بررسي رفتار لرزه‌يي ديوارهاي حايل خاكي مسلح‌شده با ژيوسينتتيك‌ها جهت پيشنهاد ضريب شتاب افقي معادل زلزله براي مدل

Evaluation of dynamic behavior of geosynthetic reinforced soil retaining walls to present the earthquake equivalent horizontal acceleration coefficient for the model

با توجه به افزايش استفاده از سيستم‌هاي خاك مسلح ژيوسينتتيكي در مناطق لرزه‌خيز، در اين تحقيق به بررسي رفتار لرزه‌‌يي ديوارهاي حايل قايم خاك مسلح‌شده با ژيوسينتتيك‌ها جهت پيشنهاد ضريب شتاب افقي معادل زلزله براي مدل پرداخته مي‌شود. از آنجا كه روش شبه‌استاتيكي، رويكردي مناسب و ساده براي معادل سازي تحليل هاي ديناميكي شيرواني‌هاي خاكي است؛ در اين تحقيق سعي شده است براي ديوارهاي خاك مسلح، روشي مشابه جهت معادل‌سازي رفتار ديناميكي با درنظرگرفتن يك ضريب شبه‌استاتيكي معادل پيشنهاد شود. به اين منظور با درنظرگرفتن نيروهاي بسيج‌شده در مسلح‌كننده‌ها (مهم‌ترين عامل پايداري گوه‌ي گسيختگي) به‌منزله‌ي مبناي مقايسه، ضريب شتاب افقي معادل زلزله براي مدل ارايه شده است. جهت تحليل حساسيت، تاثير پارامترهاي ارتفاع ديوار، نوع شتاب‌نگاشت، فاصله‌ي عمودي مسلح‌كننده، نوع مسلح‌كننده، و نوع خاك كه مي‌توانند اثر قابل‌توجهي بر تغييرشكل‌ها و نيروها داشته باشند مورد بررسي قرار گرفته است.

Geosynthetics have been proved to be suitable for reinforced soil retaining walls. According to increasing of the usage of the geosynthetic reinforced soil systems in seismic active zones which bear frequent earthquakes, it’s important to study the dynamic behavior of these structures. Hence, in this research, the study on the seismic behavior of the Geosynthetic Reinforced Soil Retaining Walls (GRSRW) has been investigated to present the earthquake equivalent horizontal acceleration coefficient for the model. As long as no force is imposed to the reinforcement, existence of reinforcement in soil retaining wall has no effect, hence using the reinforcement is useful only when the applied forces cause the reinforcement tension and the mobilized tension force can overcome the soil tension weakness. Thus, predicting mobilized forces in geosynthetics during earthquake is very important. Pseudo-static method is a suitable and simple approach to substitute dynamic analyses of slope stability. Therefore, in this research, it’s trying to offer an equivalent pseudo-static coefficient with similar approach for the reinforced soil retaining walls to equalize dynamic behavior. A fundamental requirement to assess conservatism in current design practice and to validate new design approaches is a reliable estimate of the load in reinforcement layers to maintain the stability of the reinforced structure. Based on considering forces in reinforcements (as the most important factor of stability) the earthquake equivalent horizontal acceleration coefficient is proposed. The comprehensive sensitivity analyses have been performed to study the effective parameters on the forces and displacements. The effects of most important parameters such as wall height, maximum acceleration, vertical spacing of reinforcements, types of reinforcements and soils through numerical modeling of the geosynthetic reinforced soil retaining walls (GRSRW) under dynamic loading with finite difference method by using FLAC have been investigated. The findings indicate rather positive results with each parameter.