scholarly journals Determination of Stability During First Impounding in Jatigede Earth Dam

2019 ◽  
Vol 3 (2) ◽  
pp. 1
Author(s):  
Anafi Minmahddun ◽  
Teuku Faisal Fathani ◽  
Fikri Faris
Keyword(s):  
Safety Factor ◽  
Limit Equilibrium ◽  
Pressure Change ◽  
Earth Dam ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Seepage Analysis ◽  
Factors Affecting ◽  
Upstream Slope ◽  
Dam Stability

The Jatigede Dam is a multi-purpose rockfill dam located in Sumedang Regency,West Java Province. The construction of the Jatigede Dam started in 2008 and it isthe second largest dam in Indonesia after the Jatiluhur Dam. As one of the vital facilities, it is highly necessary to evaluate the stability of the Jatigede Dam to avoid dam collapse. First reservoir filling is one of the factors affecting the dam stability; therefore, this research aims to evaluate the Jatigede Dam stability during impounding. The transient seepage analysis was conducted to evaluate the pore pressure change during impounding. The result of seepage analysis was used to analyze the dam stability using the limit equilibrium method with Rockscience software of Slide2. The results of the seepage analysis shows that the rise of the reservoir water level affects the upstream slope stability. The safety factor of the upstream slope changes during the impounding process. All thesafety factors for the upstream and downstream slopes during impounding still meet theminimum safety factor criteria required. 

scholarly journals Experimental and numerical study of upstream slope stability in an earth dam reservoir under rapid drawdown conditions

2020 ◽  
Vol 8 (1) ◽  
pp. 1-15
Author(s):  
Seyed Habib Mousavi Jahromi ◽  
Mansour Pakmanesh ◽  
Amir Khosrojerdi ◽  
Hossein Hassanpour Darvishi ◽  
Hossein Babazadeh
Keyword(s):  
Water Level ◽  
Pore Water Pressure ◽  
Numerical Study ◽  
Water Pressure ◽  
Earth Dam ◽  
Dam Reservoir ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Seepage Analysis ◽  
Upstream Slope

The rapid ‎drawdown of the dam reservoir is one of the most common situations occurring in the lifetime of a dam. For this reason, one of the main factors in the design of the upstream slope is the rapid drainage of the reservoir. In this case, the upstream slope is in a critical condition and the slope may be unstable. When the water surface in the reservoir is drawdown suddenly, the water level in the dam body does not decrease at the same time as the reservoir water level. The analysis of seepage from the earth dam body and calculation of the water loss play an important role in calculating the amount of pore water pressure, and, consequently, the stability analysis of the dam body. In addition, any seepage analysis is dependent on the hydraulic properties of the dam materials. In order to investigate the effect of hydraulic conductivity on the rapid drawdown of water level and the seepage, an experimental model was constructed of an earth dam. By accurate measurement of hydraulic parameters of the materials in saturated and unsaturated media, the flow through this model was modeled using a disk penetrometer by seep/w software. The results were then compared with the observed data.

scholarly journals Unsteady Seepage Behavior of an Earthfill Dam During Drought-Flood Cycles

Geosciences ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 17 ◽  
Author(s):  
Ziyang Li ◽  
Wei Ye ◽  
Miroslav Marence ◽  
Jeremy Bricker
Keyword(s):  
Pressure Gradient ◽  
Water Level ◽  
Pore Pressure ◽  
Internal Erosion ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Upstream Slope ◽  
Earthfill Dams ◽  
The Stability ◽  
Pore Pressure Gradient

Climate change with extreme hydrological conditions, such as drought and flood, bring new challenges to seepage behavior and the stability of earthfill dams. Taking a drought-stricken earthfill dam of China as an example, the influence of drought-flood cycles on dam seepage behavior is analyzed. This paper includes a clay sample laboratory experiment and an unsteady finite element method seepage simulation of the mentioned dam. Results show that severe drought causes cracks on the surface of the clay soil sample. Long-term drought causes deeper cracks and induces a sharp increase of suction pressure, indicating that the cracks would become channels for rain infiltration into the dam during subsequent rainfall, increasing the potential for internal erosion and decreasing dam stability. Measures to prevent infiltration on the dam slope surface are investigated, for the prevention of deep crack formation during long lasting droughts. Unsteady seepage indicators including instantaneous phreatic lines, equipotential lines and pore pressure gradient in the dam, are calculated and analyzed under two assumed conditions with different reservoir water level fluctuations. Results show that when the water level changes rapidly, the phreatic line is curved and constantly changing. As water level rises, equipotential lines shift upstream, and the pore pressure gradient in the dam’s main body is larger than that of steady seepage. Furthermore, the faster the water level rises, the larger the pore pressure gradient is. This may cause internal erosion. Furthermore, the case of a cracked upstream slope is modelled via an equivalent permeability coefficient, which shows that the pore pressure gradient in the zone beneath the cracks increases by 5.9% at the maximum water level; this could exacerbate internal erosion. In addition, results are in agreement with prior literature that rapid drawdown of the reservoir water level is detrimental to the stability of the upstream slope based on embankment slope stability as calculated by the Simplified Bishop Method. It is concluded that fluctuations of reservoir water level should be strictly controlled during drought-flood cycles; both the drawdown rate and the fill rate must be regulated to avoid the internal erosion of earthfill dams.

Deformation and stability analyses of a near-dam rocky slope and its potential landslide-generated wave threats

2021 ◽  
pp. qjegh2021-018
Author(s):  
Ming-liang Chen ◽  
Xing-guo Yang ◽  
Shun-chao Qi ◽  
Hai-bo Li ◽  
Jia-wen Zhou
Keyword(s):  
Water Level ◽  
Rock Slope ◽  
Limit Equilibrium ◽  
Water Levels ◽  
Reservoir Rock ◽  
Water Diversion ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
The Impact

Occurrence of a reservoir landslide and its potential secondary hazards near a dam can result in significant losses and casualties, such as those that resulted from the Vajont landslide. In this study, a cataclinal rock slope in the Maoergai reservoir was taken as a case to study the characteristics of the gravitational deformation process and to analyze the potential threat. The stability of rock slope is analyzed by the limit equilibrium method, and the potential landslide movement and subsequent waves are also simulated. Results indicate that lithology, geological structure, reservoir water level changes and artificial activities all play an important role for the large deformation of rock slope deformation, which is characterized by a combination of bending-toppling and principally shear-slip. Pre-calculations of potential threats indicated that the impact of a landslide wave would be greater at dead water levels than at the normal water level and could result in blockage of the inlet to the water diversion structure on the opposite right bank. These findings provide implication for the control of reservoir rock slopes: (i) serious attention should be paid to the influence of water on rock strength in early and (ii) infiltration must be prevented during water level rise.Thematic collection: This article is part of the Role of water in destabilizing slopes collection available at: https://www.lyellcollection.org/cc/Role-of-water-in-destabilizing-slopes

Study on the Grouting Reinforcement and Stability of a Tailings Initial Dam

2012 ◽  
Vol 602-604 ◽  
pp. 1570-1573
Author(s):  
Guang Jin Wang ◽  
Xiang Yun Kong ◽  
Qiang Liang ◽  
Yue Tong Si
Keyword(s):  
Poor Quality ◽  
Disaster Prevention ◽  
Prevention Measures ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Research Results ◽  
Grouting Pressure ◽  
The Poor ◽  
Grouting Reinforcement ◽  
Dam Stability

The safety operation of tailings initial dam is the necessary conditions to ensure that the tailings dam is steady. In view of the poor construction quality and the appearing of jet shape seepage with the tailings leak in a tailings initial dam, the thesis analyzed the dam composite of tailings initial dam, the study of dam stability was carried out in the different working conditions and the disaster prevention measures was discussed. The research results indicated that the cementation was better and the strength of rock-soil body was higher in the upper dam body of tailings initial dam. However, the gravel cementation was weaker and strength of rock mass was relatively lower in the bottom dam body of that. Based on the poor quality of construction and penetrating seepage with the tailings initial dam, it should be feasible to adopt the grouting reinforcement way so as to reinforce the tailings initial dam. But the grouting pressure should be not more than 0.2 MPa. It will rely on increasing the dam self-respect and decreasing reservoir water level in the grouting process to reduce the risk of landslide. The research results can provide the theory basis on the disaster prevention and control of the tailings initial dam.

Stability Analysis of Earth Dam under Unsaturated Seepage

2008 ◽  
Vol 33-37 ◽  
pp. 1129-1134
Author(s):  
Zheng Hua Xiao ◽  
Bo Han ◽  
Akenjiang Tuohuti ◽  
Hong Jian Liao
Keyword(s):  
Stability Analysis ◽  
Unsaturated Soil ◽  
Limit Equilibrium ◽  
Earth Dam ◽  
Hydraulic Pressure ◽  
Earth Dams ◽  
Seepage Analysis ◽  
Unknown Quantity ◽  
The Stability ◽  
Unsaturated Seepage

This paper is mainly concerned with the saturated-unsaturated seepage analysis of earth dams based on unsaturated soil theory and the stability analysis of earth dams based on conception of slices. At first, beginning basic seepage theory, thesis introduce the saturated-unsaturated and steady-unsteady seepage differential equation of porous media and the FEM regarding hydraulic pressure head as basic unknown quantity. Then considering the shear strength of unsaturated soil, the method of analysis of general limit equilibrium has been approved and it can be used in the analysis of the stability of saturated-unsaturated slopes. Through an example it is respectively discussed effects of seepage flow when water head is changed in earth dam and the effects of percolation in the stability of the earth dam slope. Some helpful conclusions are gained. This can be making the best of the tow methods and the results can be used in engineering for reference.

scholarly journals Theoretical and Case Studies of Interval Nonprobabilistic Reliability for Tailing Dam Stability

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Longjun Dong ◽  
Daoyuan Sun ◽  
Xibing Li
Keyword(s):  
Mechanical Parameters ◽  
Analysis Model ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Proposed Model ◽  
Tailing Dam ◽  
Calculation Results ◽  
Tailing Dams ◽  
Dam Stability ◽  
The Stability

The stability of the operation of a tailing dam is affected by reservoir water level, phreatic line, and mechanical parameters of tailings. The values of these factors are not a definite value in different situations. Meanwhile, the existence of the phreatic line makes it a more complex issue to analyze the stability of the tailing dam. Additionally, it is very hard to give a definite limit to the state of tailing dam from security to failure. To consider the uncertainty when calculating the stability of the tailing dams, interval values are used to indicate the physical and mechanical parameters of tailings. An interval nonprobabilistic reliability model of the tailing dam, which can be used when the data is scarce, is developed to evaluate the stability of the tailing dam. The interval nonprobabilistic reliability analysis model of tailing dam is established in two cases, including with and without considering phreatic line conditions. The proposed model was applied to analyze the stability of two tailing dams in China and the calculation results of the interval nonprobabilistic reliability are found to be in agreement with actual situations. Thus, the interval nonprobabilistic reliability is a beneficial complement to the traditional analysis method of random reliability.

Seepage Analysis for Qianjiangping Landslide Applied Three Gorges Reservoir Water Level and Heavy Rainfall

2011 ◽  
Vol 90-93 ◽  
pp. 734-737 ◽  
Author(s):  
Qiang Feng ◽  
Shi Rong Xiao
Keyword(s):  
Water Level ◽  
Three Gorges Reservoir ◽  
Heavy Rainfall ◽  
Three Gorges ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Seepage Analysis ◽  
Qianjiangping Landslide ◽  
Unsaturated Seepage

Saturated and unsaturated seepage analysises are given for the neonatal landslide——Qianjiangping Landslide applied Three Gorges Reservoir water level and rainfall which happened after the first sluice in Three Gorges Reservoir, the conclusions are discussed from the two aspects: Three Gorges Reservoir sluice and heavy rainfall.

Integral Anti-Slide Stability Analysis of RCC Gravity Dam

2013 ◽  
Vol 275-277 ◽  
pp. 1480-1483
Author(s):  
Li Zhang ◽  
Dan Pang ◽  
Jian Liu
Keyword(s):  
Stability Analysis ◽  
Safety Factor ◽  
Limit Equilibrium ◽  
Limit Equilibrium Method ◽  
Gravity Dam ◽  
Safety Factors ◽  
Standard Requirement ◽  
Load Combination ◽  
Dam Stability ◽  
The Stability

The main purpose of the gravity dam stability analysis is to examine the stability safety in all possible load combination cases. Combined with the engineering example, the method of modeling , loading and analysis for the gravity dam by ansys is introduced in this paper, then the limit equilibrium method and the strength reserve method are adopt to calculate the safety factor under two conditions. The results indicate that the two safety factors which are calculated under two conditions can all satisfy the standard requirement; it is reasonable to analyze the gravity dam stability through two methods.

scholarly journals Effect of hydraulic conductivity of unsaturated soil on the earth dam performance

2018 ◽  
Vol 162 ◽  
pp. 01008
Author(s):  
Mohammed Fattah ◽  
Mahmood Ahmed ◽  
Nawar Ali
Keyword(s):  
Hydraulic Conductivity ◽  
Water Level ◽  
Water Levels ◽  
Degree Of Saturation ◽  
Earth Dam ◽  
Core Material ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Partially Saturated ◽  
The Core

In this paper, the finite element method is uzed to solve the governing equations of flow through earth dams. The computer program Geo-Slope is used in the analysis through its sub-program named SEEP/W. A case study is considered to be Al-Adhaim dam which consists of zoned embankment with a total length of 3.1 km. The dam in its actual design is analyzed. Then, an attempt is made to study the seepage in unsaturated zone of the dam through studying the effect of several parameters including the effect of changing the unsaturated hydraulic conductivity with the degree of saturation of the core soil and changing of water level in the reservoir. A procedure is proposed to define the hydraulic conductivity function from the soil water characteristic curve which is measured by the filter paper method. Fitting methods are applied through the program SoilVision. A parametric study was carried out and different parameters were changed to study their effects on the behavior of partially saturated soil. The study reveals that the rate of flow is decreased by about 20 - 27% when the degree of saturation of the core material is decreased from 100% to 50% at water level 115.75 m, while the exit gradient of flow is decreased by about 13 -15%. This decrease in flow rate becomes 13-15% and 8-9.5% when the reservoir water level is 131.5 m and 143.5 m, respectively, while the exit gradient of flow is increased by about 23-29.5% and 29-29.5% when the reservoir water level is 131.5 m and 143.5 m, respectively. When the state of soil changes from fully saturated S= 100% to partially saturated S= 90%, a rapid increase in head gradient and pore water takes place at the embankment base for different water levels in the reservoir. This decrease plateaus out on further decrease in the degree of saturation.

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