معرفی دو اصلاح مؤثر برای بهبود پیش‌بینی رفتار دینامیکی خاک‌های دانه‌ای در مدل رفتاری پاستور- زینکوویچ

نوع مقاله : پژوهشی

نویسنده

• امین ایرجی

ارومیه

10.22067/civil.v32i1.63664

چکیده

دو اصلاح مؤثر برای بهبود پیش­بینی رفتار دینامیکی خاک‌های دانه­ای توسط مدل رفتاری خمیری تعمیم­یافته(Generalized plasticity)  پاستور- زینکوویچ (Pastor-Zienkiewicz, PZ) معرفی شده‌است. اصلاح اول برای در نظر گرفتن پدیدۀ اثر سست­شوندگی در بارگذاری متناوب خاک‌های دانه­ای متراکم و اصلاح دوم برای بهبود پیش­بینی پدیدۀ رچتینگ (Ratcheting) یعنی کرنش‌های خمیری پیش­رونده در خاک‌های دانه­ای تحت بارگذاری متناوب اعمال شده‌است. از سه آزمایش سه­محوری و سه آزمایش کرنش مسطح تحت بارگذاری متناوب برای صحت­سنجی مدل اصلاح­شده استفاده شده‌است. در هر دو اصلاح مذکور، پیش­بینی تغییرات تنش در مقابل کرنش و هم‌چنین تغییرات کرنش حجمی رضایت‌بخش بوده­اند؛ با این حال نتایج پیش­بینی تغییرات کرنش حجمی در اصلاح دوم نسبت به اصلاح اول تطابق بیشتری با آزمایش‌ها داشتند.
 

کلیدواژه‌ها

• نظریه خمیری تعمیم یافته
• اصلاح مدل رفتاری
• خاکهای دانه ای متراکم
• شبیه سازی بارگذاری متناوب
• سست شوندگی
• رچتینگ

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عنوان مقاله [English]

Introducing Two Effective Modifications for Pastor-Zienkiewicz Model for Improvement of Dynamic Simulation Capability of Granular Soils

نویسنده [English]

• Amin Iraji

Urmia University

چکیده [English]

Two effective modifications were introduced for Pastor-Zienkiewicz (PZ) model to improve the prediction of dynamic behavior of granular soils. The first modification was implementation of degradation effect for dense granular soils under cyclic loading, and the second was improvement of ratcheting effect for granular soils under cyclic loading. Three cyclic triaxial tests and three cyclic plane strain test were used to validate the introduced modifications. Predictions of stress versus strain for both of modifications were satisfactory. However, predictions of volumetric strain for the second modification were better than those of the first modification.

کلیدواژه‌ها [English]

• Generalized plasticity theory
• modification of constitutive law
• dense granular soils
• simulation of cyclic loading
• degradation
• Ratcheting

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