مطالعه عددی تأثیر دیوار دیافراگمی در کاهش نشست‌های ناشی از تونل‌سازی مکانیزه

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشگاه تربیت مدرس، تهران، ایران.

2 گروه مکانیک خاک و پی، دانشکده مهندسی عمران و محیط زیست، دانشگاه تربیت مدرس، تهران، ایران

چکیده

جابه‌جایی­‌های ناشی از حفاری تونل در سطح و عمق زمین در صورت عدم کنترل می‌­تواند برای سازه­‌های سطحی و زیرساخت­‌های شهری خطرآفرین باشد. از این ­رو، در هنگام تونل­‌سازی در محیط شهری از روش‌­های متنوعی برای کاهش نشست­‌ها استفاده می‌­شود. یکی از این روش‌­ها، استفاده از دیوار دیافراگمی است. در این مطالعه تأثیر استفاده از دیوار دیافراگمی در کاهش جابه‌جایی‌­های ناشی از حفاری تونل متروی مادرید با حضور لایه ضخیم خاک دستی بررسی گردیده ­است. برای این منظور حفاری مکانیزه تونل متروی مادرید به صورت گام به گام و سه بعدی در نرم‌­افزار المان محدود آباکوس مدل‌­سازی گردیده­ است. در این مدل­‌سازی­‌ها مولفه‌­های مختلف TBM یعنی فشار اعمالی به جبهه کار، تزریق دوغاب در پشت سگمنت‌­ها، اضافه ­حفاری ناشی از اختلاف قطر کله­ حفار و سپر در نظر گرفته شده ­است. دیوار دیافراگمی نیز به صورت سه بعدی مدل­‌سازی گردیده ­است. پارامترهای متغیر این مطالعه مدول الاستیسته دیوار، طول دیوار، زبری بین دیوار و خاک، فاصله دیوار از محور تونل و دانسیته دیوار است. نتایج مطالعه نشان می‌­دهد در بین پارامترهای مختلف تأثیرگذار، مدول الاستیسیته دیوار و فاصله آن از محور تونل بیش­ترین تأثیر را در کنترل نشست‌­های قائم و جابه‌جایی­‌های افقی ناشی از حفاری تونل داشته ­است. هم­چنین دیوار با فاصله0/7D از محور تونل و طول نفوذ 0/5D یا C+1D می‌­تواند دیوار دیافراگمی ‌بهینه در این پروژه باشد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Numerical Study of using Diaphragm Wall to Mitigate Mechanized Tunneling Induced Settlements

نویسندگان [English]

  • Mojtaba Shirzehhagh 1
  • Mohammad Oliaei 2
1 Tarbiat Modares University, Tehran, Iran
2 Faculty of Civil and Environmental Engineering, Tarbiat Modares University, Tehran, Iran.
چکیده [English]

Tunneling-induced displacements could be dangerous for surface structures and urban infrastructure, if not controlled. Accordingly, different techniques are carried out to mitigate tunneling-induced displacements. In this regard, using a diaphragm wall is a practical technique. In this study, the effect of using a diaphragm wall for mitigating the Madrid metro tunneling-induced displacements was investigated. Despite mechanized tunneling of the Madrid metro extension, there is considerable settlement due to a thick layer of made soil ground. In this regard, TBM-EPB tunneling of the Madrid metro tunnel has been modeled step by step and three-dimensional in the finite element code of ABAQUS. The main construction aspects of a TBM are modeled, such as the face pressure, the injection of grout behind the segments, the overcut produced by the gap between the diameters of the cutter-head and the shield. The diaphragm wall is also modeled three-dimensional. For the parametric study, the elastic modulus of the wall, length of the wall, friction between the wall and soil, the distance of the wall from the tunnel axis and density of the wall are assumed to be variable. The results show the elastic modulus of the wall and the distance of the wall from the tunnel axis are the most effective parameters in mitigating the tunneling induced surface settlements and horizontal displacements. In the distance of 0.7D between the wall and tunnel axis, a wall of 0.5D or C+1D length could be the optimum option to mitigate the settlements. 

کلیدواژه‌ها [English]

  • Mechanized Tunneling
  • Diaphragm Wall
  • Settlements
  • TBM
  • Numerical modeling
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