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Register a new user3D Numerical Analysis Of A Shallow Tunnel Face Reinforced By Longitudinal Pipes
دراسة عددية ثلاثية الأبعاد لجبهة حفر نفق سطحي مدعمة بالأنابيب الطولية
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Tishreen University ورقة بحثية
Publication date
2018
fields
Geotechnical Engineering
and research's language is
العربية
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Shamra Editor
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يعد استخدام تقنية أنابيب الألياف الزجاجية (Fiber glass pipes) في تدعيم جبهة حفر الأنفاق من الطرق الفعالة جداً للحفاظ على استقرار جبهة الحفر, و بالتالي تخفيض هبوطات سطح الأرض و تشوهات جبهة الحفر و الحفاظ على سلامة العمال و الأليات المستخدمة في الحفر. يقدم هذا البحث نتائج تحليل عددي بطريقة الفروقات المحدودة (برنامج FLAC3D) لسلوك جبهة حفر نفق سطحي مدعم بالأنابيب الطولية الزجاجية, حيث تم وضع موديل عددي ثلاثي الأبعاد و معايرته لبيان فعالية هذه التقنية و إجراء دراسة بارامترية لتحديد بارامترات التقنية الحدية (كثافة (عدد) الأنابيب (A) و طولها (L)). أظهرت النتائج أن تقنية التدعيم باستخدام الأنابيب الزجاجية تخفض الانتقالات (انتفاخ جبهة الحفر و هبوط سطح الأرض) بشكل واضح مما يزيد من استقرار الجبهة, و أن هذه الانتقالات تقل بزيادة طول الأنابيب و بزيادة كثافة الأنابيب المزروعة في جبهة الحفر حتى الوصول إلى الكثافة الحدية, و عند الوصول إلى الطول الحدي يجب تجديد الأنابيب للحفاظ على استقرار عملية الحفر.
Supporting tunnel face by Fiber glass pipes technology is an effective method to maintain the stability of tunnel face, thus reducing surface settlements, face deformation and maintaining the safety of the workers and the mechanisms used in tunneling. This paper presents the results of finite-difference numerical analyses (FLAC3D program) on the behavior of a shallow tunnel face reinforced by longitudinal fiber glass pipes. A 3D numerical model has been calibrated and used to demonstrate the effectiveness of this technique, and perform a parametric study to determine the critical reinforcements parameters (the density (number of pipes)(A) and length (L)). The results indicate that the face reinforcement technique using longitudinal fiber glass pipes can significantly reduce the movements (face displacement and surface settlements), and thus improving the face stability. These movements decrease by increasing the length of the pipes and increasing the density of the pipes until reaching the critical density, and when we reach the critical length, the pipes must be renewed to maintain the stability of the tunneling process.
References used
Atkinson,J.H., Potts,D.M. Subsidence above shallow tunnels in soft ground. Jnl. Geotech. Eng. Div., ASCE, GT4,PP. (1977), 307-325
LUNARDI, P. The influence of the rigidity of the advance core on the safety of tunnel excavation. Gallerie e grandi opere sotterranee, 52, (1997)
GALLI,G; G RIMALDI, A; LEONARDI, A .Three-dimensional modeling of tunnel excavation and lining . Computers and Geotechnics 31 (2004)
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This research study aims at investigating the potential benefits of using the reinforcement
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implement this objective, many numerical 2D-analyses by finite elemen
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program were performed to study the behavior of reinforced soil foundation. And then we
carry out a parametric study of the most effective parameter on bearing capacity. The
results showed that the inclusion of reinforcement can significantly improve the bearing
capacity and reduce the footing settlement. The strain developed along the reinforcement is
directly related to the settlement. The results also showed that the inclusion of
reinforcement can redistribute the applied load to a wider area, thus minimizing stress
concentration and achieving a more uniform stress distribution. The redistribution of
stresses below the reinforced zone can result in reducing the settlement of the underlying
weak clayey soil.
This research study aims at investigating the potential benefits of using the
reinforcement to improve the bearing capacity and reduce the settlement of strip footing on
clay. To implement this objective, many numerical 2D-analyses by finite elemen
t method /
Plaxis program were performed to study the behavior of reinforced soil foundation. And
then we carry out a parametric study of the most effective parameter on bearing capacity.
The results showed that the inclusion of reinforcement can significantly improve the soil’s
bearing capacity and reduce the footing settlement. The strain developed along the
reinforcement is directly related to the settlement. The results also showed that the
inclusion of reinforcement can redistribute the applied load to a wider area, thus
minimizing stress concentration and achieving a more uniform stress distribution. The
redistribution of stresses below the reinforced zone can result in reducing the settlement of
the underlying weak clayey soil.
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