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Numerical Study of Sand Slope Stability Loaded on its Surface and Supported by Piles

دراسة عددية لثبات المنحدرات الرملية المحملة على سطحها و المدعمة بالأوتاد

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 Publication date 2018
and research's language is العربية
 Created by Shamra Editor




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The problem of slope stability is considered as a main geotechnical problem due to the significant damage (material or moral) related to failure. This paper aims to study the influence of piles on the stability of slopes loaded with strip footing and investigating the parameters affected on stability (location of pile row relative to the slope crest X , piles spacing S , piles length L and edge distance of the footing b ). This study has been realized in two phases : the first phase consists in establishing a numerical model for sand slope by using finite element analyses program (FLAC3D) and determining the footing settlement at crest of slope before using piles and after reinforcing , after that the numerical results is compared with the experimental ones (reference case ). A close agreement between experimental and numerical curves is noticed .The second phase deals with studying the influence of most important parameters such as ( piles length ,piles spacing, pile row location relative to the slope crest on stability and edge distance of the footing) on the slope stability. The results of parametric study have shown the piles installed near the slope crest is more efficient in reinforcing where the safety factor is increased by reducing the distance between row of piles and slope crest and the greatest value for safety factor when X=0.7Lx . The currently study showed the efficiency of piles to increase the ultimate bearing capacity with increasing edge, after that at b=3B the increase in ultimate bearing capacity decreased. Also the slope stability depends significantly on pile length and it increases even reaching the length equals the height of the slope. At other hand, the safety factor is reduced by increasing the piles spacing, so that the efficiency of pile is disappeared when pile spacing equals to six times pile diameter(UBCR<1.1).


Artificial intelligence review:
Research summary
تتناول هذه الدراسة مشكلة استقرار المنحدرات الرملية المحملة على سطحها والمدعمة بالأوتاد، وهي مشكلة جيوتكنيكية هامة نظراً للأضرار الكبيرة المرتبطة بانهيار المنحدرات. يهدف البحث إلى دراسة تأثير الأوتاد على استقرار المنحدر المحمل بحمولة أساس شريطي على سطحه، ودراسة العوامل المؤثرة على الاستقرار مثل البعد عن قمة المنحدر، التباعد بين الأوتاد، طول الوتد، وبعد طرف الأساس الشريطي عن قمة المنحدر. تم إنجاز البحث على مرحلتين: الأولى تضمنت تشكيل نموذج عددي لمنحدر رملي باستخدام برنامج FLAC وحساب هبوط الأساس قبل وبعد التدعيم بالأوتاد، ومقارنة النتائج مع نتائج مخبرية مرجعية. أما المرحلة الثانية فتناولت دراسة بارامترية لأهم العوامل المؤثرة على استقرار المنحدر المدعم. أظهرت النتائج أن تنفيذ الأوتاد بالقرب من قمة المنحدر أكثر فعالية في التدعيم، وأن استقرار المنحدر يعتمد بشكل ملحوظ على طول الوتد والتباعد بين الأوتاد. كما أظهرت الدراسة فعالية الأوتاد في زيادة قدرة التحمل الحدية مع زيادة بعد الحمولة عن طرف المنحدر.
Critical review
دراسة نقدية: تعتبر هذه الدراسة مهمة في مجال الهندسة الجيوتكنيكية، حيث تقدم حلولاً عملية لمشكلة استقرار المنحدرات الرملية. ومع ذلك، يمكن توجيه بعض النقد البناء للدراسة. أولاً، الدراسة تعتمد بشكل كبير على النمذجة العددية باستخدام برنامج FLAC، والذي رغم فعاليته، قد لا يعكس تماماً الظروف الواقعية للتربة والمنحدرات. ثانياً، لم تتناول الدراسة تأثير العوامل البيئية مثل الأمطار والزلازل بشكل كافٍ، وهي عوامل قد تؤثر بشكل كبير على استقرار المنحدرات. ثالثاً، الدراسة تركزت على نوع واحد من التربة (الرملية)، وبالتالي قد تكون النتائج غير قابلة للتعميم على أنواع أخرى من التربة. أخيراً، كان من المفيد تضمين دراسات حالة من مواقع فعلية لتأكيد النتائج العددية والمخبرية.
Questions related to the research
  1. ما هي العوامل الرئيسية التي تمت دراستها في هذه البحث لتحديد استقرار المنحدرات الرملية؟

    العوامل الرئيسية التي تمت دراستها هي البعد عن قمة المنحدر (X)، التباعد بين الأوتاد (S)، طول الوتد (L)، وبعد طرف الأساس الشريطي عن قمة المنحدر (b).

  2. ما هو البرنامج الذي استخدم في النمذجة العددية لهذه الدراسة؟

    استخدم برنامج FLAC في النمذجة العددية لهذه الدراسة.

  3. ما هي النتيجة الرئيسية المتعلقة بتأثير طول الوتد على استقرار المنحدر؟

    النتيجة الرئيسية هي أن استقرار المنحدر يزداد بزيادة طول الوتد حتى الوصول إلى طول حدي يساوي ارتفاع المنحدر.

  4. كيف يؤثر التباعد بين الأوتاد على استقرار المنحدر وفقاً للدراسة؟

    يؤدي زيادة التباعد بين الأوتاد إلى انخفاض عامل الاستقرار، حيث يبدأ تأثير الأوتاد بالتلاشي تقريباً عند زيادة التباعد عن ستة أضعاف قطر الوتد.


References used
Abdelaziz.A , Hafez.D , Hussien.A , The effect of pile parameters on the factor of safety of piled –slopes using 3D numerical analysis.J ,HBRC Journal.(2015)
Ashour.M, Ardalan.H, Analysis of piled stabilized slopes based on soil-pile interaction, Journal of Computer and Geotechnics,39 (2012);85-97
Cheng Y.M ,Wei WB, Strength reduction analysis for slope reinforced with one row of piles, Computer and Geotechnics 36 (2009); 1176–1185
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