Concrete Dam Stability Checks

Hydro Power and Pump Storage in the Black Forest 2013

Company: T5

Study case staff:

Amirpasha MozaffariDaniel de Souza Braga

Irfan MahmoodJuliana Zapata Giraldo

Mingze Xu

Introduction

1) Dam Design Parameters

2) Drawings of Critical Cross section &Site Plane.

3) Stability Proofs4) Stability Proof

without Water5) Continuation to

Design Flood & Hydraulic Dimensioning

Atlas Reservoir

1150 mAt

las R

eser

voir

670 m

L.M

.P.R

625 m

Hydr

o-Po

wer

Hydropower Plant (UHP)

DHP Toe

400 m

350 m

DHP 2

DHP 1

Low Multi Purpose Reservoir ( L.M.P.R)

Part 1

Introduction






Part 2: Design of Concrete Gravity Dam Topic 2a: Hydraulics • 2.1 Determination of dam-design parameters

such as dam height and length, shape of longitudinal dam-axis, dam-slopes, construction material and foundation depth

• 2.2 Drawings of critical cross section and site plan

• 2.3 Structural investigations such as stability proofs (traditional methods; FEM analysis not required but welcome)

Topic 2b: Structure (My colleague Xu Mingze)

My Task



3) Stability Proof4) Stability Proof



Parameters

a = 46 m (Height from given levels)

b = 57 m (Width)

c = 5 m (Service Road)

x = 0.788 (chosen from 0.7 – 0.8)

y = 1

L = 400 m

Parameters

Dead Load KN/mWeight 1 (rectangle vertical dam) 5076.675Weight 2 (rectangle foundation) 7548.795Weight 3 (triangle) 23529.285Total Dead Load 36154.755






Water Pressure

Dead Loads

Water Pressure KN/mHorizontal 12757.905Vertical 0Uplift 8806.9275

Loads

Cross-Section

1) Dam Design

Parameters 2) Drawings of

Critical Cross section &Site Plane

3) Stability Proofs4) FEM Results5) Continuation to


Max. Operation Level: 670 m Freebord: 1 m Lowest Point Dam: 625 m

Foundation Level: 619 m

Site Plan


2) Drawings of Critical Cross section &Site Plane









Concrete Properties (A)

-Density: 2.25 g/cm3 = 2250 kg/m3

-Angle of internal friction (φ ): 43.5 º

-Compressive strength: 15.8 N/mm2 = 161 kg/cm2

-Tensile strength: 1.9 N/mm2 = 19.37 kg/cm2

-Degree of join: 0.01

Rock Foundation Properties (A)

-Density: 2.64 g/cm3 = 2640 kg/m3

-Angle of internal friction (φ ): 52.5 º

-Compressive strength: 111.3 N/mm2 = 1134.5 kg/cm2

-Tensile strength: 10 N/mm2 = 101.94 kg/cm2

-Degree of join: 0.03

Given Values

Dimensioning Situations

Overall Safety Factors1) Dam Design

Parameters 2) Drawings of

Critical Cross section &Site Plane









Load Case I

Resistance Conditions of Structure = Likely Loadings

Dimensioning Situation = BS I






SAFETY AGAINST FLOATING

Force/Load Description Fi (kN)Uplift 8806.928

8806.928

Force/Load Description Fi (kN)Vertical Water Load 0Dead Load 36154.755

36154.76

ηa = 4.11 > 2 4.11

Safety Against Floating






SAFETY AGAINST SLIDING

Force/Load Description Fi (kN)Horizontal Water Load 12757.905

Fo 12757.91kN

Force/Load Description Fi (kN)Vertical Water Load (Fw,v,i) 0Dead Load (Gi) 36154.755Uplift (Fup) -8806.928

27347.83tan φ' 1.303

Fr 35640.38kNDegree of Joint (a) 0.25Shear Force of Rock ( c) 22700 kN/mArea of foundation (A) 57.0 m2/m

Frt 359115.4

ηg = 28.15 > 1.5 28.15

Safety Against Sliding






SAFETY AGAINST OVERTURNING

Force/Load Description Fi (kN) di (m) Fi*di (kN.m)Horizontal Water Load 12757.905 0

1 (triangle water) 12757.905 17 -216884.385Uplift 8806.928 38 -334663.245

Mo -551547.63

Force/Load Description Fi (kN) di (m) Fi*di (kN.m)Vertical Water Load 0 0 0Weight 1 5076.675 54.5 276678.7875Weight 2 7548.795 28.5 215140.6575Weight 3 23529.285 34.6666667 815681.88

Mr 1307501.325

ηo = 2.37 > 1.5 2.37

Resultant Turning Moment, M'r 755953.695kN.mVerticalResultant, Rv 27347.828kNDistance X 27.642mExcentricity 0.858m 27.64218456

Stress at head water side, σh 436.463kN/m2Stress at tail water side, σt 523.109kN/m2

Fb/3 X 2/3 Fb19 < 27.640 < 38 27.64

e = 0.86 < 9.5 (Fb/6) 0.86

Safety Against Overturning


2) Drawings of Critical Cross section &Site Plane II




SAFETY AGAINST ADMISSIBLE BASE PRESSURE

Stress at head water side, σh 436.463476kN/m2

Stress at tail water side, σt 523.109418kN/m2

Admissible Base Pressur, σa 1000kN/m2

σt,h = 523.11 < 1000 523.1094183

Admissible Pressure






SAFETY AGAINST ADMISSIBLE BASE PRESSURE

Stress at head water side, σh 122.584238kN/m2Stress at tail water side, σt 1146.00366kN/m2

Admissible Base Pressur, σa 1000kN/m2

σt,h = 1000< 1146.01 < 4000 1146.003657

Admissible Pressure w/o water

THANKYOU

QUESTIONS ?






Concrete Dam Stability Checks

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