بررسی ظرفیت روانگرایی در تونل‌ها - مطالعه موردی: قطعه شرقی- غربی‌تونل خط هفت متروی تهران

نوع مقاله: مقاله پژوهشی

نویسندگان

1 کارشناس ژئوتکنیک/موسسه مهندسین مشاور طاها-قرارگاه خانم

2 موسسه مهندسین مشاور طاها-قرارگاه سازندگی خاتم الانبیا

3 شرکت آب منطقه ای استان البرز

چکیده

روانگرایی یکی از پیچیده‌ترین و مخرب‌ترین پدیده‌هایی است که حین زلزله اتفاق افتاده و سبب آسیب و یا تخریب سازه‌های مختلف می شود. نهشته‌های دانه‌ای سست و اشباع در مناطق زلزله‌خیز، مستعد این پدیده هستند هر چند پدیده روانگرایی و تأثیر آن بر سازه­های سطحی به کرات مورد مطالعه قرار گرفته، اما تأثیر آن بر سازه­های زیرزمینی کمتر مورد توجه بوده است. همچنین با توجه به گسترش فضاهای زیر زمینی مانند مترو و تونل­های ماشین­رو در کشورهای رو به توسعه مانند ایران و قرار گرفتن کشور در منطقه­ای با لرزه­خیزی بالا ضرورت مطالعه در این زمینه آشکار می­شود. در این پژوهش پتانسیل روانگرایی در قطعه شرقی- غربی‌خط 7 متروی تهران مورد ارزیابی‌ قرار گرفته است. به منظور سهولت در بررسی‌ها این قطعه از تونل به 6 بخش تقسیم شده است و هر بخش بطور مجزا مورد ارزیابی‌قرار گرفته است. در این پژوهش از سه روش که بر پایه عدد SPT هستند استفاده شده است که عبارتند از روش سید، روش جدید ونکوور و روش متوسط که میانگینی از چند روش ارزیابی است. سپس پتانسیل روانگرایی بر پایه سرعت امواج برشی در خاک مورد ارزیابی قرار گرفته است و در نهایت یک مقطع از تونل با استفاده از نرم افزار المان محدود Plaxis  مدلسازی و تحلیل شده است. در پایان مقادیر بدست آمده از این روش‌ها با هم مقایسه شده است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Study of Liquefaction Potential in Urban Tunnels - A Case Study: East-West Part of Line 7 of Tehran Subway

نویسندگان [English]

  • masoud ahmadvand 1
  • amirhosein monajemi 2
  • hamed ghadami 3
1 Geotechnic MSc/taha consulting engineers Co.
2 taha consultant engineering
3 alborz regional water Co.
چکیده [English]

The liquefaction is one of the most complicated and destructive phenomena that occurs during earthquake and causes failure and destruction in various structures. Granular and saturated sediments in seismic hazard zones are susceptible to this phenomenon. Although liquefaction and its effects on surficial structures have been extensively studied, relatively less attention has been paid to its effects on subsurface structures. Moreover, due to recent developments in subsurface structures such as subway and traffic tunnels in seismic hazard zones of developing countries such as Iran, the investigation of liquefaction effects on subsurface structures is of great importance.
 
Summary
In this paper, liquefaction potential of east-west part of line 7 of Tehran subway has been investigated. For the ease of this investigation, this part of tunnel has been divided into six parts, each of which has separately been evaluated. Liquefaction potential has been evaluated based on shear wave speed and finite element modeling software called PLAXIS. Finally, the obtained results from various methods have been compared.
 
Introduction
Liquefaction and its effects on surficial structures have been extensively investigated. However, relatively less attention has been paid to its effects on subsurface structures. In addition, considering the construction of subsurface structures such as subway and traffic tunnels in seismic hazard zones, the investigation of liquefaction effects on subsurface structures appears to be significant.
 
Methodology and Approaches
In this paper, liquefaction potential of east-west part of line 7 of Tehran subway has been investigated. Due to the ease of investigations, this part of the tunnel has been divided into six parts, each of which has separately been evaluated. In this evaluation, three types of analytical methods, including the seed method, the novel method of Vancouver, and the Intermediate method which is the average of several conventional methods have been employed. Then, liquefaction potential has been evaluated based on shear wave speed in soil. Finally, a section of tunnel has been modeled and investigated using the finite element modeling software called PLAXIS.
 
Results and Conclusions
After obtaining the results of various methods, these results have been compared. The results of finite element method are in good agreement with the results of analytical methods used in this study.

کلیدواژه‌ها [English]

  • Liquefaction
  • Tunnel
  • Standard penetration number
  • Seismic
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