تحليل لرزه اي غير خطي سه بعدي سد بتني وزني با نسبت هاي مختلف طول به ارتفاع

مدلسازي عددي سازه هاي بزرگ نظير سدها وسيله اي مناسب براي تحليل لرزه اي و بررسي عملكرد آنها مي باشد. شكل دره از پارامترهاي مهم در انتخاب نوع سد و تعيين كننده نسبت طول به ارتفاع سد است.در تحقيق پيش رو مدل سه بعدي المان محدود سد وزني پاين فلت بدون در نظر گرفتن درزهاي انقطاع به همراه رفتار غير خطي مصالح بدنه سد تهيه شده است. در اين مدلسازي بارگذاري استاتيكي شامل وزن بدنه سد و بار هيدرواستاتيك مخزن پر مي باشد. پس از اين بارگذاري استاتيكي، بارگذاري ديناميكي لرزه اي مدل آغاز مي شود. با توجه به اهميت شكل دره، به بررسي تغييرات عرض دره و پاسخ سد به هر سه مولفه حركت زمين پرداخته شده و اثر تغييرات نسبت عرض دره به ارتفاع سد و همچنين اهميت مولفه عرضي حركت زمين در كنار مولفه هاي افقي و عمودي مورد بررسي قرار مي گيرد. اثرات اندركنشي سد - مخزن – پي در تحليل منظور شده و نهايتا با نتايج مدل دو بعدي مقايسه مي گردد.هدف از تحقيق حاضر، مقايسه پاسخ لرزه اي دوبعدي و سه بعدي سدهاي بتني وزني و لزوم ارائه مدل هاي واقعي تر جهت در نظر گرفتن اثرات مودهاي عرضي مي باشد . اثرات اندركنش سد-مخزن-پي، رفتار غيرخطي بتن و نيز شكل هاي مختلف دره مطالعه شده و تاثير هركدام بر پاسخ غيرخطي و پايداري لرزه اي سدهاي بتني وزني تحت مولفه هاي طولي، قائم و عرضي ركورد زلزله انتخابي بطور جداگانه و نيز همزمان مورد بررسي قرار خواهد گرفت.

One of the most vital, essential human being requirements is water, which it has become increasingly sensitive owing to population growth, the need to develop agriculture and industry, and restriction in water resources. Considering this, the need to store water and to use its potential for generating hydroelectric power, which it can be achievable by constructing dams, will be necessitated. Concrete dams play a significant role in Infrastructure in each country. One important part of dams exiting in the world are made of gravity dams and earthquake seems to be the major threat for them in earthquake-prone areas. Hence, the dam fracture, with much stored water, might have brought many conspicuous threats about in these zones. Also, any structural damage could lead to some negative economic effects. These facts have increased the scholars’ attention to the mechanical behavior of dams during the decades. The Seismic analysis of gravity concrete dams, usually, had been considered in an ideal form by means of 2D Monolith in mechanism design and an earthquake effect coefficient. Lately, the research focus, however, has been more on linear time history analytics and fracture analysis of concrete dams in 3D. The numerical modelisation of huge structures such as dams is a proper tool for Seismic analysis and performance evaluation. The valley shape is one of the important parameters in the selection of the dam structure. This parameter plays a crucial role in both Seismic stimulation and its results. In this paper, a 3D finite element model of Pine-flat gravity dam, without interruption seams with a non-linear behavior of the dam’s material, is considered. . Loading has two stages: static and dynamic. In this modelisation, static loading includes both the weight of dam body and the load of filled Hydrostatic tanks. After static loading, loading of Seismic dynamic is begun. Owing to the importance of valley shape, the changes/ deformations of valley width and the dam response to every three elements of ground is investigated. The impact of the ratio changes of width in dam height, as well as the importance of the transverse component of ground motion, along the vertical and horizontal, has been explored. Interaction effects of dam-reservoir-foundation is considered in the considered analysis and ultimately, the output of which is compared with two dimensional model results. The aim of this study is comparing two and three dimensional seismic response of concrete gravity dams and also necessity of providing more realistic models for considering the effects of cross stream modes. Also, not only are interaction effects of dam-reservoir-foundation, the nonlinear behavior of concrete, studied different Valley shapes, and the effect of them on non-liner response investigated, but also the Seismic stability of gravity concrete dams under longitudinal, vertical and the chosen transverse record earthquake are separate and simultaneously studied. The effects of dam-reservoir-foundation interaction, nonlinear behavior of mass concrete, also different shapes of valley are studied and their effect on nonlinear response and seismic stability of concrete gravity dams are evaluated under two and three-component earthquake records.