسا، ایران

2 گروه مهندسی عمران، دانشکده مهندسی، دانشگاه فسا، فسا، ایران.

چکیده

در این پژوهش به بررسی تاثیر سیمانی شدن طبیعی بر رفتار برشی ماسه­ کربناته جزیره خارک پرداخته شده است. بدین منظور از یک روش شبیه سازی سیمانی شدن خاک در طبیعت برای سیمانی سازی کردن نمونه­های این خاک استفاده گردید. اهمیت این روش سیمانی سازی در قابلیت آن به ‌عنوان جایگزینی برای نمونه‌های دست نخورده سیمانی شده طبیعی است که در عمل به دست آوردن آن‌ها سخت و پر هزینه است. نمونه­های سیمانی سازی شده با این روش و نمونه‌های غیر سیمانی با استفاده از آزمایش برش مستقیم تحت برش قرار گرفته و نتایج با هم مقایسه و تحلیل گردیدند. همچنین تاثیر متغیرهای مدت زمان عمل­آوری ماسه سیمانی شده و درصد تراکم بر رفتار برشی ماسه­ این محل بررسی شد. مشاهده گردید که سیمانی کردن ماسه خارک باعث افزایش مقاومت به ویژه در تنش‌های قائم بزرگ‌تر و همچنین کاهش تمایل به اتساع گردید. سیمانی کردن خاک باعث افزایش زاویه اصطکاک داخلی گردید در حالی که مشاهده گردید که با سیمانی شدن، چسبندگی خاک میتواند افزایش یا کاهش یاید و یا بدون تغییر بماند. افزایش زمان عمل آوری خاک سیمانی شده خارک همواره باعث افزایش قابل توجه چسبندگی و تغییر ناچیز در زاویه اصطکاک داخلی آن گردید. همچنین مشاهده گردید که افزایش تراکم خاک سیمانی شده خارک می‌تواند منجر به کاهش، افزایش و یا بدون تغییر ماندن چسبندگی آن شود در حالی که عمدتاً باعث افزایش زاویه اصطکاک داخلی آن می‌گردد. عوامل محتمل در ایجاد تغییرات یاد شده معرفی شده و تاثیر هر یک از آن‎ها بررسی گردید.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Shearing behavior of Carbonate Sand of Khark Island Cemented by a Pseudo-natural Method

نویسندگان [English]

  • Mohammad Reza Arvin 1
  • Ali Masoomi 2
  • Mohsen Ajdari 2
1 Civil Engineering Department, Faculty of Engineering, Fasa University, Fasa, Iran.
2 Civil Engineering Department, Fasa University
چکیده [English]

In the present study, the effect of natural cementation on the shearing behavior of carbonate sand of Khark Island, south of Iran, has been investigated. To do so, a pseudo-natural cementation method was employed. The importance of this technique lies in its suitability as a substitute for undisturbed samples of cemented carbonate soil that are hard and costly to prepare. Uncemented and cemented samples provided by this method were tested using direct shear apparatus and the results were analyzed and compared to one another. Furthermore, the effects of factors such as curing time and relative compaction on the shearing behavior of the Khark sand were studied. It was observed that cementation results in the rise of the shearing resistance, in particular at high vertical stresses, and leads to a decline in the tendency of soil to dilation. While cementation led to growth in the internal friction angle of soil, it may cause an increase, a decrease, or no change in the cohesion of the Khark sand.  The increase in curing time led to a considerable rise in the cohesion and a minor change in the internal friction angle of the cemented soil. Furthermore, results showed that as the relative compaction of the investigated cemented carbonate soil goes up, the cohesion of the soil might increase, decline, or stay unchanged while the internal friction angle always increases. Factors that are likely to contribute to the development of the behavior stated earlier were introduced and their effects were discussed thoroughly.

کلیدواژه‌ها [English]

  • Carbonate Sand
  • Pseudo-static cementation
  • Direct Shear Test
  • Shear Strength
  • Khark Island
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