بررسی مدل عددی دو بعدی تراوش سد خاکی لاسک

معمولا برای طراحی تراوشی سدهای خاکی یک تحلیل دوبعدی در مقطع ماکزیمم ویا مقطع تیپ سد به جای تحلیل تراوشی سه بعدی انجام میگیرد.در این حالت اثر شکل دره ونیز تغییر خصوصیات مصالح در راستای بعد سوم در نظر گرفته نمیشود.در این مقاله تراوش آب از بدنه و پی سد خاکی لاسک به صورت سه بعدی بکمک نرم افزار seep/3dمورد ارزیابی قرار میگیرد.سپس به منظور تعیین میزان تفاوت ناشی از ساده سازی مسئله نتایج حاصل از تحلیل دو بعدی بکمک نرم افزار seep/w ونیز نتایج بدست آمده از رفتار نگاری از مجموعه ابزار دقیق نصب شده در بدنه و پی سد مقایسه میشوند.نتایج نشان می دهد که نتایج تحلیل های ناپایدار دوبعدی سه بعدی و نتایج بدست آمده از رفتار نگاری از حدود 60 روز پس از الین آبگیری تطابق خوبی با یکدیگر پیدا میکنند. ولی با گذشت حدود 500روز نتایج تحلیل های دوبعدی و سه بعدی به تدریج از یکدیگر دور می شوند.ضمنا مقایسه نتایج حاکی از تطابق نتایج رفتارنگاری ابزار دقیق با نتایج حاصل از تحلیل سه بعدی است.

investigation of 2d numerical model of lask earthen dam seepage

according to the climate of iran and placing in arid and low rainfall zones in the world, the growth of population, and need for supplying drinking and agriculture water, it is necessary to control surface waters, optimal use of water resources, avoid wasting of water, and provide water requirements of the country. therefore, construction of earthfill dams on the route of flowing waters in suitable points is of the choices for achieving the mentioned purposes. on the other hand, the issue of water seepage is considered as an essential issue in earthfill dams that in addition to causing water losses, it also causes hazards in the dam performance. modeling of earthfill dams and performing analysis of seepage within the body of these dams are essentially required for determining the amount of seepage and proposing executive solutions for controlling it. regarding the studies and researches conducted in relation with seepage analysis in earthfill dams, it is observed that because of the presence of difficulties in modeling or the analysis of seepage equation in three-dimensional, the modeling is usually done two-dimensionally and performed in a particular section, which apparently seems to be the most critical section. accordingly, the dam structure is designed by considering the results obtained from the analysis of these two-dimensional models. this assumption is a very good approximation in widespread valleys having uniform cross-section and valleys with uniform materials, and the obtained results will be of appropriate accuracy except for the dam supports. however, in narrow valleys or the valleys that their profile is highly variable as well as the valleys with various material types, because of the complexity of seepage pattern and the lack of a section representing the valley characteristics, such an assumption will be sometimes associated with very high errors, which might be also unacceptable. hence, considering the importance of aforementioned contents in this research, 3d modeling of lasak earth fill dam in that's located in narrowe valley with different sections specifications. and there is a possibility of error in 2d modeling. it idiscussed as a case study. and steady state flow analysis for this dam was performed in 2d and 3d, using seep / w and seep / 3d software. the results show the higher accuracy of the 3d model in the representation of the flow lines as well as the exact amount of pore pressure and total head pressure at different sections of the dam.