scholarly journals Effects of material properties on structural behaviour and safety evaluation of an old arch dam

2021 ◽  
Author(s):  
Anh Kiet Bui ◽  
◽  
Pakawat Sancharoen ◽  
Somnuk Tangtermsirikul ◽  
Ganchai Tanapornraweekit ◽  
...  
Keyword(s):  
Material Properties ◽  
Water Pressure ◽  
Deformation Modulus ◽  
Safety Evaluation ◽  
Arch Dam ◽  
Structural Behaviour ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Concrete Arch Dam ◽  
Dam Concrete

Safety evaluation is an important task to verify performance of a dam during its service. For an old dam, the material properties vary from the designed value significantly affecting structural performance. This study investigates the effects of material properties of dam concrete and foundation rock on the structural behaviour of an old concrete arch dam during operation. The dam safety is evaluated by using a three-dimensional finite element model (FEM). All main loads, such as water pressure, dam self-weight, and thermal load, are considered in the analysis. An existing 54-year-old concrete arch dam, located in a tropical climate region in Thailand, is employed as a case study. The analysis results show that deformation modulus of the foundation, modulus elasticity of concrete, and the variation of reservoir water level during operation are key factors affecting the dam response. With a deformability modulus of foundation and elasticity modulus of dam concrete, which are about 20 GPa and 44.2 GPa, respectively, a good agreement in dam deflections between the analysis and the current monitored data from plumb line equipment can be obtained. It should be noted that the material properties are different from designed value significantly. Finally, safety evaluation can be properly conducted based on current material properties.

scholarly journals The Monitoring-Based Analysis on Deformation-Controlling Factors and Slope Stability of Reservoir Landslide: Hongyanzi Landslide in the Southwest of China

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Bing Han ◽  
Bin Tong ◽  
Jinkai Yan ◽  
Chunrong Yin ◽  
Liang Chen ◽  
...  
Keyword(s):  
Water Level ◽  
Water Pressure ◽  
Monitoring Program ◽  
Significant Risk ◽  
Controlling Factors ◽  
Seepage Water ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Reservoir Area ◽  
Reservoir Landslide

Reservoir landslide is a type of commonly seen geological hazards in reservoir area and could potentially cause significant risk to the routine operation of reservoir and hydropower station. It has been accepted that reservoir landslides are mainly induced by periodic variations of reservoir water level during the impoundment and drawdown process. In this study, to better understand the deformation characters and controlling factors of the reservoir landslide, a multiparameter-based monitoring program was conducted on a reservoir landslide—the Hongyanzi landslide located in Pubugou reservoir area in the southwest of China. The results indicated that significant deformation occurred to the landslide during the drawdown period; otherwise, the landslide remained stable. The major reason of reservoir landslide deformation is the generation of seepage water pressure caused by the rapidly growing water level difference inside and outside of the slope. The influences of precipitation and earthquake on the slope deformation of the Hongyanzi landslide were insignificant.

Dam Safety Reliability Analysis Based on Artificial Neural Network

2011 ◽  
Vol 255-260 ◽  
pp. 3620-3625
Author(s):  
Hai Wei ◽  
Hua Shu Yang ◽  
Liang Wu ◽  
Yue Gui
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Water Level ◽  
Reliability Index ◽  
Safety Evaluation ◽  
Mathematic Model ◽  
Dam Safety ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Artificial Neural

There are many factors, such as climate, flood, material, geology, structure, management, to influence dam safety. So dam safety evaluation, involving many fields, is very complicated, and very difficult to establish mathematic model for assessment. Artificial Neural Network (ANN) has many obvious advantages to deal with these problems influenced by multi-factor, consequently is widely used in engineering fields. This paper considered water level, temperature, main factors influencing dam deformation, as random variables, employed ANN and statistical model to establish performance function of dam hidden trouble deformation and abnormal deformation. Then reliability theory was used to analyze dam safety reliability and sensitivity. The results show that temperature has great effect on probability of dam hidden trouble deformation and abnormal deformation than reservoir water level, due to great variability of temperature. Change of Reliability index of dam is contrary to reservoir water level. Temperature, especially average temperature in 10 days and 5 days, has great effect on sensitivity of reliability index than water level.

scholarly journals Interpretasi Instrumentasi Piezometer Dalam Rangka Pemantauan Keamanan Bendungan Kedung Ombo

2021 ◽  
Vol 7 (2) ◽  
pp. 131-145
Author(s):  
Gerald Guntur Pandapotan Siregar ◽  
Fajar aldoko Kurniawan
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Water Level Fluctuations ◽  
Embankment Dam ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Embankment Dams ◽  
The World ◽  
Earthfill Dams

The embankment dam is the most widely built dam in the world, especially in Indonesia. However, embankment dams are also prone to collapse. Dam failures due to the piping process through the dam body account for 30.5% of the total dam collapses worldwide. Therefore, it is necessary to periodically monitor and evaluate the condition of pore water pressure and seepage in a dam which is usually carried out using installed instrumentation. Very little has been done on instrumentation interpretation of earthfill dams in Indonesia, which is a very worrying condition. It is possible that old or even new dams have shown behavior that leads to a decrease in safety. This condition can be monitored by instrumentation in the dam if interpreted properly. Kedung Ombo Dam as an old embankment dam but has a fairly complete instrumentation can be evaluated for safety related to pore water pressure and phreatic line (seepage line). Pore water pressure evaluation is carried out by collecting piezometer readings and reservoir water level fluctuations over a period of several years. The results of the research on the interpretation of piezometer readings indicate that the overall safety of the Kedung Ombo dam is still good in terms of pore water pressure conditions. However, there are some anomalous conditions that should be investigated further

Stability of No 7 Landslide Located at Ciha Gorge under the Condition of Reservoir Water Level Rise

2011 ◽  
Vol 368-373 ◽  
pp. 1482-1486
Author(s):  
Yan Hui Song ◽  
Ying Wang ◽  
Min Qi Huang
Keyword(s):  
Shear Strength ◽  
Water Level ◽  
Slip Band ◽  
Water Pressure ◽  
Work Conditions ◽  
Stability Factor ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Stability Calculation ◽  
The Stability

Engineering geology characteristics of No. 7 landslide located at Ciha Gorge is described and shear strength of the slip band soils is determined. Based on the above, unbalanced pushing force method is used to calculate the stability factor of the landslide the under different work conditions. It shows that the influence of the reservoir water level rising on the No. 7 landslide mainly includes two points: (1) water makes the shear strength of slip band soils reduced and thus result in the reduction of the stability factor; (2) the rising of reservoir water level also exerts water pressure to the surface of landslide body, and this is beneficial to landslide stability. Calculation results show that with the rising of reservoir water level the stability factor will experience beginning’s reducing followed by later increasing. The minimum stability factor in the process of impounding is 1.05 and it will be 1.08 when reservoir water level reaches to normal impounded level. This shows that No. 7 landslide will maintain elemental stability status in the all process of impounding.

Mechanical Properties of Interface Between Soil-Macadam Aggregate and Concrete Pile

2011 ◽  
Vol 368-373 ◽  
pp. 230-233 ◽  
Author(s):  
Shao Jun Li ◽  
Fan Zhen Meng ◽  
Jing Chen ◽  
Hong Min
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Safety Evaluation ◽  
Friction Angle ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Direct Shear Tests ◽  
Concrete Pile ◽  
Shearing Strength ◽  
Reinforcement Design

The mechanical properties of interface between soil-macadam aggregate and anti-sliding concrete pile are very important for the reinforcement design and safety evaluation of accumulative landslide in the reservoir area of Three Gorges. Soil-macadam aggregate is a complex geomaterial whose properties are totally different with soil or rock. Based on a practical landslide suffering the influence of reservoir water level change and seasonal rainfall, a series of direct shear tests are conducted to investigate the interface mechanical properties between soil-macadam aggregate and concrete pile. Accordingly, the relationship between shear strength parameters and water contents and macadam ratios is presented. The change characteristics of mechanical properties of interface are discussed. The results indicate that shearing strength, inner friction angle and cohesion decrease with less water content. However, as the increment of macadam ratios, the cohesion will decrease gradually, but the shear strength and inner friction angle of interface decrease firstly and then increase after a critical value, the change trend obeys parabolic relation.

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 Fluctuation Effect of Reservoir Water Level on the Seepage of Earth-Fill Dam

2021 ◽  
Vol 9 (6) ◽  
pp. 11-19
Author(s):  
R. Asmaranto ◽  
D. Sisinggih ◽  
R.N.A Rastanto
Keyword(s):  
Water Level ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Water Levels ◽  
Water Infiltration ◽  
Seepage Discharge ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Critical Discharge ◽  
Earth Fill

Lots of dam failures are the result of uncontrolled seepage. The collapse of the Situ Gintung Dam in Tangerang, Banten-Indonesia in 2009 due to heavy rains caused the dam structure to collapse. This is due to increased pore water pressure in the landfill. To anticipate collapse due to uncontrolled seepage, it is necessary to monitor it based on the behavior of changes in rainfall and reservoir water levels. Seepage within the dam body is often monitored using instrumentation tools such as standpipe piezometer (standpipe piezometer) or electric piezometer. But often the piezometer cannot work properly because it is clogged, so it cannot monitor the condition of the seepage. Other instrumentations such as V-Notch are also used to measure seepage discharge. This study aims to determine the behavior of changes in the reservoir water level caused by changes in rainfall and its effect on body seepage of the earth-fill Type dam. By knowing the phenomenon of the behavior of the relationship between reservoir water infiltration and rainfall, it will obtain information on rainfall that endangers the dam which will affect the downstream. In this study, a case study of the Selorejo Dam was taken which has a large enough reservoir capacity of about 31 million m3 which is included in the Brantas River Basin. The results showed that 5 piezometers devices were damaged (SL 1, SL 2, SL 4, SL 6, and SL 7) where they could not read the phreatic water level properly, and 2 piezometers were less sensitive to reading fluctuations in reservoir water levels. namely SL 10 and SL 11 which showed R2 values of 29.78% and 39.4%, respectively. While the maximum seepage discharge is recorded at 1474 liters/minute, this is still below the critical discharge of 1630 liters/minute allowed for this dam, but this needs to be a concern, especially the discharge from toe drain from the left side seepage and C-area which is the leakage from the left support pedestal also contributes a larger discharge than other observation points.

scholarly journals Slope stability analysis considering seepage and stress coupling under water level fluctuation

2021 ◽  
Vol 276 ◽  
pp. 01028
Author(s):  
Zhou YiLiang ◽  
Li Ming ◽  
Li ZiLong
Keyword(s):  
Slope Stability ◽  
Water Level ◽  
Factor Of Safety ◽  
Coupling Effect ◽  
Water Pressure ◽  
Water Level Fluctuation ◽  
Level Fluctuation ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Stability Calculation

The reservoir water level fluctuation is an important factor inducing the reaction of pore-water pressure, seepage and at last resulting in instability and failure of the slope. A typical homogeneous slope is conducted as an example in this paper, the seepage and stress coupling effect is considered, and the slope stability calculation and analysis are carried out by using the finite element stress method. The results demonstrate that the factor of safety increases with the reservoir water level rises, and then gradually changes from decrease to stabilization. It should be noted that the factor of safety decreases slightly during the initial stage of water level rising at the speed of 0.2 m/d, which the slope will probably lose its stability. On the other, the factor of safety changes from decrease to increase along with the reservoir water level drawdown, and then gradually tends to stabilization. There is a minimum factor of safety when the water level is at about 1/4 of the slope height, and the minimum factor of safety decreases with increasing drawdown speed, just as the factor of safety decreases from 0.83 to 0.73 when the drawdown speed is increased from 0.20 m/d to 5.0 m/d.

scholarly journals Static analysis of a high arch dam

2019 ◽  
pp. 45-57
Author(s):  
Yaser Ghafoori ◽  
Andrej Kryžanowski ◽  
Dejan Zupan
Keyword(s):  
Water Level ◽  
Static Analysis ◽  
Three Dimensional ◽  
Water Reservoir ◽  
Arch Dam ◽  
Three Dimensional Model ◽  
High Arch Dam ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Arch Dams

The paper presents the design and static analysis of a high arch dam. A feasibility study was conducted on the dam in the 90s and a preliminary layout was designed. However, the dam’s construction phase has been never started. In this paper, the design and layout of the dam under consideration are in accordance with the US manuals for the design of arch dams. The structure’s three-dimensional model was entered into the program SAP2000 and three-dimensional solid finite elements were used to discretize the model. This paper considers the hydrostatic pressure of the water reservoir and concrete self-weight. The analysis was performed for both the maximum and the minimum designed water level and for the case when the reservoir is empty. Special attention is given to the boundary conditions of the dam at its abutments and foundation. The results show that the planned layout is good for the dam’s construction. The arch dam’s curve transfers the loads to the abutments. The significant role of the foundation rigidity and the reservoir water level in the stress distribution and nodal displacements within the arch dam is observed.

Integrative seismic safety evaluation of a high concrete arch dam

2014 ◽  
Vol 67 ◽  
pp. 85-101 ◽  
Author(s):  
M.A. Hariri-Ardebili ◽  
M.R. Kianoush
Keyword(s):  
Safety Evaluation ◽  
Arch Dam ◽  
Seismic Safety ◽  
Concrete Arch Dam ◽  
Seismic Safety Evaluation
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