شبيه سازي عددي زمين لغزش بر روي شيب هاي غير صلب بوسيله روش هيدروديناميك ذرات هموار تراكم ناپذير سه مرحله ايي صريح

پديده زمين­ لغزش در درياچه سدها و رودخانه­ ها، و توليد و انتشار امواج حاصل از آن، بعنوان يكي از مسائل مهم و پيچيده در زمينه مهندسي هيدروليك مطرح است. امروزه بسط و گسترش روابط عددي و فرآيند مدل­سازي توانسته تا حدودي به درك منطقي از اين پديده­ ها برسد. در اين مقاله از يك روش لاگرانژي جهت حل معادلات حاكم بر جريان استفاده شده است. در ابتدا روش هيدرودينامكي ذرات هموار تراكم­ناپذير سه مرحله­ايي صريح تعريف مي ­شود. به منظور معتبرسازي روش، از مسئله شكست سد روي بستر خشك و مسئله زمين­ لغزش زير سطحي استفاده شده‌ است. در مسئله اول، رسيدن به ضريب همبستگي 9998/0، متوسط خطاي مطلق 0542/0 و ضريب كارايي مدل نش-ساتكليف 974/0 براي پارامترهاي مورد محاسبه، نشان مي­دهد مدل با دقت مناسبي كاليبره شده است كه حاكي از قابليت بالاي اين روش در شبيه­ سازي جريان­ هاي با سطح آزاد و پديده ­هاي مربوط به امواج مي­ باشد. همچنين از مقايسه نتايج اندازه ­گيري شده با آزمايشگاهي در قسمت شبيه­ سازي زمين­ لغزش زير سطحي، مقادير آماري ضريب همبستگي و جذر ميانگين مربعات خطا بترتيب 95/0 و 0071/0 بدست آمدند كه اين نتايج نشان­ دهنده دقت بالاي مدل در محاسبه نيمرخ سطح آب ناشي از زمين­ لغزش زيرسطحي مي ­باشد. سپس سه سناريو جهت مدل­ سازي زمين ­لغزش طراحي و اجرا گرديد. در اين پژوهش به شي ب­ها و جسم غير صلب، بعنوان يك ماده رئولوژيكي (سيال شبه­پلاستيك) نگريسته شده و تحت سيال غير نيوتني كاريوياسودا در مدل­ سازي وارد شدند. در واقع ذرات خاك بستر شيبدار غير صلب بصورت دانه­ هايي كه با خود مشخصات سيال را حمل مي­ كنند مدل­ سازي شده ­اند. در نهايت نتايج در زمان­ هاي 3/0 و 6/0 ثانيه آورده شده­ و تحليل گرديدند.

The coastal waves caused by landslide in the lake of reservoir dams can threaten the safety of the dam. Therefore, the exact recognition of hydraulic flow due to coastal waves has always been of interest to researchers. So far, extensive laboratory and numerical research has been devoted to it. Also, the phenomenon of landslide in the lake of dams and rivers, and the production and propagation of waves resulting from it, is one of the most important and complex issues in the field of hydraulic engineering. Today, the expansion of numerical relations and the modeling process have somewhat contributed to a rational understanding of these phenomena. In this research, a Lagrangian method is used for solving governing equations. Initially, the hydrodynamic method is defined as an explicit three-step incompressible smoothed particle hydrodynamic. This method, by replacing the fluid with a set of particles, provides an approximate solution to the fluid dynamics equations. In this simulation, there are a series of arbitrary interpolation points that can be assumed to be fluid particles. All variables are calculated by these points and are calculated by an interpolation function. In order to validate the method, the dam break problem on dry bed and the subsurface landslide problem have been used. In the first issue, the correlation coefficient of 0.9998, the mean absolute error of 0.5426 and the efficiency coefficient of the Nash-Sutcliff model 0.974 for the calculated parameters indicate that the model is accurately calibrated, which demonstrates the high capability of this method in simulating free surface fluids and wave-related phenomena. Also, comparing the measured results with the experimental data in the subsurface landslide simulation showed that the correlation and mean square error correlation coefficients were 0.95 and 0.0071 respectively, which indicates the high accuracy of the model in calculating the water surface profile caused by landslide subsurface. The results showed that at times after 2 seconds, numerical waves tended to release more than its experimental state, with a difference between the ranges of 5 to 10 cm. This is due to the turbulence of the free surface of water causing the flow of complexity. For smaller body weights and deeper depths of submergence, these differences will be lower in scope. Then three landslide modeling scenarios were designed and implemented. In this study, slopes and nonrigid bodies were considered as a rheological material (pseudoplastic fluid) and entered into modeling as Carreau Yasuda non-Newtonian fluid. The results were reported at 0.3 and 0.6 seconds, and then they were analyzed.