بررسی اندرکنش جریان آب زیرزمینی شهری و ساخت دیوارهای آب‌بند بتنی زیرسطحی با رویکرد مدلسازی عددی (مطالعه موردی: شهر کربلا، عراق)

نوع مقاله : مقاله پژوهشی

نویسندگان

1 استادیار/ گروه مهندسی و مدیریت آب، دانشگاه تربیت مدرس، تهران، ایران.

2 پژوهشگر/ پژوهشکده مهندسی و مدیریت آب، دانشگاه تربیت مدرس، تهران، ایران.

3 مهندس ژئوتکنیک/ شرکت خدمات بهسازی خاک سامان‌پی، تهران، ایران.

چکیده

در طرح‌های عمرانی شهری، اندرکنش جریان آب‌های زیرزمینی و سازه‌های زیرسطحی از جمله دیوارهای آب‌بند، حائز اهمیت است. استفاده از رویکرد مدلسازی برای بررسی این اندرکنش‌ها می‌تواند در برنامه‌ریزی برای اجرا و پیش‌بینی راهکارهای کاهش اثرات نامطلوب راهگشا باشد. در این مطالعه، کد عددی MODFLOW با بسته HFB جهت شبیه‌سازی سه‌بعدی سیستم آب زیرزمینی یک محدوده شهری واقع در شهر کربلا، کشور عراق، با در نظرگرفتن لایه‌بندی و ناهمگنی زمین‌شناسی منطقه و دیوارهای آب‌بند ساخته شده، به کار رفته است. دیوارهای آب‌بند بتنی با عمق 40 متر با هدف کاستن موضعی سطح تراز آب زیرزمینی برای ساخت اماکن در زیر سطح زمین اجرا شده‌اند. در فرآیند واسنجی و اعتبارسنجی، از داده‌های اندازه‌گیری سطح تراز آب زیرزمینی در 28 چاه مشاهداتی از بهمن‌ماه 1395 تا مهرماه 1397 استفاده شده است. هدف مورد نظر، بررسی اندرکنش جریان آب‌های زیرزمینی و ساخت آب‌بندهای بتنی مبتنی بر طرح‌های توسعه است. نتایج نشان می‌دهد که در توسعه فازهای موردنظر، تغییرات سطح تراز آب زیرزمینی تا بیش از یک متر نیز نسبت به شرایط قبل از توسعه در پشت دیوارهای آب‌بند رخ می‌دهد. برای نمونه، در شرایط فاز ساخته شده، تغییرات سطح تراز آب زیرزمینی بین 55/0- (حدأکثر افت) تا 44/0 متر (حدأکثر افزایش) می‌باشد در حالی‌که با تکمیل کامل فازها، این تغییرات بین 06/1- (حدأکثر افت) تا 14/0 متر (حدأکثر افزایش) خواهد شد. ممانعت از ورود آب به بخش‌های تحتانی اماکن و حفظ پایداری سازه‌های مجاور از مواردی است که باید با اتخاذ راهکارهای فنی و مدیریتی پیشنهاد شده در این مطالعه مدنظر قرار گیرد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Investigation on urban groundwater flow and construction of subsurface concrete cutoff walls interaction using a numerical modeling approach (case study: Karbala city, Iraq)

نویسندگان [English]

  • Hamed Ketabchi 1
  • Davood Mahmoodzadeh 2
  • Hamid Reza Elahi 3
1 Assistant Professor, Water Engineering and Management Deptment, Tarbiat Modares University, Tehran,
2 Researcher, Water Engineering and Management Research Institute, Tarbiat Modares University, Tehran, Iran.
3 Geotechnical Engineer, Samanpey Soil Improvement Services Company, Tehran, Iran.
چکیده [English]

In urban development projects, it is important the interaction of groundwater-flow and subsurface-structures, including cutoff-walls. Using a modeling approach to investigate these interactions can be helpful in planning to implement and strategies to reduce the adverse-effects. In this study, the numerical-code MODFLOW has been used with HFB package to simulate the three-dimensional groundwater-system of an urban area in Iraq, taking into account the geological layering and heterogeneity and the constructed cutoff-walls. These 40-meter-deep concrete cutoff-walls have been constructed with the aim of locally groundwater-level reduction to provide an ability to build the designed constructions under ground-level. For calibration and validation of model, the measured data of groundwater-level in 28 observation wells from February 2016 to September 2018 have been used. The aim is to investigate the interaction between the construction of subsurface concrete cutoff-walls and groundwater-system based on development plans. The results show that in the development of considered phases, an increase or decrease in groundwater-level can occur up to more than one-meter compared to pre-development conditions next to cutoff-walls. For example, under the constructed phase condition, the groundwater level changes are between -0.55 (maximum drop) to 0.44 meters (maximum increase) while with the completion of all phases, these changes are between -0.06 (maximum drop) to 0.14 meters (maximum increase), respectively. Preventing the water entering to the lower parts of constructions and maintaining the stability of adjacent structures are some of the issues, which should be observed considering the technical and managerial solutions suggested in this study.

کلیدواژه‌ها [English]

  • Numerical simulation
  • Groundwater
  • Concrete cutoff walls
  • Subsurface structure
  • Aquifer heterogeneity
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