ظرفیت باربری پی‌های نواری واقع بر توده سنگ‌های شیل با رفتار رئولوژیک: با در نظرگیری رویکرد احتمالاتی

نوع مقاله : یادداشت فنی

نویسندگان

دانشکده‌ی مهندسی عمران، دانشگاه تبریز، تبریز، ایران.

10.24200/j30.2025.66634.3422

چکیده

وجود عدم‌قطعیت بالا در مقدار خصوصیات مختلف توده‌سنگ می‌تواند پیش‌بینی ظرفیت باربری توده‌سنگ‌ها را با چالش‌هایی همراه سازد. در شرایطی که توده‌سنگ، خواص وابسته به زمان نیز  داشته باشد، این مشکل دوچندان خواهد شد. از این رو، در مطالعه‌ی حاضر، با فرض اینکه سنگ واقع در زیر پی، از نوع شیل است، به بررسی ظرفیت باربری پی‌های نواری با درنظرگرفتن رفتار وابسته به زمان توده‌‌‌سنگ پرداخته شده است. برای این کار، از نرم‌افزار FLAC استفاده شده و مدل ویسکو-الاستوپلاستیک CVISC به توده‌سنگ اختصاص یافته است. همچنین، پارامترهای مقاومتی و رئولوژیکی توده‌سنگ به‌عنوان پارامترهای تصادفی انتخاب شده‌اند. سپس، با استفاده از روش سطح پاسخ، رابطه‌ی پارامترهای ورودی و ظرفیت باربری توده‌سنگ با درنظرگرفتن رفتار وابسته به زمان، تعیین و به هر یک از پارامترهای مذکور، توزیع نرمال و مقادیر میانگین و انحراف معیار اختصاص یافته است. در گام بعد، با استفاده از روش مونت-کارلو و رابطه‌ی محاسبه‌شده، توزیع احتمالاتی برای ظرفیت باربری تعیین شده است. نتایج پژوهش حاضر نشان داده است که پارامتر مدول برشی کلوین و GSI، بیشترین تأثیر را در مقدار ظرفیت باربری داشته و توزیع‌های حاصل از توزیع نرمال تبعیت کرده‌اند. همچنین، با درنظرگرفتن رویکرد احتمالاتی، کاهش 10 درصدی مدول برشی کلوین می‌تواند مقدار ظرفیت باربری توده‌سنگ را 10٪ کاهش دهد. به‌علاوه، حدود 2٪ اختلاف بین نتایج روش‌های قطعی و تحلیلی وجود دارد و در نتیجه، با درنظرگرفتن عدم‌قطعیت، ظرفیت باربری توده‌سنگ کاهش پیدا کرده است.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Bearing Capacity of Strip Foundations on Shale Rock Masses with Rheological Behaviour: Probabilistic Based Approach

نویسندگان [English]

  • Faraz Motamedi Mamaghani
  • Masoud Ranjbarnia
  • Milad Zaheri
Faculty of Civil Engineering, University of Tabriz, Tabriz, Iran.
چکیده [English]

Predicting the bearing capacity of rock masses can be challenging when the values of rock mass properties have high uncertainty. This challenge becomes even greater when the rock mass exhibits time-dependent behavior. Therefore, in this paper, the bearing capacity of strip foundations located on rock masses with time-dependent behavior is investigated. For this purpose, FLAC software is used and the visco-elasto-plastic CVISC model is assigned to the rock mass. Also, the Hoek-Brown criterion constant, uniaxial compressive strength of rock mass, GSI (geological strength index of rock mass), Kelvin shear modulus, Maxwell viscosity, and Kelvin viscosity are selected as random parameters. Initially, using the results obtained from this software and using the response surface methodology, the relationship between these input parameters and the bearing capacity of the rhological rock mass is determined. Then, a normal distribution and mean and standard deviation values are assigned to each of these parameters. In the next step, using the Monte Carlo method, a large number of random numbers are generated and, considering the relationship between the above input random variables and the resulting output (bearing capacity of the rock mass with the time-dependent behaviour), probability distributions for the output of the problem are determined. The results of this research indicate that the Kelvin shear modulus of the rock mass is the most effective parameter in predicting of the value of the bearing capacity, and the resulting distributions follow the normal distribution. Besides, if the uncertainty of the rock mass parameters increases, the standard deviation of the results also increases. Also, the amount of positive skewness also increases. As a result, the probability that the bearing capacity of the rock mass is less than the average value is greater. Thus, in various construction projects, the bearing capacity of rock masses needs to be examined based on probabilistic methods.

کلیدواژه‌ها [English]

  • Bearing capacity of rheological rock mass
  • rock mass
  • probabilistic analysis
  • response surface methodology
  • numerical method

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