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Register a new userAnalysis the Effect of soil permeability on stability of the upstream shell of the dam under rapid drawdown(Braddon dam)
تحليل تأثير نفاذية التربة المكونة لوجه السد الأمامي على استقراره في ظروف التفريغ السريع لبحيرته (حالة سد برادون)
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يتأثر استقرار الوجه المبلل في السدود بشكل كبير تحت تأثير التفريغ السريع لبحيراتها و ذلك بسبب ضغط الماء المسامي الذي يأخذ قيماً تتعلق بنفاذية الترب المكونة للمنحدر, نقدم في هذه الورقة دراسة استقرار الوجه المبلل تحت تأثير التفريغ السريع لسد برادون الواقع في محافظة اللاذقية. تم افتراض أنواع من الترب المكونة للمنحدر الأمامي و تحليل استقرار كل نوع تحت تأثير برنامجي تفريغ, في البرنامج الأول يتم التفريغ بحسب غزارة مأخذ الري البالغة 25m3/s و في البرنامج الثاني يتم التفريغ بحسب غزارة نفق تحويل المجرى النهري البالغة 500m3/s. أظهرت نتائج تحليل استقرار المنحدر الأمامي في الشروط الطرفية المحددة على عدة أنواع الترب المدروسة وجود بعض الترب التي تؤمن عامل استقرار مقبول و بعض الترب التي تسبب انهياراً للمنحدر الأمامي. بذلك نستطيع أثناء مرحلة الدراسة التحكم بنوع المادة المكونة للمنحدر الأمامي, و اختيار التربة التي لا تسبب خطورة على استقراره في ظروف التفريغ السريع, كما تبين أن القيم الكبيرة لعوامل الأمان تعطيها المنحدرات المكونة من ترب عالية النفاذية و من الترب قريبة التكوين لتربة النواة نفسها. أما في الترب الواقعة بين الحالتين السابقتين فتظهر انخفاضاً في قيم عامل الاستقرار.
The stability of the upstream shell of the dams is changed under the rapid drawdown condition where the pore water pressure has a different values according to the soil permeability. This paper considers the stability of the upstream shell of the "Braddon" dam with many types of soil and analyses each type under two rapid drawdown programs, the first program is when the discharge happens, according to the irrigation outlet by 25 m3/s, and the second program is when the discharge happens according to the tunnel conversion of the river by 500 m3/s. The obtained results show, that the stability of the upper slope under considered boundary conditions changed according to the soil type. Some soil have good stability factor while other soil collapsed .Accordingly, we can conclude that the type of soil of the upper dam slope is important and we could chose the appropriate type which does not cause dangerous during the rapid drawdown. Also the study shows that: the highest values of the safety factors result when the slopes are formed of high permeability soils as well as the slopes of homogeneous soil, while the soils formed of materials between them appeared decreasing values of safety factors.
References used
ALONSO,E;PINYOL,N,Slope stability under rapid drawdown conditions, UniversitatPolitècnica de Catalunya, Barcelona,Canada2003,367
FREDLUND,M.Combined Seepage and Slope Stability Analysis of RapidDrawdown Scenarios for Levee Design.Geo-Frontiers2011© ASCE ,2011,1595- 1604
TRAN,T.stability problems of an earthfill dam in rapid drawdown condition.SlovakRepublicGrant Project No. 1/9066/02, 2004
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0.25H to
1V:2.0H, and also present the effect of the varied thickness on slope stability for both
upstream and downstream under three design conditions i.e. during and end of
construction, steady state seepage and rapid draw down by General Limit Equilibrium
Method using GeoStudio software.
It was observed from the analysis that by varying the thickness of vertical core of
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thickness of core tends to sharp decline in factor of safety for both upstream and
downstream slope under different design conditions.
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In this paper, we focus on the importance of conducting the necessary tests either
field or laboratory in order to obtain realistic values for soil hydrodynamic parameters
allowing the best result to simulate the actual situation of any engineering
facility.
The importance of this research highlights in earth dams and dikes which have great
importance to economic, environmental and human. It is necessary to be complete
accuracy when creating a mathematical model to study stability of these structures. From
here comes the need to calculate these parameters rather than extracted from engineering
codes, that we will use them to simulate the effect of long rainfall on the distribution of
water content in the Hweez dam soil and hence its stability. We will build a mathematical
model for dam using PCSiWaPro® depending on transition flow chart. concerning that,
hydraulic conductivity and volumetric water content in the soil are functions of pore water
pressure. These equations with their functions give a smooth transition of the studied
model where the saturated state is considered as a special case of the used equations.
The aim of this research is to predict the quantities of soil lost by the water erosion in the
Al-Hawiz Dam basin area using GIS and RUSL. R factor was calculated through
matimatical equation after collecting rain data during 2008-2017 from weather
station at
Basel-Al-Assad airport .k value of each soil sampl was calculated after determination of
txture,structure,saturated hydrolic conductivity, and organic matter).a map were prepared
showed local distribution of k values .slop factor was determined as well as using DEM for
studied region, and slop map was introduced in mathematical equation through a GIS to
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of soil lost quantitis ,maps of LS,C,K was multiplicated with R value.
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very low risk ,low,medium,high .The results of soil lost quantities were classified in to 4
classes in studied region : very low( 0-5) t/h/year,low( 5-12 ) t/h/year and medium ( 12-24
t/h/year and severe in which soil loss exceeded 24 t/h/year
This research includes analytical study by Finite Element Method about the effect of
earthquakes in the stability of ALBASEL DAM, so we have set a numerical model suitable
by using programs Slope/W, Quake/W. We run the model and we got the results
of the
simulation, which summarized in calculation factors of safety for verification the final
stability of the dam under the effect of different intensity earthquakes. And then were
compared between the two cases static and dynamic model showing the effect of the shear
variables of the soil angle of internal friction and tendency of slops dam and the different
situations of the lake water levels and the high of dam in addition to the effect of the
construction material of the dam on the stability of the body of the dam.
After the study each case depending on the parameters, that are entered, and based
on the resulting factors of safety, the diagrams are painted to appear the positive or the
negative effects to increase or decrease any variable of the dam variables in each of the
static case and the dynamic case. And then we studied the effect of seismic Amplification
resulting from the body of the dam on both the two horizontal and vertical component of
seismic acceleration. The results will help us in a perfect choice for variables of
Embankment dams for design.
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