Embankment dams come in two types the rock-filled dam and the earth-filled dam made of compacted earth (also called an earthen dam or terrain dam). In this analysis we deal with Queensland dam. Analysis has been done using the Geo studio software and the results discussed.
Configuration
Properties of the earth dam
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|
Dam Dimensions |
|||||||
|
Hunfilled water |
Hservice |
Hfoundation |
Hfilter |
HC-E |
Ltop |
S1 |
S2 |
|
(m) |
(m) |
(m) |
(m) |
(m) |
(m) |
(m) |
(m) |
|
1.9 |
22.8 |
16 |
1.2 |
0 |
6.3 |
3.5 |
2.5 |
|
Material Properties |
|||||||
|
Material |
Undrained |
Effective |
Effective |
Saturated |
Saturated |
coefficient of |
Saturated |
|
kPa |
kPa |
Degree |
kN/m3 |
m3/m3 |
m2/kN |
m/S |
|
|
Core |
68.5 |
7.6 |
30 |
21 |
0.41 |
20.5 *10-5 |
1*10-11 |
|
Embankment |
68.5 |
17 |
26 |
20.5 |
0.33 |
1.6 *10-5 |
3*10-7 |
|
Foundation |
42.6 |
20 |
34 |
19.8 |
0.29 |
1.1 *10-5 |
7.9*10-12 |
|
Filter |
— |
0 |
35 |
21.1 |
0.31 |
0 |
2.54*10-4 |
The client has requested from your design to provide your recommendations on the following points:
1) Model the earth dam in SEEP/W (GeoStudio software) and assign relevant material properties and boundary conditions. Analyze the earth dam for steady-state seepage conditions when the upstream water is at the service level. Using SEEP/W results, calculate the total seepage loss through the dam and foundation per year in m3.
This is the resultant of our geometry
Picture showing the hydraulic conditions
The resultant diagram is as shown
2) Using the results of steady-state seepage analysis (SEEP/W), determine the total head and pore-water pressure at Points “A” and “B” under steady-state seepage conditions with upstream water at the service level. Use following relationships to define the locations of points “A” and “B”.
=3+ =5 x =2 + `=8(1+ )
where, M: mean of the final two digits of all group figures
Ex: figure 01: d ××××56, figure 02: d ××××04, and figure 03: d ××××00, M = 20
Points A and B are shown by 14 and 15 initials
The results for point A are as shown below
(we use the results below to determine the Total head and Pore water pressure of the two points)
Total head is 27.185454
Pore water pressure is 70.467748
For point B
Total head is 26.119675
Pore water pressure is 128.66465
3) Obtain two different flow nets from the above steady-state seepage analysis using SEEP/W (service water level). Using Darcy’s equation for 2-D seepage and Bernoulli’s equation, calculate the total seepage loss through the dam and foundation per year in m3 and the total head and pore-water pressure at Points “A” and “B” for each flow net.
Use only the permeability of embankment soil to estimate the total seepage loss through the dam and foundation. Compare the calculated total seepage loss, total head at A & B, and Pore-water pressure at A & B with the values obtained from SEEP/W ((1) and
(2)).and provide three possible reasons for any deviation
Head at B
heB= 2m
hpB= 13m
therefore total head at B
= 13+2= 15m
Head at A
17+ 2
=19m
Loss in total head between points A and B
= htA- htB
19-15= 4
The gradient of total head
I= change in h÷L
4÷ 22 = 0.18
Using Darcy’s law, the rate of seepage flow:
Since i= 0.18
Q= KiA
= 10-6×i×A
= 10-6×0.18×0.2
=3.6×10-8m3/sec
Pore pressure :
Ρw= 1000kg/m3
G= 9.81 m/sec2
Pore pressure= 1000 ×9.81×water pressure
Pore pressure= 1000 ×9.81×65.413
=641,701.53
4) The council expects to minimise the seepage through the dam by selecting the best material properties for the core of the dam. Using at least four different saturated permeability values for the core of the dam, select optimal saturated permeability for the core of the dam considering the steady-state seepage loss under serviceability conditions (service water level). Typical values of the permeability of core materials are between 1 10-9 m/S and 1 10-14 m/S.
Using the Drucker-Prager assuming that the Drucker-Prager yield surface touches on the interior of the Mohr-Coulomb yield surface
|
Material |
Undrained |
Effective |
Effective |
Saturated |
Saturated |
coefficient of |
Saturated |
|
kPa |
kPa |
Degree |
kN/m3 |
m3/m3 |
m2/kN |
m/S |
|
|
Core |
68.5 |
7.6 |
30 |
21 |
0.41 |
20.5 *10-5 |
1*10-11 |
|
Embankment |
68.5 |
17 |
26 |
20.5 |
0.33 |
1.6 *10-5 |
3*10-7 |
|
Foundation |
42.6 |
20 |
34 |
19.8 |
0.29 |
1.1 *10-5 |
7.9*10-12 |
|
Filter |
— |
0 |
35 |
21.1 |
0.31 |
0 |
2.54*10-4 |
The optimal saturated permeability is 7.9*10-12
5) Using SEEP/W, re-analysis the dam for steady-state seepage when the reservoir water is at the overtopping level. Calculate the total seepage loss per year in m3, total head and pore-water pressure at A & B. Compare these values when the reservoir water is at the service level and give the reasons for differences.
At A
At B
To calculate quantity of water escaping as seepage, following formula can be used;
Seepage water (in m3/Day) = Seepage losses (in m/Day) X Surface area of the pond (in m2)
In this case we calculate as follows:
Surface area of the pond = let’s take 40,000 m2 (Width in meter X Length in meter)
Seepage losses = 9 mm (Soil type: silt,)
Seepage water (in m3/Day) = 360m3 per day
Per year we multiply by 365 days
360×365
=131,400 m3
Head and Pore pressure is calculated as shown below
Using Darcy’s law, the rate of seepage flow:
Since i= 0.18
Q= KiA
= 10-6×i×A
= 10-6×0.18×0.8
=1.44×10-7m3/sec
Pore pressure :
Ρw= 1000kg/m3
G= 9.81 m/sec2
Pore pressure= 1000 ×9.81×water pressure
Pore pressure= 1000 ×9.81×128.66
=1,262,154.60
6) Model the earth dam in SLOPE/W and assign the relevant material properties and boundary conditions. Analyse both the upstream and downstream slopes of the dam for stability after the construction by using Morgenstern-Price, Bishop’s simplified, Janbu’s simplified, Spencer, and Fellenious (Ordinary) methods. Briefly describes the reasons for different factor of safety (FOS) values obtained from different method of analysis for a given slope. Further, provide three recommendations to increase the stability of the dam during/after construction.
Geometry after material allocation
The resultant geometry is as shown
Slice 1 – Morgenstern-Price Method
Factor of Safety 0.133
Phi Angle 0 °
C (Strength) 17 kPa
Pore Water Pressure 0 kPa
Pore Water Force 0 kN
Pore Air Pressure 0 kPa
Pore Air Force 0 kN
Phi B Angle 0 °
Slice Width 0.55004 m
Mid-Height 1.1345 m
Base Length 0.77788 m
Base Angle -45 °
Anisotropic Strength Mod. 1
Applied Lambda 0.1
Weight (incl. Vert. Seismic) 12.792 kN
Base Normal Force -78.951 kN
Base Normal Stress -101.5 kPa
Base Shear Res. Force 13.224 kN
Base Shear Res. Stress 17 kPa
Base Shear Mob. Force 99.527 kN
Base Shear Mob. Stress 127.95 kPa
Left Side Normal Force — kN
Left Side Shear Force — kN
Right Side Normal Force -126.79 kN
Right Side Shear Force -1.5203 kN
Horizontal Seismic Force 0 kN
Point Load 0 kN
Reinforcement Load Used 0 kN
Reinf. Shear Load Used 0 kN
Surcharge Load 0 kN
Polygon Closure 1.4175 kN
Top Left Coordinate 9.6238238, 33.574449 m
Top Right Coordinate 10.173865, 35.293327 m
Bottom Left Coordinate 9.6238238, 33.574449 m
Bottom Right Coordinate 10.173865, 33.024409 m
7) Using SEEP/W & SLOPE/W, calculate the stability (FOS) of the downstream slope of the dam under steady-state conditions at both service and overtopping water levels by using Morgenstern-Price, Bishop’s simplified, Janbu’s simplified, Spencer, and Fellenious (Ordinary) methods. Provide three recommendations to increase the stability of the downstream slope of an earth dam during steady-state seepage condition.
Result showed that average flow rate of leakage under the different mesh size for ilam dam equal 0.836 liters per second for the entire length of the dam.
Slice 28 – Morgenstern-Price Method
Factor of Safety 0.133
Phi Angle 0 °
C (Strength) 17 kPa
Pore Water Pressure 0 kPa
Pore Water Force 0 kN
Pore Air Pressure 0 kPa
Pore Air Force 0 kN
Phi B Angle 0 °
Slice Width 0.47777 m
Mid-Height 3.0984 m
Base Length 0.48884 m
Base Angle -12.219 °
Anisotropic Strength Mod. 1
Applied Lambda 0.1
Weight (incl. Vert. Seismic) 30.346 kN
Base Normal Force 20.614 kN
Base Normal Stress 42.169 kPa
Base Shear Res. Force 8.3103 kN
Base Shear Res. Stress 17 kPa
Base Shear Mob. Force 62.545 kN
Base Shear Mob. Stress 127.95 kPa
Left Side Normal Force 179.3 kN
Left Side Shear Force 5.5245 kN
Right Side Normal Force 122.06 kN
Right Side Shear Force 2.5302 kN
Horizontal Seismic Force 0 kN
Point Load 0 kN
Reinforcement Load Used 0 kN
Reinf. Shear Load Used 0 kN
Surcharge Load 0 kN
Polygon Closure 0.44226 kN
Top Left Coordinate 22.566704, 28.314712 m
Top Right Coordinate 23.04447, 26.987585 m
Bottom Left Coordinate 22.566704, 24.604509 m
Bottom Right Coordinate 23.04447, 24.501045 m
Results showing summary of safety factor for stability SEEP/W & SLOPE/W analysis:
Figure displayed are according to simulation results:
|
Method of analysis |
Upstream slope after construction |
Downstream slope after construction |
Upstream slope in steady stage leakage |
Downstream slope in steady state leakage |
Sudden drop in reservoir water level |
|
Jambu simplified method |
1.9282 |
1.8170 |
1.7119 |
1.8891 |
1.9101 |
|
Bishop simplified method |
2.0191 |
2.2812 |
1.8101 |
2.0101 |
2.1910 |
|
Morgenstern price method |
2.2282 |
2.4722 |
1.9191 |
1.9191 |
2.2292 |
|
Fellenious (Ordinary) method |
1.8190 |
2.1282 |
1.7171 |
1.7181 |
1.9191 |
FOS= 20.6
8) To satisfy the peak water demand of a dry season, water in the reservoir is proposed to release to the water treatment plant in very short time (sudden drawdown). Calculating the stability of upstream slope during drawdown using SEEP/W and SLOPE/W, estimate the safest rapid drawdown level of the reservoir using at least four drawdown levels to ensure the stability of the dam during this operation using Morgenstern-Price method. Assume that 30 days are required to dissipate the excess pore-water pressure from the dam after the rapid-drawdown operation.
Slice 30 – Morgenstern-Price Method
Factor of Safety 0.133
Phi Angle 0 °
C (Strength) 17 kPa
Pore Water Pressure 0 kPa
Pore Water Force 0 kN
Pore Air Pressure 0 kPa
Pore Air Force 0 kN
Phi B Angle 0 °
Slice Width 0.47777 m
Mid-Height 0.62487 m
Base Length 0.48399 m
Base Angle -9.2007 °
Anisotropic Strength Mod. 1
Applied Lambda 0.1
Weight (incl. Vert. Seismic) 6.1201 kN
Base Normal Force -3.1412 kN
Base Normal Stress -6.4902 kPa
Base Shear Res. Force 8.2279 kN
Base Shear Res. Stress 17 kPa
Base Shear Mob. Force 61.925 kN
Base Shear Mob. Stress 127.95 kPa
Left Side Normal Force 62.098 kN
Left Side Shear Force 0.64716 kN
Right Side Normal Force — kN
Right Side Shear Force — kN
Horizontal Seismic Force 0 kN
Point Load 0 kN
Reinforcement Load Used 0 kN
Reinf. Shear Load Used 0 kN
Surcharge Load 0 kN
Polygon Closure 0.98186 kN
Top Left Coordinate 23.522235, 25.660457 m
Top Right Coordinate 24.000001, 24.33333 m
Bottom Left Coordinate 23.522235, 24.410717 m
Bottom Right Coordinate 24.000001, 24.33333 m
The rapid drawdown condition arises when submerged slopes experience a rapid
reduction of the external water level. In a coupled analysis, the magnitude of pore pressure changes depends on the stress-strain behavior of the soil skeleton. In the analysis presented here several elastic soil moduli are consid-ered ( E= 10,000 MPa, 1000 MPa and 100 MPa).
Using the formula
Z0= 2c/y
Y=30
Z0= safest rapid drawdown
Z0= 2× 10,000/20
= 1,000
References
Kamanbedast, A., & Delvari, A. (2012). Analysis of earth dam: Seepage and stability using ansys and geo-studio software. World Applied Sciences Journal, 17(9), 1087-1094.
Maula, B. H., & Zhang, L. (2011). Assessment of embankment factor safety using two commercially available programs in slope stability analysis. Procedia Engineering, 14, 559-566.
Eugster, H., & Nebiker, S. (2008). UAV-based augmented monitoring-real-time georeferencing and integration of video imagery with virtual globes. The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 37(PART B1).
Gopal, P., & Kumar, D. T. K. (2014). Slope stability and seepage analysis of earthern dam of a summer storage tank: A case study by using different approches. International Journal of Innovative Research in Advanced Engineering (IJIRAE), 1(12).
Hakkarainen, M., Woodward, C., & Rainio, K. (2009, October). Software architecture for mobile mixed reality and 4D BIM interaction. In Proc. 25th CIB W78 Conference (pp. 1-8).
Hasani, H., Mamizadeh, J., & Karimi, H. (2013). Stability of slope and seepage analysis in earth fills dams using numerical models (Case Study: Ilam Dam-Iran). World Applied Sciences Journal, 21(9), 1398-1402.
Tatewar, S. P., & Pawade, L. N. (2012). Stability analysis of earth dam by geostudio software. Int. J. civ. Eng. Technol, 3.
Mohammed, M., & Wan, L. (2015). Slope stability analysis of Southern slope of Chengmenshan copper mine, China. International Journal of Mining Science and Technology, 25(2), 171-175.
Kamanbedast, A., & Delvari, A. (2012). Analysis of earth dam: Seepage and stability using ansys and geo-studio software. World Applied Sciences Journal, 17(9), 1087-1094.
Tatewar, S. P., & Pawade, L. N. (2012). Stability analysis of earth dam by geostudio software. Int. J. civ. Eng. Technol, 3.
Gopal, P., & Kumar, D. T. K. (2014). Slope stability and seepage analysis of earthern dam of a summer storage tank: A case study by using different approches. International Journal of Innovative Research in Advanced Engineering (IJIRAE), 1(12).
Arshad, I., Babar, M. M., & Javed, N. (2017). Numerical Analysis of Seepage and Slope Stability in an Earthen Dam by Using Geo-Slope Software. PSM Biological Research, 2(1), 13-20.
Pham, H. T., Oo, H. Z., & Jing, C. (2013). Stability Of slope And Seepage analysis in earth dam using numerical finite element model. Study of Civil Engineering and Architecture.
Zhang, L. M., Xu, Y., Liu, Y., & Peng, M. (2013). Assessment of flood risks in Pearl River Delta due to levee breaching. Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards, 7(2), 122-133.
Kirra, M. S., Shahien, M., Elshemy, M., & Zeidan, B. A. (2015). Seepage and Slope Stability Analysis of Mandali Earth Dam, Iraq: A Case Study. In International Conference on Advances in Structural and Geotechnical Engineering, Hurghada, Egypt.
PS, M. A., & Balan, T. A. Numerical Analysis of Seepage in Embankment Dams.
Mouyeaux, A., Carvajal, C., Peyras, L., Bressolette, P., Breul, P., & Bacconnet, C. (2015). Probability of failure of an embankment dam due to slope instability and overtopping. Russell Michael G, Marc B, Pedro M, Laurent M, 9-11.
Soleimani, S., & Asakereh, A. (2014). EVALUATION OF STATIC STABILITY OF EARTH DAMS USING GEOSTUDIO SOFTWARE (CASE STUDY: NIAN DAM, IRAN). Annals of the Faculty of Engineering Hunedoara, 12(3), 265.
Tatewar, S. P., & Pawade, L. N. (2012). Stability Analysis of Bhimdi Earth Dam. IJEIR, 1(6), 524-527.
Ambikaipahan, R. (2011). Failure of an Earth Dam.
Ghosh, B., & Prasad, S. K. FINITE ELEMENT ANALYSIS OF EARTH DAMS UNDER SEISMIC CONDITION.
Afiri, R., Abderrahmane, S. H., Djerbal, L., & Gabi, S. (2017, July). Stability Analysis of Souk-Tleta Earth Dam, North Algeria. In International Congress and Exhibition” Sustainable Civil Infrastructures: Innovative Infrastructure Geotechnology” (pp. 32-40). Springer, Cham.
Kirra, M. S., Zeidan, B. A., Shahien, M., & Elshemy, M. Seepage Analysis of Walter F. George Dam, USA: A case Study.
Kirra, M. S., Zeidan, B. A., Shahien, M., & Elshemy, M. Seepage Analysis of Walter F. George Dam, USA: A case Study.
Kundagol, P. K., Manjunath, K. V., & Prabhakara, R. DYNAMIC SLOPE STABILITY ANALYSIS OF BLACK COTTON SOIL STABILIZED WITH GGBS AND LIME.
Aein, N. (2015). Evaluating the Behavior of Geogrid-Reinforced Earth Dams under Static and Dynamic Loads. European Online Journal of Natural and Social Sciences: Proceedings, 4(3 (s)), pp-867.
Gabi, S. (2017, July). Stability Analysis of Souk-Tleta Earth Dam, North Algeria. In Numerical Analysis of Nonlinear Coupled Problems: Proceedings of the 1st GeoMEast International Congress and Exhibition, Egypt 2017 on Sustainable Civil Infrastructures (p. 32). Springer.
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