2عضو هیئت علمی دانشگاه آزاد اسلامی واحد علوم وتحقیقات تهران
3عضو هیئت علمی دانشگاه آزاد اسلامی واحد علوم و تحقیقات تهران
چکیده
امروزه با توجه به گسترش روز افزون محیط‌های شهری، افزایش تراکم سازه‌های سطحی و کمبود فضای لازم برای حمل و نقل درون شهری، نیاز به اجرای سازه‌های زیرزمینی نظیر تونل و ایستگاه‌های زیرزمینی مترو در محیط‌های شهری بیش از گذشته احساس می‌شود. یکی از عوامل حائز اهمیت در اجرای ایستگاه‌های عمیق مترو در محیط‌های شهری انتخاب روش مناسب حفاری است که تأثیر به سزایی در پایداری فضای اطراف تونل در حین حفاری، نشست‌های سطحی ناشی از حفاری و همچنین پایداری درازمدت محیط حفاری شده (ایستگاه مترو) دارد. در این تحقیق با توجه به خصوصیات ژئوتکنیکی زمین و هندسه ایستگاه مورد بررسی، سه روش رایج در حفاری تونل‌های بزرگ مقطع، شامل روش‌های پیش‌نگهدارنده طاقبتنی، گالری‌هایکناری و آلمانی جهت اجرای ایستگاه‌های زیرزمینی از نظر پایداری فضا، تغییر مکان‌های محیطی تونل و نشست ناشی از فرآیند حفاری مورد ارزیابی و بررسی قرار گرفته است. مدلسازی عددی روش‌های مختلف اجرای این فضا با استفاده از روش اجزای محدود و نرم افزار سه بعدی Plaxis 3D Tunnel انجام شده است. با توجه به نتایج، حداکثر نشست سطح زمین در روش گالری‌هایکناری بوده و حداقل آن مربوط به روش پیش‌نگهدارنده طاق بتنی می‌باشد. همچنین نشست سطح زمین در پایان اجرای طبقه اول ایستگاه در دو روش پیش‌نگهدارنده طاق بتنی و آلمانی مقادیر بسیار نزدیک به هم داشته و امکان استفاده از هر دو روش را در ایستگاه‌های یک طبقه نشان می‌دهد.
Investigation of proper methods for implementing deep underground stations, case study on the x7 station from the line seven of Tehran metro
نویسندگان [English]
saied hejazi1؛ navid ganjian2؛ M. R. mansouri3
1PhD Candidate in Geotechnical Engineering; Department of Civil Engineering, Science and Research, Branch, Islamic Azad University.
2Assistant Professor; Department of Civil Engineering, Science and Research, Branch, Islamic Azad University.
3Assistant Professor; Department of Civil Engineering, Science and Research, Branch, Islamic Azad University.
چکیده [English]
Nowadays, the necessity of implementing the underground structures in the urban areas has been increased due to the continuous increase of the spaces needed for intra-urban transports. The road and metro tunnels are among the underground spaces mostly considered in the cities. As the cities are mainly located on the soft and alluvium grounds, some difficulties associated with implementing underground spaces in these grounds may be arised. The most important difficulties in this regard are the settlement of the ground surface during construction and its effect on the surrounding structures.
Introduction
The construction of large section underground spaces such as metro lines stations is essentially important. One of the factors in this regard that should be considered in the urban areas is to select the method of excavating the spaces. This fact has significant effect on the stability of surrounding tunnel spaces during excavation, surface settlement due to the excavation and long term stability of excavated space (e.g. metro station).
Methodology and Approaches
In this research, three methods including pre-supporting concrete arc, side galleries and German method have been studied and evaluated for implementing the underground stations concerning the stability of space, surface displacement of the tunnel and the settlements due to the excavation. In the other words, this research mainly focuses on the effect of using different excavation methods (with or without supporting structure) on the superficial displacements of the tunnel, settlement of ground surface and other parameters. Then, the proper method is suggested for excavating the considered station. The numerical modeling of different methods for implementing the space has been conducted using finite element method and Plaxis 3D software.
Results and Conclusions
The results obtained in this research indicate that the maximum settlement of the ground surface is seen in the side galleries and its minimum in the pre-supporting arc methods. Moreover, at the end of implementation of the first floor of the station, the settlements of ground surface have been very similar in the concrete arc and German methods. It means that these two methods can be used in the one- floor stations.
کلیدواژه‌ها [English]
Underground Metro Station, Surface Ground Settlement, Pre- Supporting Concrete Arc Method, Side Galleries Method, German Method
مراجع
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