SlideShare a Scribd company logo

WS-D1-CEWRE_PPT.pdf

S
ssuserca460e

This two-day training workshop on engineering design and analysis of embankment dams will cover topics such as understanding different types of dams, schematic layouts of embankment and concrete dams, basic elements and classification of embankment dams, use of local materials in embankment dams, design criteria focusing on stability, zones and slopes, freeboard calculations, and analysis of seepage. The director of the workshop has a PhD in water resources engineering and will introduce the general content outline and understanding of dams and appurtenant hydraulic structures. Key design aspects of embankment dams such as embankment zones, core, and foundations will also be discussed.

Engineering
1 of 65
Download to read offline
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
WS-D1-CEWRE_PPT.pdf
Engineering Design and Analysis of Embankment Dams Two Days Training Workshop 22 – 23 April, 2019
I am Zaheer M. Malik Director Projects (Design & Studies) Ph.D Water Resources Engineering: 2012, CEWRE, UET, Lahore. M.Sc. Hydropower Engineering: 2004, CEWRE, UET, Lahore. B.E. (Civil): 2001, MCE, Risalpur, NUST. Intro!
General content outline ◉Understanding dams ◉Appurtenant hydraulic structures ◉Schematic layouts of dam types ◉Embankment dams Basic elements Classification Use of local materials Design Criteria ◉Focus Items for Consideration Intro General STABILITY Zones and Slopes Overview FREEBOARD Calculations SALIENT DESIGN ASPECTS Embankment Dams (ECRD, CFRD) Internal Erosion ANALYSIS SEEPAGE
Understanding Dams Dams are water retaining structures for damming a riverbed in order to raise the water level and to create an artificial lake (impounding reservoir). EMBANKMENT DAMS These are the most widespread type of dams They are constructed by means of placement and compaction of natural, locally available earthfill and rockfill materials. Their cross-section has the form of a trapezium. CONCRETE DAMS Concrete dams are divided into massive (gravity) dams, roller compacted concrete dams, buttress dams and arch dams. The cross-section of a concrete dam generally approximates the rough form of a triangle, except for the arch dam which has a curved form. Overflowing of water, as a rule, is not allowed for embankment dams! Concrete dams can be constructed as no-overflow dams or overflow dams, since appurtenant hydraulic structures can be carried out relatively simply within the dam wall.
Appurtenant Structures ◉Appurtenant Hydraulic Structures are anticipated within the framework of a dam, for its proper and safe service. ◉Among the general hydraulic structures, the most significant are the spillway and outlet works which, almost without exception, are constructed in every scheme with a dam for conveying and discharging water from the impounded reservoir. ◉Other ancillary facilities are incorporated as necessary during the dam construction and in the service period, like river-diversion structures, intake structures, etc.
Schematic Layouts of Dam Types (a) Homogeneous; (b) zoned; (c) with impermeable face lining, and (d) with an internal core wall made of artificial material (a, b) Gravity (non-overflow, overflow); (c) Buttress, and (d) Arch Embankment Dams Concrete Dams
Typical ECRD Project Layout Plans
Typical CFRD Project Layout Plans
1. Applicable on variable site situations 2. Adaptable to broad foundation conditions 3. Adjustable for use of local materials Embankment Dams A dominant dam type
General Basic Elements Crest (1) is the highest horizontal surface of the dam; Horizontal axis (2) is a line of symmetry of the crest in ground plan, Vertical axis (3) is a normal, drawn through the middle of the crest in the cross-section of the dam. Upstream slope (4) is the face, i.e. the side of the dam towards the water, Downstream slope (5) is the opposite unimmersed side. Contours (6) are the lines along which are connected the slopes of the dam and the ground, forming the heel and the toe of the dam; Foundation (7) is the ground upon which the dam is supported. Height (8) is the distance from the bottom of the excavation for the foundation in the riverbed to the crest of the dam, The level of headwater (9) is the level of water in the impounding reservoir, The height of headwater (10) is the difference between the level of water in the riverbed before construction of the dam and the maximum level of the water in the storage lake. The cross-section (11) is any vertical section, which is perpendicular to the longitudinal axis of the dam. Abutments of a dam are the surfaces of the valley, to the right and to the left of the river bed, upon which the dam is supported; The body of a dam is the volume that is confined within the surface of the foundation, within the slopes, as well as within the crest;
Embankment Dam Classification • Homogeneous • Zoned • Earthfill • Rockfill • Large • Small • Storage • Diversion Purpose Size Structure Material
Use of local materials for embankment dams
General Design Criteria The Dam should function without appreciable deterioration in normal conditions expected to occur in its life. The Dam should be able to avoid catastrophic failure in unusual conditions (most unlikely but possible) which may be imposed. The basic design criteria essentially require an optimized solution for the main dam, to perform most economically together with its foundation and environment.
◉ The dam design should be such as to allow optimum use of materials readily available, standard equipment and normal construction control. ◉ The dam must be safe against overtopping during occurrence of PMF/Design Floods by providing adequate Freeboard. ◉ Seepage through, around and beneath the dam must be controlled to ensure that hydrostatic and seepage forces do not exceed the conditions assumed in the design. ◉ Stability of the structural geometry must be ensured, without impairing the water retaining capability of the dam, under all conditions of construction and reservoir operation, including rapid drawdown of the reservoir and seismic forces. Embankment Dam Design Criteria
Focus items for consideration Over- topping Stability Seepage
Freeboard Riprap (Upstream Slope Protection) Crest Camber Overtopping
Freeboard Protection against overtopping ◉ FREEBOARD for a dam is the vertical distance between a specified reservoir water surface level and the crest of the dam, without allowance for camber of the crest of the dam; ◉ The Objective of having freeboard is to provide assurance against overtopping resulting from wind set up and wave run up.
Methods for determining the Fetch length (over-water distance the wind blows) Effective Fetch … Saville et. al. (1962) Fetch … USBR (2012) A trial and error approach was used to select the critical position on the dam and direction of the central radial to give the maximum effective fetch. The radials spanning 45° on each side of the central radial were used to compute the effective fetch. The recommended procedure for estimating the fetch consists of constructing nine radials from the point of interest at 3-degree intervals. This calculation should be performed for several directions (of the central radial) approaching the dam, including the direction where the central radial is normal to the dam axis and also the direction where the total spread results in the longest possible set of radials.
Example of Comparative Fetch Determination
Example of Fetch Computations Fetch Computations: Length of Radials (m) β Fetch F1 Fetch F2 Fetch F3 Deg NFSL MWSL NFSL MWSL NFSL MWSL 12 1600.899 1629.450 1163.148 1554.869 1540.848 1579.793 9 1617.224 1951.103 1347.444 1377.781 1549.493 1710.634 6 1710.262 1831.945 1357.908 1591.638 1643.733 1684.321 3 1688.693 1977.151 1349.966 1670.758 1772.179 2475.923 0 (Main Radial) 3359.680 3578.975 2143.772 2286.335 3031.496 3053.091 3 2667.591 2853.058 2065.752 2085.889 2695.794 2730.275 6 2096.721 2126.492 1248.612 1715.622 2524.572 2977.707 9 1881.660 2241.555 1170.427 1510.267 2336.228 2566.435 12 1665.171 1884.812 1192.835 1376.275 2347.487 2493.677 Average Fetch (kms) = 2.032 2.231 1.449 1.685 2.160 2.364 Fetch Angle (β°) 45.020 45.020 0.000 0.000 24.590 24.590
Important Terminologies in Freeboard Computations Unit (Color) Legends: [F (km)], [Vw (km/hr)], [T(sec)], [Hs, L, S, R, D (m)] [F (miles)], [Vw (mi/hr)], [T(sec)], [Hs, L, S, R, D (ft)] Wind Setup: 𝑆 = 𝑉 𝑤 2 𝐹 /62000D 𝑆 = 𝑉 𝑤 2 𝐹 /1400D Wave Length: 𝐿 = 1.5 𝑇 2 𝐿 = 5.12 𝑇 2 Wave Period: 𝑇 = 0.0335 𝐹 0.33 𝑉 𝑤 0.33 1.1 + 0.01𝑉 𝑤 0.167 𝑇 = 0.464 𝐹 0.33 𝑉 𝑤 0.33 1.1 + 0.0156𝑉 𝑤 0.167 Wave Height: 𝐻𝑠 = 0.00366 𝐹 0.5 𝑉 𝑤 1.1 + 0.01𝑉 𝑤 0.5 𝐻𝑠 = 0.0245 𝐹 0.5 𝑉 𝑤 1.1 + 0.0156𝑉 𝑤 0.5 Wave Runup: 𝑅 = 𝐻𝑠 𝐴ξ𝑝 + 𝐶 𝛾𝑟𝛾𝑏𝛾ℎ𝛾𝛽
Example of Freeboard Computations Fetch km ECRD CFRD ECRD CFRD <1.6 1.200 1.800 0.900 1.350 1.6 1.500 2.250 1.200 1.800 4 1.800 2.700 1.500 2.250 8 2.400 3.600 1.800 2.700 16 3.000 4.500 2.100 3.150 Freeboard for Preliminary Studies Reference: Normal Minimum Fell, et al. (2015) Fetch angle β RH 0 1 20 0.96 40 0.9 60 0.84 80 0.75 y = -2E-05x2 - 0.0017x + 0.9997 R² = 0.9988 0 0.5 1 1.5 0 20 40 60 80 100 Wave Height Reduction Factor, R H Angle of Main Radial with Normal to Dam Axis, β Wave height reduction due to angular spread Series1 Poly. (Series1) Detailed Freeboard Computations
Riprap Upstream Slope Protection ◉ Median Weight: 𝑊50 = 𝛾𝑟𝐻3 𝐾𝑅𝑅 𝐺𝑠−1 3 cot 𝜃 ◉ Volume: W / ɣr ◉ Diameter: (V / 0.75)1/3 ◉ Thickness: 2D50 lbs kg ft3 m3 ft mm 100 1484 673 8.65 0.24 2.26 689 70 90 742 337 4.32 0.12 1.79 547 35 55 371 168 2.16 0.06 1.42 434 0 20 46 21 0.27 0.01 0.71 217 Wmax = 4 W50 0.5 Wmax W50 Wmin = W50 / 8 20% Band Riprap Specification % Finer Size Coarse Limit Fine Limit Weight Volume (W / ɣr) Diameter (V / 0.75)1/3 {H=H10=1.27Hs}
Crest Width and typical details ◉ Crest Width is usually defined by practical considerations, like construction limitations, roadway requirements, seismically active areas, etc.; ◉ The smallest crest width, for small dams can be 3 – 4 m while for large dams it is 5 – 6 m. The crest width can also be approximated by means of empirical formulae, as a function of the dam’s height e.g.: 𝑏 = 3.6 3 𝐻 − 3. 𝑏 = 0.2𝐻 + 3. 𝑏 = 1 + 𝐴 𝐻 … (A=1.1 – 1.65)
Camber Protection against overtopping ◉ CAMBER is provided along the crest of embankment dams, with the objective of ensuring that the crest elevation remains at or above the design crest elevation and that the freeboard will not be diminished after settlement. ◉ The most practical method of camber design is to apply the “1 percent rule”.
Example of Camber Profile ◉ 1 % of the embankment height is calculated for various stations along the embankment. Then, the numbers are added to the post-construction foundation settlements to arrive at a required camber height.
Example of Camber Profile 968.00 968.10 968.20 968.30 968.40 968.50 968.60 968.70 00+000 00+025 00+050 00+075 00+100 00+125 00+150 00+175 00+200 00+225 00+250 00+275 00+300 00+325 00+350 00+375 00+400 00+425 00+450 00+475 00+500 00+525 00+550 00+575 00+600 00+625 00+650 00+675 Dam Crest El. (m) Dam Centreline RD (m) Parabolic Camber Profile Linear Camber Profile Overall Camber Calculated ◉ The provided camber maintains incremental elevations across the embankment sections within the valley floor and is roughly proportional to the height of the embankment above its foundation.
Embankment Dam Zones and Filters General Design Features of ECRD General Design Features of CFRD Seepage Control
Embankment Dam Zones
Schematic Presentation of a Filter (1) Basic material; (2) Filtering layers; (3) Drainage.
Filter Design Basics
36" 24" 12" 9" 6" 4" 3" 2" 1½" 1" 3/4" 1/2" 3/8" #4 #8 #10 #16 #20 #30 #40 #50 #60 #100 #140 #200 0 10 20 30 40 50 60 70 80 90 100 0.001 0.01 0.1 1 10 100 1000 Percentage Passing Grain Size in Millimeters Sieve Size/No. Boulders Cobbles Gravel Coarse Sand Medium Sand Fine Sand Silt Clay Sample Filter Gradations ECRD CFRD Flow Chart for Base Soil Selection
Conditions encountered in embankment dam zones and how they are protected by filters.
Internal erosion and piping is ignored mainly because the main focus is usually the adequacy of the spillway and slope stability.
Earth Core Rockfill Dam General Design Features of ECRD
Typical ECRD Sections Zone Descriptions: 1 Impervious Core, 2A Fine Filter, 2B Coarse Filter, 2C Bedding, 3 Rockfill, 4 Riprap  Foundation cutoffs are to be tied up with bedrock for positive seepage cutoff expected through core trench at abutments and slurry trench wall in the riverbed reach.  Upstream impervious blanket is provided for lengthening the seepage path where depth to bedrock is unpractical.
Typical Cutoff Wall Profile 0 50 100 Clamshell Backhoe 30 15 Excavation Depths (m) Extensive situations Less common Typical range Basic Types By Funtion Cutoff Barrier Diaphragm Wall By Composition Soil-Bentonite Cement-Bentonite Critical Criteria Permeability Permanence Deformability Strength
Partial Cutoff Wall Cutoff Wall permeability Thickness of Cutoff Wall qf = rate of underseepage with foundation seepage control in m3 /sec d = penetration depth of cutoff wall in m W = open area in positive cutoff in m2 5 10 15 20 25 30 0.00E+00 1.00E-03 2.00E-03 3.00E-03 4.00E-03 5.00E-03 0 500 1000 1500 2000 2500 Rate of underseepage (qf), cumecs Lo = Discontinuous upstream impervious blanket length,meter 0.500 0.600 0.700 0.800 0.900 1.000 0 500 1000 1500 2000 2500 Flow Efficiency Lo = Discontinuous upstream impervious blanket length,meter Select L0 from table, assuming L3 = 0 450 10 h ZDesign 10% of head = 0.1h = 4.5 a. Corresponding L1 = = 402.7871752 8.95 h 750 16.67 h Z2 5% of head = 0.05h = 2.25 b. Corresponding 530.3300859 11.79 h Difference (b-a) = 127.543 2.83 h Zmin USBR (1987) Design of Small Dams 1.00 m c. Corresponding 353.5533906 7.86 h Selected upstream impervious blanket dimensions: Design thickness for blanket z bR = 0.1h = 4.5 m Effective length for z bR = ~ 9h = 405 m OK Half design thickness for blanket z 1 = 0.05h = 2.25 m Effective length (transition) for z 1 = ~ 3h = 135 m OK Minimum blanket thickness z min = 1 m Allowable effective length (remaining) for z min = ~ 8h = 360 m OK Provided discontinuous length L o = ~ 20h = 900 m OK ≈ ≈ Dam Crest Elevation 968 m Normal Conservation Level 961 m Riverbed Level 916 m Foundation permeability Kf = K˳= 2.50E-04 m/sec Core base width L2 = B = 25 m Head over foundation h= 45 m Depth of foundation D= (≈h) 50 m Initial Trial with No underseepage control Rate of underseepage Qo = = 2.25E-02 m3 /sec (Theoretical) Upstream Impervious Blanket Permeability of blanket KbR = 1.00E-07 m/sec Thickness of blanket zbR = 0.1 h 4.5 m Factor = 0.001333333 1/m Lo = discontinuous upstream impervious blanket length L1 = effective upstream impervious blanket length (Assuming L3 = 0) (m) (m3 /sec) 100 99.412 4.521E-03 0.799 200 195.390 2.552E-03 0.887 300 284.962 1.815E-03 0.919 400 365.944 1.439E-03 0.936 500 437.087 1.217E-03 0.946 600 498.028 1.075E-03 0.952 700 549.108 9.798E-04 0.956 800 591.152 9.129E-04 0.959 900 625.241 8.651E-04 0.962 1000 652.546 8.302E-04 0.963 1100 674.205 8.045E-04 0.964 1200 691.251 7.853E-04 0.965 1300 704.586 7.710E-04 0.966 1400 714.968 7.602E-04 0.966 1500 723.021 7.520E-04 0.967 1600 729.248 7.458E-04 0.967 1700 734.054 7.411E-04 0.967 1800 737.756 7.375E-04 0.967 1900 740.604 7.347E-04 0.967 2000 742.793 7.326E-04 0.967 Lo (m) USACE (1993). Seepage Analysis and Control for Dams , Engineer Manual 1110-2- 1901, Department of the Army, U.S. Army Corps of Engineers, Washington, DC, 30 April 1993. qf Thickness of blanket zbR = 0.1 h 4.5 m Factor = 0.001333333 1/m Lo = discontinuous upstream impervious blanket length L1 = effective upstream impervious blanket length (Assuming L3 = 0) (m) (m3 /sec) 100 99.412 4.521E-03 0.799 200 195.390 2.552E-03 0.887 300 284.962 1.815E-03 0.919 400 365.944 1.439E-03 0.936 500 437.087 1.217E-03 0.946 600 498.028 1.075E-03 0.952 700 549.108 9.798E-04 0.956 800 591.152 9.129E-04 0.959 900 625.241 8.651E-04 0.962 1000 652.546 8.302E-04 0.963 1100 674.205 8.045E-04 0.964 1200 691.251 7.853E-04 0.965 1300 704.586 7.710E-04 0.966 1400 714.968 7.602E-04 0.966 1500 723.021 7.520E-04 0.967 1600 729.248 7.458E-04 0.967 1700 734.054 7.411E-04 0.967 1800 737.756 7.375E-04 0.967 1900 740.604 7.347E-04 0.967 2000 742.793 7.326E-04 0.967 Lo (m) USACE (1993). Seepage Analysis and Control for Dams , Engineer Manual 1110-2- 1901, Department of the Army, U.S. Army Corps of Engineers, Washington, DC, 30 April 1993. qf
Concrete Face Rockfill Dam (Face Slab connected with a Foundation Plinth) General Design Features of CFRD Zone Descriptions: 1A: Face protection zone, Joint or crack healer, cohesionless fine grained soil 1B: Random fill, support to 1A 2A: Perimeter filter zone, 2B: Face support zone, processed (-75mm particle size) 3A: Selected rockfill, (0.4m layers) 3B and 3C: Quarry run rockfill (1m and 2m layers).
CFRD Design Elements Design of CFRD plinth includes dimensions for its thickness and width, followed by its geometric layout and alignment Where: A = Foundation Type B = Foundation Class C = Min. Ratio: Plinth Width/Water Depth (Full Reservoir) D = Rock Quality Designation (RQD in %) E = Weathering Degree: I = sound rock; VI = residual soil F = Consistency Degree: 1 = very hard rock; 6 = friable rock G = Weathered Macro Discontinuities per 10 m H = Excavation Classes: 1=requires blasting 2=requires heavy rippers; some blasting 3=can be excavated with light rippers 4=can be excavated with dozer blade Design of CFRD face slabs begins with the selection of slab thickness, width and location of vertical and horizontal joints. *H = Head of water above plinth in meters
WS-D1-CEWRE_PPT.pdf
CFRD Plinth Alignment and Face Slab Layout Points Easting Northing Elevation ΔEl LPlan θ n h 1 315297.40 3351824.71 1832.5 35.5 60.71 41.25 2.27 0.92 2 315236.69 3351877.96 1797 0 55.00 0.00 0 1.00 3 315181.69 3351877.96 1797 -35.5 74.29 -35.63 -2.57 0.93 4 315107.40 3351824.71 1832.5 ∆𝐸𝑙 = 𝐸𝑙𝑖 − 𝐸𝑙𝑗 𝜃 = tan−1 ∆𝐸𝑙 × 𝑚 𝐿𝑝𝑙𝑎𝑛 𝑛 = 𝑚 sin 𝜃 ℎ = ℎ𝑜 1 + sin 𝜃 𝑚 2
Geological Profile at Upstream Toe for Plinth Alignment
WS-D1-CEWRE_PPT.pdf
CFRD Plinth Alignment and Face Slab Layout
CFRD Plinth Alignment and Face Slab Layout
Typical Plinth Geometry for Different Reaches
Plinth Excavation Details
Methods and Considerations Slope Stability Different shapes of sliding surfaces • Classical – Limit Equilibrium: Method of Slices • Advanced - FEM • Immediately following construction • Full reservoir with established stationary seepage flow • Rapid drawdown of water level
Seepage and Stability Analysis – GeoStudio Results
Seepage and Stability Analysis – Slide Results
Reporting Stability Analysis Results Loading Conditions Critical Consideration Detailed Description Minimum FoS Required Analyzed Normal Long term seepage condition Downstream slope with steady state seepage from reservoir water level at 1139.5 m. amsl. 1.5 1.836 Unusual Short term seepage conditions Details as follows: Unusual-MSL Maximum surcharge pool Downstream slope with steady state seepage from reservoir water level at 1144.5 m. amsl. 1.4 1.836 Unusual-EoC End of Construction Upstream Slope 1.3 2.192 Downstream Slope 1.3 1.844 Unusual-RDD Rapid drawdown Upstream slope with transient seepage resulting from drawdown of reservoir from El. 1139.5 to El. 1126.5 (i.e. normal conservation to dead pool) 1.2 1.92 Unusual-OBE Operational Basis Earthquake (OBE) with normal loading condition Downstream slope with OBE seismic coefficients (0.18g) along with steady state seepage from reservoir water level at 1139.5 m. amsl. 1.1 1.311 Extreme-MCE Maximum Credible Earthquake (MCE) with normal loading condition Downstream slope with MCE seismic coefficients (0.32g) along with steady state seepage from reservoir water level at 1139.5 m. amsl. 1 1.083
Reporting Stability Analysis Results Loading Condition Scenario Slope Face Slab Reservoir Level (m) Seismic Load Required FOS Calculated FOS Normal N1 SS DS Yes 1800 1.5 1.88 N2 EoC DS No 1.4 1.992 N3 EoC US No 1.4 1.547 Unusual U1 SS DS Yes 1802 OBE 1 1.063 U2 SS DS Yes 1800 DBE 1 1.172 U3a EoC DS No OBE 1 1.369 U3b EoC US No OBE 1 1.08 U4 EoC DS No 1800 1.2 1.426 U5a RDD DS No 1800- 1780 1.3 1.881 U5b RDD US No 1800- 1780 1.3 1.503 Extreme E1 SS DS Yes 1800 SEE 1 1.015 E2 EoC DS No 1800 OBE 1 1.011
Typical Cut-Slope Analysis (SLIDE Results)
GARUK DAM: ECRD Other Features
WS-D1-CEWRE_PPT.pdf
Seismic Hazard Assessment Tectonic Feature Fault Type Maximum Magnitude (MW) Closest Distance to Fault (km) Peak Horizontal Ground Acceleration (g) Median Abrahamson-Silva NGA (2008) Boore-Atkinson NGA (2008) Campbell-Bozorgnia NGA (2008) Average PGA 50% 84% 50% 84% 50% 84% 50% 84% Chaman Fault (Naushki Segment) S 7.6 2 0.48 0.82 0.46 0.81 0.56 0.94 0.50 0.86 Ghazaband Fault S 7.6 25 0.15 0.26 0.18 0.32 0.17 0.29 0.17 0.29 PGA (g) OB RP (Yrs) Rock 0.19 145 0.16 0.28 475 0.25 0.36 1,000 0.32 0.49 3,000 0.44 0.67 10,000 0.61 MCE: 0.86g, SEE: 0.50g, OBE: 0.19g (OB), 0.16g (Rock), DBE: 0.28g (OB), 0.25g (Rock) Ref: ICOLD (2016) Bulletin No. 148. Results of Probabilistic Seismic Hazard Analysis Results of Deterministic Seismic Hazard Analysis
WS-D1-CEWRE_PPT.pdf
WS-D1-CEWRE_PPT.pdf
Ortho-Image Grids for Dam Site Aerial Survey Quadcopter used for Aerial Mapping GCPs for Aerial Survey Satellite and Aerial Photogrammetry Digital Terrain Model (DTM) Topographic Survey Plan (at 1m contour interval)
Comparative Survey Results 0 50 100 150 200 910 920 930 940 950 960 970 980 910 920 930 940 950 960 970 980 0 500 1000 1500 2000 Capacity (AF x 1000) Elevation (m amsl) Elevation (m amsl) Area (Acres) Reservoir Surface Area - Conventional Survey Reservoir Surface Area - Satellite DEM Reservoir Surface Area - Aerial Survey Reservoir Capacity - Conventional Survey Reservoir Capacity - Satellite DEM Reservoir Capacity - Aerial Survey Description (Unit) Conventional Survey Satellite Imagery DEM Aerial Survey Dead Storage (Aft) 25,800 25,474 (31.42 MCM) 25,952 (32.01 MCM) Gross Storage (Aft) 50,695 51,649 (63.71 MCM) 53,025 (65.41 MCM) Live Storage (Aft) 24,895 26,175 (32.29 MCM) 27,073 (33.40 MCM) Dead Storage El. (m amsl) 959 951 953 Gross Storage El. (m amsl) 970 961 963 Depth of Live Storage (m) 11 10 10
Issues in dimensioning embankment dams, (a) and (c) are poor practice; (b) is the correct practice
Some References of Interest Robin Fell, Patrick MacGregor, David Stapledon, Graeme Bell, & Mark Foster (2015). Geotechnical Engineering of Dams, 2nd Edition, CRC Press/Balkema, Leiden, Netherlands. ICOLD (2010). Concrete Face Rockfill Dams: Concepts for design and construction, International Commission on Large Dams, Bulletin 141. USACE (1993). Seepage Analysis and Control for Dams, Engineer Manual 1110-2-1901, Department of the Army, U.S. Army Corps of Engineers, Washington, DC, 30 April 1993. USBR (2011). Design Standard No. 13: Embankment Dams. Chapter 5: Protective Filters, Revision 9, Phase 4 (Final). November 2011, United States Bureau of Reclamation [DS-13(5)-9]. USBR (2012). Design Standards No. 13: Embankment Dams, Chapter 6: Freeboard, Revision 2, Phase 4 (Final), September 2012, United States Bureau of Reclamation [DS-13(6)-2]. USBR (2014). Design Standards No. 13: Embankment Dams, Chapter 7: Riprap Slope Protection, Revision 2.1, Phase 4 (Final), May 2014, United States Bureau of Reclamation [DS-13(7)-2.1]. USBR (2014). Design Standards No. 13: Embankment Dams, Chapter 8: Seepage, Revision 4.1, Phase 4 (Final), January 2014, United States Bureau of Reclamation [DS-13(8)-4.1].
Any questions ? You can contact me at ◉ zaheer.malik@pespk.com Thanks!

More Related Content

PPTX
Class lectures on hydrology by Rabindra Ranjan Saha, Lecture 8
World University of Bangladesh
 
PDF
Economic Design of Water Tank of Different Shapes With Reference To IS: 3370 ...
IJMER
 
PPT
Rule level & gate operation
Tushar Dholakia
 
PPTX
Open Channel Flow
Malla Reddy University
 
PPTX
Design of Retaining Wall
Ananthakumar75
 
PDF
3.4 pushover analysis
NASRIN AFROZ
 
PDF
Chapter 4 seepage theories
Mohsin Siddique
 
PDF
5 plastic analysis
Priyabrata Behera
 
Class lectures on hydrology by Rabindra Ranjan Saha, Lecture 8
World University of Bangladesh
 
Economic Design of Water Tank of Different Shapes With Reference To IS: 3370 ...
IJMER
 
Rule level & gate operation
Tushar Dholakia
 
Open Channel Flow
Malla Reddy University
 
Design of Retaining Wall
Ananthakumar75
 
3.4 pushover analysis
NASRIN AFROZ
 
Chapter 4 seepage theories
Mohsin Siddique
 
5 plastic analysis
Priyabrata Behera
 

What's hot (20)

PPTX
Intze ppt
Jayesh Bhanushali
 
PDF
Design of combined footing ppt
Bharti Shinde
 
PPT
Fundamentals of structural analysis
Kathan Sindhvad
 
PPTX
Earthen Dam
Malla Reddy University
 
PPTX
Stability analysis of dam
Sonam Pandey
 
PPTX
Spillways
OmkarRavipudi
 
DOCX
2 marks Question with Answer for Design of Reinforced Cement Concrete Elements
shielaBalanta2
 
PPTX
Topic2_Force Method of Analysis Beam.pptx
Mary Joanne Aniñon
 
PPT
ogee design
Vidhi Khokhani
 
PPTX
Analysis & design of T-Beam bridge
Elamathy Murugan
 
PDF
Rating curve design,practice and problems
Tianjin University China
 
PPTX
Geometric design of railway track
MOHIT DUREJA
 
PDF
2 column
P Ramana
 
PDF
Spillways
Waleed Liaqat
 
PDF
Gravity dam stability analysis
Divya Vishnoi
 
PDF
Gravity dams
MitaliShelke
 
PDF
Seismic design and construction of retaining wall
AhmedEwis13
 
DOCX
i&hs.docx
Mood Naik
 
PDF
Chapter 3 2
shita43
 
PPT
Spillways &amp; energy dissipator
SAGAR RAUT
 
Intze ppt
Jayesh Bhanushali
 
Design of combined footing ppt
Bharti Shinde
 
Fundamentals of structural analysis
Kathan Sindhvad
 
Earthen Dam
Malla Reddy University
 
Stability analysis of dam
Sonam Pandey
 
Spillways
OmkarRavipudi
 
2 marks Question with Answer for Design of Reinforced Cement Concrete Elements
shielaBalanta2
 
Topic2_Force Method of Analysis Beam.pptx
Mary Joanne Aniñon
 
ogee design
Vidhi Khokhani
 
Analysis & design of T-Beam bridge
Elamathy Murugan
 
Rating curve design,practice and problems
Tianjin University China
 
Geometric design of railway track
MOHIT DUREJA
 
2 column
P Ramana
 
Spillways
Waleed Liaqat
 
Gravity dam stability analysis
Divya Vishnoi
 
Gravity dams
MitaliShelke
 
Seismic design and construction of retaining wall
AhmedEwis13
 
i&hs.docx
Mood Naik
 
Chapter 3 2
shita43
 
Spillways &amp; energy dissipator
SAGAR RAUT
 
Ad

Similar to WS-D1-CEWRE_PPT.pdf (20)

PPTX
EARTHERN DAM
Sree Srilatha
 
PPTX
4UB21CV005 PPT.pptx.....................
SahanaSana28
 
PDF
Topic 3 - Earth Dams. Preliminary inf.pdf
chrispusmutethia24
 
PPTX
Design consideration Of Earth Dams
Rosul Ahmed
 
PPTX
DAM ENGINEERING I.pptx
TewodrosAssefaNiguss
 
PPTX
Design of earth dam at gorukallu
rohinibjn
 
PPTX
Introduction to Dams.pptx
PMAS-AAUR
 
PDF
Know_your_Dam__failuers_R.K.G_termes related to dams
FaHima45
 
PPT
03lecture-dams.ppt
RishabhSohal2
 
PDF
Dams and Reservoirs -Hydraulics engineering
Civil Zone
 
PPTX
Case studies of failures of earthen dams
uzma shaikh
 
PPTX
Earthen dam
brijlata sharma
 
PPTX
-- Rockfill-Dam constrcution and design and management
FarukAtalar1
 
PDF
lecturenote_1219301080Chapter 2 Embankment Dam-1 (1).pdf
YeshiharegAlemu
 
PDF
lecturenote_1219301080Chapter 2 Embankment Dam-1 (3).pdf
YeshiharegAlemu
 
PDF
lecturenote_1219301080Chapter 2 Embankment Dam-1 (2).pdf
YeshiharegAlemu
 
PDF
Design_and_Construction_of_Embankment_Da (2).pdf
YeshiharegAlemu
 
PDF
Design_and_Construction_of_Embankment_Da (1).pdf
YeshiharegAlemu
 
PPT
Presas y reservorios, diseño, estudios y diemsionamiento
hanspaul50001
 
PPTX
Dam design
Mohammed Maina
 
EARTHERN DAM
Sree Srilatha
 
4UB21CV005 PPT.pptx.....................
SahanaSana28
 
Topic 3 - Earth Dams. Preliminary inf.pdf
chrispusmutethia24
 
Design consideration Of Earth Dams
Rosul Ahmed
 
DAM ENGINEERING I.pptx
TewodrosAssefaNiguss
 
Design of earth dam at gorukallu
rohinibjn
 
Introduction to Dams.pptx
PMAS-AAUR
 
Know_your_Dam__failuers_R.K.G_termes related to dams
FaHima45
 
03lecture-dams.ppt
RishabhSohal2
 
Dams and Reservoirs -Hydraulics engineering
Civil Zone
 
Case studies of failures of earthen dams
uzma shaikh
 
Earthen dam
brijlata sharma
 
-- Rockfill-Dam constrcution and design and management
FarukAtalar1
 
lecturenote_1219301080Chapter 2 Embankment Dam-1 (1).pdf
YeshiharegAlemu
 
lecturenote_1219301080Chapter 2 Embankment Dam-1 (3).pdf
YeshiharegAlemu
 
lecturenote_1219301080Chapter 2 Embankment Dam-1 (2).pdf
YeshiharegAlemu
 
Design_and_Construction_of_Embankment_Da (2).pdf
YeshiharegAlemu
 
Design_and_Construction_of_Embankment_Da (1).pdf
YeshiharegAlemu
 
Presas y reservorios, diseño, estudios y diemsionamiento
hanspaul50001
 
Dam design
Mohammed Maina
 
Ad

Recently uploaded (20)

PPT
INTRODUCTION -Data Warehousing and Mining-M.Tech- VTU.ppt
Subramanyam Natarajan
 
PDF
Visual Aids for Exploratory Data Analysis.pdf
Ashutosh Satapathy
 
PDF
Unit I ESSENTIAL OF DIGITAL MARKETING.pdf
Nitin Shelake
 
PDF
BIO-INSPIRED HORMONAL MODULATION AND ADAPTIVE ORCHESTRATION IN S-AI-GPT
ijaia
 
PDF
Categorization of Factors Affecting Classification Algorithms Selection
IJDKP
 
PPTX
Safety Seminar civil to be ensured for safe working.
DILJEETKUMAR8
 
PPTX
CURRICULAM DESIGN engineering FOR CSE 2025.pptx
Amuda3
 
PPTX
Artificial Intelligence
dikshendrasarpate2
 
PPTX
Nature of X-rays, X- Ray Equipment, Fluoroscopy
DJERALDINAUXILLIAECE
 
PDF
COURSE DESCRIPTOR OF SURVEYING R24 SYLLABUS
MNANDITHACIVILSTAFF
 
PDF
Soil Improvement Techniques Note - Rabbi
rahmatideal000
 
PDF
737-MAX_SRG.pdf student reference guides
ssusere2119a1
 
PDF
Human-AI Collaboration: Balancing Agentic AI and Autonomy in Hybrid Systems
ijccsa
 
PPTX
Information Storage and Retrieval Techniques Unit III
jeyamohan2519
 
PPTX
introduction to high performance computing
JuanDavid747466
 
PDF
UNIT no 1 INTRODUCTION TO DBMS NOTES.pdf
pawarbhaktiit
 
PDF
A SYSTEMATIC REVIEW OF APPLICATIONS IN FRAUD DETECTION
IJNSA Journal
 
PDF
null (2) bgfbg bfgb bfgb fbfg bfbgf b.pdf
Ramez Hosny
 
PDF
Accra-Kumasi Expressway - Prefeasibility Report Volume 1 of 7.11.2018.pdf
JeorgeWilsonKingson1
 
PDF
III.4.1.2_The_Space_Environment.p pdffdf
sittiporn2
 
INTRODUCTION -Data Warehousing and Mining-M.Tech- VTU.ppt
Subramanyam Natarajan
 
Visual Aids for Exploratory Data Analysis.pdf
Ashutosh Satapathy
 
Unit I ESSENTIAL OF DIGITAL MARKETING.pdf
Nitin Shelake
 
BIO-INSPIRED HORMONAL MODULATION AND ADAPTIVE ORCHESTRATION IN S-AI-GPT
ijaia
 
Categorization of Factors Affecting Classification Algorithms Selection
IJDKP
 
Safety Seminar civil to be ensured for safe working.
DILJEETKUMAR8
 
CURRICULAM DESIGN engineering FOR CSE 2025.pptx
Amuda3
 
Artificial Intelligence
dikshendrasarpate2
 
Nature of X-rays, X- Ray Equipment, Fluoroscopy
DJERALDINAUXILLIAECE
 
COURSE DESCRIPTOR OF SURVEYING R24 SYLLABUS
MNANDITHACIVILSTAFF
 
Soil Improvement Techniques Note - Rabbi
rahmatideal000
 
737-MAX_SRG.pdf student reference guides
ssusere2119a1
 
Human-AI Collaboration: Balancing Agentic AI and Autonomy in Hybrid Systems
ijccsa
 
Information Storage and Retrieval Techniques Unit III
jeyamohan2519
 
introduction to high performance computing
JuanDavid747466
 
UNIT no 1 INTRODUCTION TO DBMS NOTES.pdf
pawarbhaktiit
 
A SYSTEMATIC REVIEW OF APPLICATIONS IN FRAUD DETECTION
IJNSA Journal
 
null (2) bgfbg bfgb bfgb fbfg bfbgf b.pdf
Ramez Hosny
 
Accra-Kumasi Expressway - Prefeasibility Report Volume 1 of 7.11.2018.pdf
JeorgeWilsonKingson1
 
III.4.1.2_The_Space_Environment.p pdffdf
sittiporn2
 

WS-D1-CEWRE_PPT.pdf

  • 2. Engineering Design and Analysis of Embankment Dams Two Days Training Workshop 22 – 23 April, 2019
  • 3. I am Zaheer M. Malik Director Projects (Design & Studies) Ph.D Water Resources Engineering: 2012, CEWRE, UET, Lahore. M.Sc. Hydropower Engineering: 2004, CEWRE, UET, Lahore. B.E. (Civil): 2001, MCE, Risalpur, NUST. Intro!
  • 4. General content outline ◉Understanding dams ◉Appurtenant hydraulic structures ◉Schematic layouts of dam types ◉Embankment dams Basic elements Classification Use of local materials Design Criteria ◉Focus Items for Consideration Intro General STABILITY Zones and Slopes Overview FREEBOARD Calculations SALIENT DESIGN ASPECTS Embankment Dams (ECRD, CFRD) Internal Erosion ANALYSIS SEEPAGE
  • 5. Understanding Dams Dams are water retaining structures for damming a riverbed in order to raise the water level and to create an artificial lake (impounding reservoir). EMBANKMENT DAMS These are the most widespread type of dams They are constructed by means of placement and compaction of natural, locally available earthfill and rockfill materials. Their cross-section has the form of a trapezium. CONCRETE DAMS Concrete dams are divided into massive (gravity) dams, roller compacted concrete dams, buttress dams and arch dams. The cross-section of a concrete dam generally approximates the rough form of a triangle, except for the arch dam which has a curved form. Overflowing of water, as a rule, is not allowed for embankment dams! Concrete dams can be constructed as no-overflow dams or overflow dams, since appurtenant hydraulic structures can be carried out relatively simply within the dam wall.
  • 6. Appurtenant Structures ◉Appurtenant Hydraulic Structures are anticipated within the framework of a dam, for its proper and safe service. ◉Among the general hydraulic structures, the most significant are the spillway and outlet works which, almost without exception, are constructed in every scheme with a dam for conveying and discharging water from the impounded reservoir. ◉Other ancillary facilities are incorporated as necessary during the dam construction and in the service period, like river-diversion structures, intake structures, etc.
  • 7. Schematic Layouts of Dam Types (a) Homogeneous; (b) zoned; (c) with impermeable face lining, and (d) with an internal core wall made of artificial material (a, b) Gravity (non-overflow, overflow); (c) Buttress, and (d) Arch Embankment Dams Concrete Dams
  • 8. Typical ECRD Project Layout Plans
  • 9. Typical CFRD Project Layout Plans
  • 10. 1. Applicable on variable site situations 2. Adaptable to broad foundation conditions 3. Adjustable for use of local materials Embankment Dams A dominant dam type
  • 11. General Basic Elements Crest (1) is the highest horizontal surface of the dam; Horizontal axis (2) is a line of symmetry of the crest in ground plan, Vertical axis (3) is a normal, drawn through the middle of the crest in the cross-section of the dam. Upstream slope (4) is the face, i.e. the side of the dam towards the water, Downstream slope (5) is the opposite unimmersed side. Contours (6) are the lines along which are connected the slopes of the dam and the ground, forming the heel and the toe of the dam; Foundation (7) is the ground upon which the dam is supported. Height (8) is the distance from the bottom of the excavation for the foundation in the riverbed to the crest of the dam, The level of headwater (9) is the level of water in the impounding reservoir, The height of headwater (10) is the difference between the level of water in the riverbed before construction of the dam and the maximum level of the water in the storage lake. The cross-section (11) is any vertical section, which is perpendicular to the longitudinal axis of the dam. Abutments of a dam are the surfaces of the valley, to the right and to the left of the river bed, upon which the dam is supported; The body of a dam is the volume that is confined within the surface of the foundation, within the slopes, as well as within the crest;
  • 12. Embankment Dam Classification • Homogeneous • Zoned • Earthfill • Rockfill • Large • Small • Storage • Diversion Purpose Size Structure Material
  • 13. Use of local materials for embankment dams
  • 14. General Design Criteria The Dam should function without appreciable deterioration in normal conditions expected to occur in its life. The Dam should be able to avoid catastrophic failure in unusual conditions (most unlikely but possible) which may be imposed. The basic design criteria essentially require an optimized solution for the main dam, to perform most economically together with its foundation and environment.
  • 15. ◉ The dam design should be such as to allow optimum use of materials readily available, standard equipment and normal construction control. ◉ The dam must be safe against overtopping during occurrence of PMF/Design Floods by providing adequate Freeboard. ◉ Seepage through, around and beneath the dam must be controlled to ensure that hydrostatic and seepage forces do not exceed the conditions assumed in the design. ◉ Stability of the structural geometry must be ensured, without impairing the water retaining capability of the dam, under all conditions of construction and reservoir operation, including rapid drawdown of the reservoir and seismic forces. Embankment Dam Design Criteria
  • 16. Focus items for consideration Over- topping Stability Seepage
  • 17. Freeboard Riprap (Upstream Slope Protection) Crest Camber Overtopping
  • 18. Freeboard Protection against overtopping ◉ FREEBOARD for a dam is the vertical distance between a specified reservoir water surface level and the crest of the dam, without allowance for camber of the crest of the dam; ◉ The Objective of having freeboard is to provide assurance against overtopping resulting from wind set up and wave run up.
  • 19. Methods for determining the Fetch length (over-water distance the wind blows) Effective Fetch … Saville et. al. (1962) Fetch … USBR (2012) A trial and error approach was used to select the critical position on the dam and direction of the central radial to give the maximum effective fetch. The radials spanning 45° on each side of the central radial were used to compute the effective fetch. The recommended procedure for estimating the fetch consists of constructing nine radials from the point of interest at 3-degree intervals. This calculation should be performed for several directions (of the central radial) approaching the dam, including the direction where the central radial is normal to the dam axis and also the direction where the total spread results in the longest possible set of radials.
  • 20. Example of Comparative Fetch Determination
  • 21. Example of Fetch Computations Fetch Computations: Length of Radials (m) β Fetch F1 Fetch F2 Fetch F3 Deg NFSL MWSL NFSL MWSL NFSL MWSL 12 1600.899 1629.450 1163.148 1554.869 1540.848 1579.793 9 1617.224 1951.103 1347.444 1377.781 1549.493 1710.634 6 1710.262 1831.945 1357.908 1591.638 1643.733 1684.321 3 1688.693 1977.151 1349.966 1670.758 1772.179 2475.923 0 (Main Radial) 3359.680 3578.975 2143.772 2286.335 3031.496 3053.091 3 2667.591 2853.058 2065.752 2085.889 2695.794 2730.275 6 2096.721 2126.492 1248.612 1715.622 2524.572 2977.707 9 1881.660 2241.555 1170.427 1510.267 2336.228 2566.435 12 1665.171 1884.812 1192.835 1376.275 2347.487 2493.677 Average Fetch (kms) = 2.032 2.231 1.449 1.685 2.160 2.364 Fetch Angle (β°) 45.020 45.020 0.000 0.000 24.590 24.590
  • 22. Important Terminologies in Freeboard Computations Unit (Color) Legends: [F (km)], [Vw (km/hr)], [T(sec)], [Hs, L, S, R, D (m)] [F (miles)], [Vw (mi/hr)], [T(sec)], [Hs, L, S, R, D (ft)] Wind Setup: 𝑆 = 𝑉 𝑤 2 𝐹 /62000D 𝑆 = 𝑉 𝑤 2 𝐹 /1400D Wave Length: 𝐿 = 1.5 𝑇 2 𝐿 = 5.12 𝑇 2 Wave Period: 𝑇 = 0.0335 𝐹 0.33 𝑉 𝑤 0.33 1.1 + 0.01𝑉 𝑤 0.167 𝑇 = 0.464 𝐹 0.33 𝑉 𝑤 0.33 1.1 + 0.0156𝑉 𝑤 0.167 Wave Height: 𝐻𝑠 = 0.00366 𝐹 0.5 𝑉 𝑤 1.1 + 0.01𝑉 𝑤 0.5 𝐻𝑠 = 0.0245 𝐹 0.5 𝑉 𝑤 1.1 + 0.0156𝑉 𝑤 0.5 Wave Runup: 𝑅 = 𝐻𝑠 𝐴ξ𝑝 + 𝐶 𝛾𝑟𝛾𝑏𝛾ℎ𝛾𝛽
  • 23. Example of Freeboard Computations Fetch km ECRD CFRD ECRD CFRD <1.6 1.200 1.800 0.900 1.350 1.6 1.500 2.250 1.200 1.800 4 1.800 2.700 1.500 2.250 8 2.400 3.600 1.800 2.700 16 3.000 4.500 2.100 3.150 Freeboard for Preliminary Studies Reference: Normal Minimum Fell, et al. (2015) Fetch angle β RH 0 1 20 0.96 40 0.9 60 0.84 80 0.75 y = -2E-05x2 - 0.0017x + 0.9997 R² = 0.9988 0 0.5 1 1.5 0 20 40 60 80 100 Wave Height Reduction Factor, R H Angle of Main Radial with Normal to Dam Axis, β Wave height reduction due to angular spread Series1 Poly. (Series1) Detailed Freeboard Computations
  • 24. Riprap Upstream Slope Protection ◉ Median Weight: 𝑊50 = 𝛾𝑟𝐻3 𝐾𝑅𝑅 𝐺𝑠−1 3 cot 𝜃 ◉ Volume: W / ɣr ◉ Diameter: (V / 0.75)1/3 ◉ Thickness: 2D50 lbs kg ft3 m3 ft mm 100 1484 673 8.65 0.24 2.26 689 70 90 742 337 4.32 0.12 1.79 547 35 55 371 168 2.16 0.06 1.42 434 0 20 46 21 0.27 0.01 0.71 217 Wmax = 4 W50 0.5 Wmax W50 Wmin = W50 / 8 20% Band Riprap Specification % Finer Size Coarse Limit Fine Limit Weight Volume (W / ɣr) Diameter (V / 0.75)1/3 {H=H10=1.27Hs}
  • 25. Crest Width and typical details ◉ Crest Width is usually defined by practical considerations, like construction limitations, roadway requirements, seismically active areas, etc.; ◉ The smallest crest width, for small dams can be 3 – 4 m while for large dams it is 5 – 6 m. The crest width can also be approximated by means of empirical formulae, as a function of the dam’s height e.g.: 𝑏 = 3.6 3 𝐻 − 3. 𝑏 = 0.2𝐻 + 3. 𝑏 = 1 + 𝐴 𝐻 … (A=1.1 – 1.65)
  • 26. Camber Protection against overtopping ◉ CAMBER is provided along the crest of embankment dams, with the objective of ensuring that the crest elevation remains at or above the design crest elevation and that the freeboard will not be diminished after settlement. ◉ The most practical method of camber design is to apply the “1 percent rule”.
  • 27. Example of Camber Profile ◉ 1 % of the embankment height is calculated for various stations along the embankment. Then, the numbers are added to the post-construction foundation settlements to arrive at a required camber height.
  • 28. Example of Camber Profile 968.00 968.10 968.20 968.30 968.40 968.50 968.60 968.70 00+000 00+025 00+050 00+075 00+100 00+125 00+150 00+175 00+200 00+225 00+250 00+275 00+300 00+325 00+350 00+375 00+400 00+425 00+450 00+475 00+500 00+525 00+550 00+575 00+600 00+625 00+650 00+675 Dam Crest El. (m) Dam Centreline RD (m) Parabolic Camber Profile Linear Camber Profile Overall Camber Calculated ◉ The provided camber maintains incremental elevations across the embankment sections within the valley floor and is roughly proportional to the height of the embankment above its foundation.
  • 29. Embankment Dam Zones and Filters General Design Features of ECRD General Design Features of CFRD Seepage Control
  • 31. Schematic Presentation of a Filter (1) Basic material; (2) Filtering layers; (3) Drainage.
  • 33. 36" 24" 12" 9" 6" 4" 3" 2" 1½" 1" 3/4" 1/2" 3/8" #4 #8 #10 #16 #20 #30 #40 #50 #60 #100 #140 #200 0 10 20 30 40 50 60 70 80 90 100 0.001 0.01 0.1 1 10 100 1000 Percentage Passing Grain Size in Millimeters Sieve Size/No. Boulders Cobbles Gravel Coarse Sand Medium Sand Fine Sand Silt Clay Sample Filter Gradations ECRD CFRD Flow Chart for Base Soil Selection
  • 34. Conditions encountered in embankment dam zones and how they are protected by filters.
  • 35. Internal erosion and piping is ignored mainly because the main focus is usually the adequacy of the spillway and slope stability.
  • 36. Earth Core Rockfill Dam General Design Features of ECRD
  • 37. Typical ECRD Sections Zone Descriptions: 1 Impervious Core, 2A Fine Filter, 2B Coarse Filter, 2C Bedding, 3 Rockfill, 4 Riprap  Foundation cutoffs are to be tied up with bedrock for positive seepage cutoff expected through core trench at abutments and slurry trench wall in the riverbed reach.  Upstream impervious blanket is provided for lengthening the seepage path where depth to bedrock is unpractical.
  • 38. Typical Cutoff Wall Profile 0 50 100 Clamshell Backhoe 30 15 Excavation Depths (m) Extensive situations Less common Typical range Basic Types By Funtion Cutoff Barrier Diaphragm Wall By Composition Soil-Bentonite Cement-Bentonite Critical Criteria Permeability Permanence Deformability Strength
  • 39. Partial Cutoff Wall Cutoff Wall permeability Thickness of Cutoff Wall qf = rate of underseepage with foundation seepage control in m3 /sec d = penetration depth of cutoff wall in m W = open area in positive cutoff in m2 5 10 15 20 25 30 0.00E+00 1.00E-03 2.00E-03 3.00E-03 4.00E-03 5.00E-03 0 500 1000 1500 2000 2500 Rate of underseepage (qf), cumecs Lo = Discontinuous upstream impervious blanket length,meter 0.500 0.600 0.700 0.800 0.900 1.000 0 500 1000 1500 2000 2500 Flow Efficiency Lo = Discontinuous upstream impervious blanket length,meter Select L0 from table, assuming L3 = 0 450 10 h ZDesign 10% of head = 0.1h = 4.5 a. Corresponding L1 = = 402.7871752 8.95 h 750 16.67 h Z2 5% of head = 0.05h = 2.25 b. Corresponding 530.3300859 11.79 h Difference (b-a) = 127.543 2.83 h Zmin USBR (1987) Design of Small Dams 1.00 m c. Corresponding 353.5533906 7.86 h Selected upstream impervious blanket dimensions: Design thickness for blanket z bR = 0.1h = 4.5 m Effective length for z bR = ~ 9h = 405 m OK Half design thickness for blanket z 1 = 0.05h = 2.25 m Effective length (transition) for z 1 = ~ 3h = 135 m OK Minimum blanket thickness z min = 1 m Allowable effective length (remaining) for z min = ~ 8h = 360 m OK Provided discontinuous length L o = ~ 20h = 900 m OK ≈ ≈ Dam Crest Elevation 968 m Normal Conservation Level 961 m Riverbed Level 916 m Foundation permeability Kf = K˳= 2.50E-04 m/sec Core base width L2 = B = 25 m Head over foundation h= 45 m Depth of foundation D= (≈h) 50 m Initial Trial with No underseepage control Rate of underseepage Qo = = 2.25E-02 m3 /sec (Theoretical) Upstream Impervious Blanket Permeability of blanket KbR = 1.00E-07 m/sec Thickness of blanket zbR = 0.1 h 4.5 m Factor = 0.001333333 1/m Lo = discontinuous upstream impervious blanket length L1 = effective upstream impervious blanket length (Assuming L3 = 0) (m) (m3 /sec) 100 99.412 4.521E-03 0.799 200 195.390 2.552E-03 0.887 300 284.962 1.815E-03 0.919 400 365.944 1.439E-03 0.936 500 437.087 1.217E-03 0.946 600 498.028 1.075E-03 0.952 700 549.108 9.798E-04 0.956 800 591.152 9.129E-04 0.959 900 625.241 8.651E-04 0.962 1000 652.546 8.302E-04 0.963 1100 674.205 8.045E-04 0.964 1200 691.251 7.853E-04 0.965 1300 704.586 7.710E-04 0.966 1400 714.968 7.602E-04 0.966 1500 723.021 7.520E-04 0.967 1600 729.248 7.458E-04 0.967 1700 734.054 7.411E-04 0.967 1800 737.756 7.375E-04 0.967 1900 740.604 7.347E-04 0.967 2000 742.793 7.326E-04 0.967 Lo (m) USACE (1993). Seepage Analysis and Control for Dams , Engineer Manual 1110-2- 1901, Department of the Army, U.S. Army Corps of Engineers, Washington, DC, 30 April 1993. qf Thickness of blanket zbR = 0.1 h 4.5 m Factor = 0.001333333 1/m Lo = discontinuous upstream impervious blanket length L1 = effective upstream impervious blanket length (Assuming L3 = 0) (m) (m3 /sec) 100 99.412 4.521E-03 0.799 200 195.390 2.552E-03 0.887 300 284.962 1.815E-03 0.919 400 365.944 1.439E-03 0.936 500 437.087 1.217E-03 0.946 600 498.028 1.075E-03 0.952 700 549.108 9.798E-04 0.956 800 591.152 9.129E-04 0.959 900 625.241 8.651E-04 0.962 1000 652.546 8.302E-04 0.963 1100 674.205 8.045E-04 0.964 1200 691.251 7.853E-04 0.965 1300 704.586 7.710E-04 0.966 1400 714.968 7.602E-04 0.966 1500 723.021 7.520E-04 0.967 1600 729.248 7.458E-04 0.967 1700 734.054 7.411E-04 0.967 1800 737.756 7.375E-04 0.967 1900 740.604 7.347E-04 0.967 2000 742.793 7.326E-04 0.967 Lo (m) USACE (1993). Seepage Analysis and Control for Dams , Engineer Manual 1110-2- 1901, Department of the Army, U.S. Army Corps of Engineers, Washington, DC, 30 April 1993. qf
  • 40. Concrete Face Rockfill Dam (Face Slab connected with a Foundation Plinth) General Design Features of CFRD Zone Descriptions: 1A: Face protection zone, Joint or crack healer, cohesionless fine grained soil 1B: Random fill, support to 1A 2A: Perimeter filter zone, 2B: Face support zone, processed (-75mm particle size) 3A: Selected rockfill, (0.4m layers) 3B and 3C: Quarry run rockfill (1m and 2m layers).
  • 41. CFRD Design Elements Design of CFRD plinth includes dimensions for its thickness and width, followed by its geometric layout and alignment Where: A = Foundation Type B = Foundation Class C = Min. Ratio: Plinth Width/Water Depth (Full Reservoir) D = Rock Quality Designation (RQD in %) E = Weathering Degree: I = sound rock; VI = residual soil F = Consistency Degree: 1 = very hard rock; 6 = friable rock G = Weathered Macro Discontinuities per 10 m H = Excavation Classes: 1=requires blasting 2=requires heavy rippers; some blasting 3=can be excavated with light rippers 4=can be excavated with dozer blade Design of CFRD face slabs begins with the selection of slab thickness, width and location of vertical and horizontal joints. *H = Head of water above plinth in meters
  • 43. CFRD Plinth Alignment and Face Slab Layout Points Easting Northing Elevation ΔEl LPlan θ n h 1 315297.40 3351824.71 1832.5 35.5 60.71 41.25 2.27 0.92 2 315236.69 3351877.96 1797 0 55.00 0.00 0 1.00 3 315181.69 3351877.96 1797 -35.5 74.29 -35.63 -2.57 0.93 4 315107.40 3351824.71 1832.5 ∆𝐸𝑙 = 𝐸𝑙𝑖 − 𝐸𝑙𝑗 𝜃 = tan−1 ∆𝐸𝑙 × 𝑚 𝐿𝑝𝑙𝑎𝑛 𝑛 = 𝑚 sin 𝜃 ℎ = ℎ𝑜 1 + sin 𝜃 𝑚 2
  • 44. Geological Profile at Upstream Toe for Plinth Alignment
  • 46. CFRD Plinth Alignment and Face Slab Layout
  • 47. CFRD Plinth Alignment and Face Slab Layout
  • 48. Typical Plinth Geometry for Different Reaches
  • 50. Methods and Considerations Slope Stability Different shapes of sliding surfaces • Classical – Limit Equilibrium: Method of Slices • Advanced - FEM • Immediately following construction • Full reservoir with established stationary seepage flow • Rapid drawdown of water level
  • 51. Seepage and Stability Analysis – GeoStudio Results
  • 52. Seepage and Stability Analysis – Slide Results
  • 53. Reporting Stability Analysis Results Loading Conditions Critical Consideration Detailed Description Minimum FoS Required Analyzed Normal Long term seepage condition Downstream slope with steady state seepage from reservoir water level at 1139.5 m. amsl. 1.5 1.836 Unusual Short term seepage conditions Details as follows: Unusual-MSL Maximum surcharge pool Downstream slope with steady state seepage from reservoir water level at 1144.5 m. amsl. 1.4 1.836 Unusual-EoC End of Construction Upstream Slope 1.3 2.192 Downstream Slope 1.3 1.844 Unusual-RDD Rapid drawdown Upstream slope with transient seepage resulting from drawdown of reservoir from El. 1139.5 to El. 1126.5 (i.e. normal conservation to dead pool) 1.2 1.92 Unusual-OBE Operational Basis Earthquake (OBE) with normal loading condition Downstream slope with OBE seismic coefficients (0.18g) along with steady state seepage from reservoir water level at 1139.5 m. amsl. 1.1 1.311 Extreme-MCE Maximum Credible Earthquake (MCE) with normal loading condition Downstream slope with MCE seismic coefficients (0.32g) along with steady state seepage from reservoir water level at 1139.5 m. amsl. 1 1.083
  • 54. Reporting Stability Analysis Results Loading Condition Scenario Slope Face Slab Reservoir Level (m) Seismic Load Required FOS Calculated FOS Normal N1 SS DS Yes 1800 1.5 1.88 N2 EoC DS No 1.4 1.992 N3 EoC US No 1.4 1.547 Unusual U1 SS DS Yes 1802 OBE 1 1.063 U2 SS DS Yes 1800 DBE 1 1.172 U3a EoC DS No OBE 1 1.369 U3b EoC US No OBE 1 1.08 U4 EoC DS No 1800 1.2 1.426 U5a RDD DS No 1800- 1780 1.3 1.881 U5b RDD US No 1800- 1780 1.3 1.503 Extreme E1 SS DS Yes 1800 SEE 1 1.015 E2 EoC DS No 1800 OBE 1 1.011
  • 55. Typical Cut-Slope Analysis (SLIDE Results)
  • 58. Seismic Hazard Assessment Tectonic Feature Fault Type Maximum Magnitude (MW) Closest Distance to Fault (km) Peak Horizontal Ground Acceleration (g) Median Abrahamson-Silva NGA (2008) Boore-Atkinson NGA (2008) Campbell-Bozorgnia NGA (2008) Average PGA 50% 84% 50% 84% 50% 84% 50% 84% Chaman Fault (Naushki Segment) S 7.6 2 0.48 0.82 0.46 0.81 0.56 0.94 0.50 0.86 Ghazaband Fault S 7.6 25 0.15 0.26 0.18 0.32 0.17 0.29 0.17 0.29 PGA (g) OB RP (Yrs) Rock 0.19 145 0.16 0.28 475 0.25 0.36 1,000 0.32 0.49 3,000 0.44 0.67 10,000 0.61 MCE: 0.86g, SEE: 0.50g, OBE: 0.19g (OB), 0.16g (Rock), DBE: 0.28g (OB), 0.25g (Rock) Ref: ICOLD (2016) Bulletin No. 148. Results of Probabilistic Seismic Hazard Analysis Results of Deterministic Seismic Hazard Analysis
  • 61. Ortho-Image Grids for Dam Site Aerial Survey Quadcopter used for Aerial Mapping GCPs for Aerial Survey Satellite and Aerial Photogrammetry Digital Terrain Model (DTM) Topographic Survey Plan (at 1m contour interval)
  • 62. Comparative Survey Results 0 50 100 150 200 910 920 930 940 950 960 970 980 910 920 930 940 950 960 970 980 0 500 1000 1500 2000 Capacity (AF x 1000) Elevation (m amsl) Elevation (m amsl) Area (Acres) Reservoir Surface Area - Conventional Survey Reservoir Surface Area - Satellite DEM Reservoir Surface Area - Aerial Survey Reservoir Capacity - Conventional Survey Reservoir Capacity - Satellite DEM Reservoir Capacity - Aerial Survey Description (Unit) Conventional Survey Satellite Imagery DEM Aerial Survey Dead Storage (Aft) 25,800 25,474 (31.42 MCM) 25,952 (32.01 MCM) Gross Storage (Aft) 50,695 51,649 (63.71 MCM) 53,025 (65.41 MCM) Live Storage (Aft) 24,895 26,175 (32.29 MCM) 27,073 (33.40 MCM) Dead Storage El. (m amsl) 959 951 953 Gross Storage El. (m amsl) 970 961 963 Depth of Live Storage (m) 11 10 10
  • 63. Issues in dimensioning embankment dams, (a) and (c) are poor practice; (b) is the correct practice
  • 64. Some References of Interest Robin Fell, Patrick MacGregor, David Stapledon, Graeme Bell, & Mark Foster (2015). Geotechnical Engineering of Dams, 2nd Edition, CRC Press/Balkema, Leiden, Netherlands. ICOLD (2010). Concrete Face Rockfill Dams: Concepts for design and construction, International Commission on Large Dams, Bulletin 141. USACE (1993). Seepage Analysis and Control for Dams, Engineer Manual 1110-2-1901, Department of the Army, U.S. Army Corps of Engineers, Washington, DC, 30 April 1993. USBR (2011). Design Standard No. 13: Embankment Dams. Chapter 5: Protective Filters, Revision 9, Phase 4 (Final). November 2011, United States Bureau of Reclamation [DS-13(5)-9]. USBR (2012). Design Standards No. 13: Embankment Dams, Chapter 6: Freeboard, Revision 2, Phase 4 (Final), September 2012, United States Bureau of Reclamation [DS-13(6)-2]. USBR (2014). Design Standards No. 13: Embankment Dams, Chapter 7: Riprap Slope Protection, Revision 2.1, Phase 4 (Final), May 2014, United States Bureau of Reclamation [DS-13(7)-2.1]. USBR (2014). Design Standards No. 13: Embankment Dams, Chapter 8: Seepage, Revision 4.1, Phase 4 (Final), January 2014, United States Bureau of Reclamation [DS-13(8)-4.1].
  • 65. Any questions ? You can contact me at ◉ zaheer.malik@pespk.com Thanks!