بررسي آزمايشگاهي رفتار لرزه‌يي ديوار هاي خاك مسلح سگمنتال با جوشن فلزي

Experimental study of seismic behavior of segmental reinforced soil walls with steel strip

بررسي ادبيات فني موجود در زمينه‌ي ديوارهاي خاك مسلح، نشان‌دهنده‌ي آن است كه رفتار لرزه‌يي اين نوع سازه‌هاي نگهبان تاكنون از منظر سختي و ميرايي مورد بررسي قرار نگرفته است. لذا در اين پژوهش با ساخت 6 مدل آزمايشگاهي g1 به مقياس 1 به 10 و اعمال شتاب پايه‌ي سينوسي با دامنه‌ي g1/0 تا g8/0 و بسامدهاي5 و 8 هرتز، مقادير كرنش در تسمه‌هاي فلزي و شتاب جسم خاك و همچنين نشست سطح مدل پايش شد. با تحليل نتايج به‌دست‌آمده در آزمايش‌هاي يادشده، مكانيزم‌هاي مختلف گسيختگي اين نوع ديوار به‌همراه مقادير مدول برشي و ميرايي در بسامد 5 هرتز استخراج و با بررسي روابط رگرسيون مختلف در نهايت يك رابطه‌ي نمايي براي مدول برشي و ميرايي بر حسب چيدمان طول مسلح‌كننده‌ها ارايه شده است. در بخش پاياني نوشتار، با مقايسه‌ي بيشينه و ميانگين مقادير نيرو در تسمه‌هاي فلزي با مقادير طراحي، ضريب اطمينان واقعي اين تسمه‌ها تعيين و با مقادير آيين‌نامه‌يي مقايسه شده است.

Due to developing the construction of mechanically stabilized earth walls (MSEW) near to the main transportation lines as well as inter-city routes, investigating the seismic stability of these structures has considerable importance. Reinforced soil walls can be considered of the flexible wall the characteristics aforementioned in earthquake condition cause to a significant depreciation of seismic energy. Flexibility of the structures is Affected by interaction between metal strip, soil and concrete wall facing. Technical literature in this field indicates This structure has not been studied about stiffness and damping. For this purpose in this research with building six 1g laboratory models, Reinforced soil wall to a scale of 1 to 10 consist of two types of soil, sand and composition of sand and clay with different lengths of steel strip and segmental concrete facing seismic behavior of these walls studied. To simulate the seismic acceleration we use the sinus wave with acceleration range of 0.1 g to 0.8g and Frequency of 5 and 8 Hz for the model. In these models studied strain values on the strip ,and acceleration the layers of soil, acceleration the concrete facing. Analyzing the results of the tests the various failure mechanisms with this type of wall ,shear modulus and damping values are obtained at different frequencies. AS results of visual inspection of the models, during the applying all of input motions especially in the worst case, none of the failure modes didnʹt observed in any MSE walls components but the walls movements were appeared in the form of partial sliding and minor bulging. Finally Using the regression , relationships presented for shear modulus and damping in terms of Reinforced lengths .The final article compares the maximum and average values of the force in strip with Design factor of safety offer the real values and compared with the values of the regulations.