Dam Safety Instrumentation with Case Study · Dam Safety Instrumentation with Case Study Dr. Rajbal...

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Dam Safety Instrumentation with Case Study Dr. Rajbal Singh Joint Director Rock Mechanics Discipline Central Soil and Materials Research Station (CSMRS), New Delhi

Transcript of Dam Safety Instrumentation with Case Study · Dam Safety Instrumentation with Case Study Dr. Rajbal...

Dam Safety Instrumentation with Case Study

Dr. Rajbal SinghJoint Director

Rock Mechanics DisciplineCentral Soil and Materials

Research Station (CSMRS), New Delhi

Dam Instrumentation

• Safety of Dam• Construction• First Filling• Operation

• Refinement of Design• Back Analysis

Status of Dam Instrumentation in India

• 4800 Dams + 475 under construction• 200 Instrumented Dam (< 5 %)• About 50 years ago, instruments were not

usually specified in Water ResourcesProject Proposals and instruments wereinstalled only when problems wereencountered during construction andoperation of the project.

• Instrumentation is generally specified ineach Project Proposal: Tala, Tehri, NJP,SSP, Indira Sagar.

TO THIMPHU

DAMPOWER HOUSE

TAIL RACE TUNNELKM 7.5

ROAD TO MIRICHINGCHU ADIT NO. 4

ROAD TO POWER HOUSE

ADIT NO.5

ADIT NO.3

ADIT NO.2

ADIT NO.1

ADIT NO.4

HEAD RACE TUNNEL

KM 45

ROAD TO GEDUCHUADIT NO. 3

ROAD TO PADECHUADIT NO. 2

ROAD TO DAM SITE & ADIT NO. 1

KM 80 P.T. ROAD

89O 40' 89O 40'

R OAD TO KALIKHOLAADIT NO. 5

TO PHUENTSHOLING

C1

C2

C3

C4

C5

MONITAR

Tala Hydroelectric Project, Bhutan

Layout of Head Race Tunnel

RD 0RD 3456

RD 9399

RD 13355

RD 18094

RD 21470

RD 23032

Thiyomachu (101m)

Padechu (268m)

Geduchu (963m) Mirchingchu

(320m)

Kalikhola (520m)

C1 C2 C3 C4 C5

HRT 6.483 km HRT 4.997 km HRT 4.400 km HRT 7.183 km

D/s - 3027mU/s - 1212m

D/s - 2081mU/s - 2916m

D/s - 2525mU/s - 1875m

Mirchingchu Kalikhola

Thiyomachu

TakctchuD/s – 2244m

Dam Complex Powerhouse

Complex

D/s - 2201mU/s - 2214m

D/s – 1592.6mU/s - 1175m

Excavation of HRT from 11 Faces

AGO Reach

By Pass of HRT

PROJECT FEATURESDam on River Wangchu

Concrete Dam - 92 m height 130 m length (Located 3 km d/s of Chukha Power House)Diversion Tunnel - 6.8 m diameter 356 m length

U/S View of DamIntake Structures

Coffer DamDiversion Tunnel

Dam D/S with Sluices Glacis (HPC)

During Construction During Operation

Dam U/S & D/S during Operation

Instrumentation Programme at THEP

•Planning•Technical Specifications•Contractual Arrangement

•Calibration of Instruments•Supply•Installation•Monitoring

Instrumentation Programme at THEP

• Accuracy of Data• Analysis• Documentation/Report• DAS• Attitude/Interest of Project

Management• Instrumentation Responsibility• Cost of Instrumentation [3%]

Cost and Power Generation

• Cost to Completion – Rs. 43210 million• Project Fully financed by the Govt. of India• Indian Technology• Instrumentation Cost

• Annual Generation - 4865 million units• Cost per unit - Rs. 1.80 per unit (India)

- Rs. 0.30 per unit (Bhutan)

Instrumentation at Tala ProjectQuality Control and Instrumentation• Contractual Arrangements

– EnCardio Rite Electronics Ltd., Lucknow

• Calibration of Instruments• Supply• Installation• Monitoring • Reporting of Monitoring

• Documentation

RemarksInstalledProposed

Monitoring22Automatic Water Level Recorder

11

Monitoring44Strong Motion Accelerograph10Monitoring2020Up Lift Pressure Pipe9

Monitoring12621 Sets

12621 Sets

Vibrating Wire Strain Meter8Monitoring2121Concrete Pressure Cell7

Monitoring11Inverted Plumb Line6

Monitoring22Normal Plumb Line5Monitoring79MPBX4Monitoring1823Joint Meter/ Crack Meter3Monitoring3037Pore Pressure Meter2Monitoring5151Temperature Meter1

Total No. of InstrumentsName of InstrumentS.No

Instruments Installed in Dam

Instruments Installed in Dam

• Instruments Installed = 282 Nos.

• Instruments Working = 277 Nos.

• Instruments Not Working = 5 NOs.

2 3 4 5 6 71

U/S View of Dam, Intake Structures Coffer Dam, Diversion Tunnel

TYPE: CONCRETE GRAVITYHEIGHT: 92 MNO. OF BLOCKS: 7UNDERSLUICES: 5OVER SPILLWAY: 1

LOCATIONS OF INSTRUMENTS IN DAM BLOCK 2

Concrete Placement in Tala DamConcrete Completed- March 2006

EL. 1354.50

ELEVATOR SHAFT2500X2400

1NO. OVERFLOW SPILLWAY1000 PARAPET

7

EL. 1338.50

EL. 1310.50

EL. 1354.502000

EL. 1320.00

EL. 1309.50

EL. 1306.50

EL. 1280.50

FOUNDATION GALLERY

CROSS

7000

5250

EL. 1306.50

5 NOS.

(6500 X 13150)

EL. 1283.50EL. 1281.50

SUMP WELL EL. 1277.50

3 5 6 74

EL. 1296.50

GALLERY

EL.1366.00

EL. 1340.50

EL.1367.00 EL.1366.00

12 SLUICE

SPILLWAY

LOCATIONS OF INSTRUMENTS IN DAM BLOCK 5

OBSERVATION OF TEMPERATURE METERS

15

20

25

30

351/

3/20

01

1/4/

2001

5/5/

2001

17/1

1/01

1/1/

2002

1/2/

2002

7/3/

2002

2/4/

2002

29/1

1/02

7/1/

2003

9/2/

2003

9/3/

2003

10/4

/200

3

9/5/

2003

Date

Tem

pera

ture

(o C)

B2T2 B2T3 B5T3 B5T7 B5T8

30.90C

220C

OBSERVATION OF TEMPERATURE METERS

TEMPERATURE METER BLOCK 5

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

DATE Figure 6A: Observation of Temperature meters B5T16 to B5T22

B5T16 B5T17 B5T18 B5T19 B5T20 B5T21 B5T22

16.1

OBSERVATION OF TEMPERATURE METERS

New Temperature M eters Of Block-2

0.01.02.03.04.05.06.07.08.09.0

10.011.012.013.014.015.0

DATE Figure 5B : Observat ion of Temperat ure Met ers B2T19 t o B2T24

B2T19 B2T20 B2T21 B2T22 B2T23 B2T24

Temperature Meters in Block 2

22.6

30.9

19.0

10.3

16.8

9.0

6

11

16

21

26

31

03/0

1/20

01

06/0

4/20

01

23/0

5/20

01

25/1

2/20

01

02/0

1/20

02

16/0

3/20

02

16/0

4/20

02

01/0

1/20

03

09/0

2/20

03

16/0

3/20

03

24/0

4/20

03

26/0

1/20

04

27/0

2/20

04

06/0

4/20

04

12/0

5/20

04

11/0

9/20

04

21/1

0/20

04

04/1

2/20

04

11/0

1/20

05

23/0

2/20

05

06/0

4/20

05

09/0

5/20

05

28/0

6/20

05

22/0

8/20

05

28/0

9/20

05

02/1

1/20

05

05/1

2/20

05

11/0

1/20

06

Monitoring Time (Date)

Tem

prat

ure

(deg

ree

c)

B2T1 B2T2 B2T3 B2T4 B2T5 B2T6B2T7 B2T8 B2T9 B2T10 B2T11 B2T12B2T13 B2T14 B2T15 B2T16 B2T17 B2T18B2T19 B2T20 B2T21 B2T22 B2T23 B2T24B2T25 B2T26 B2T27 B2T28 B2T29

Cement Content & Concrete Temperature

Cement Content kg/m3

Temperature of Mass Concrete

Remarks

210 25.4 (10-30.9) Cracking

200 22.5 (10-28.8) Cracking

190 19.0 (10-27.7) Cracking

180 14.9 (10-15.6) No Cracking

170 14.3 (10-14.3) No Cracking

160 13.6 (10-13.6) No Cracking

140 12.4 (10-5.2-12.4) No Cracking

Strength of In-situ Cores with Age and Cement Content

25.41 27.18

43.77 42.82

33.58

21.18

90

362410

467

750

1016

0

10

20

30

40

50

60

160 170 180 190 200 210Cement Content, Kg/m3

Com

pres

sive

Stre

ngth

, MPa

0

200

400

600

800

1000

1200

Test

ing

Age

, day

s

Compressive Strength Testing Age

Cube Compressive Strength at Different Testing Age

13.95

20.73

23.925.33

27.12

11.43

20.33

25.44

28.67

31.46

6.28

14.48

22.90

26.83

28.35

6.04

14.83

21.41

29.45 29.71

7.35

17.42

24.45

0

5

10

15

20

25

30

35

7 28 90 180 365Testing Age (Days)

Com

pres

sive

Str

engt

h (M

Pa)

Cement Content = 200 kg/m3Cement Content = 190 kg/m3Cement Content = 180 kg/m3Cement Content = 170 kg/m3Cement Content = 160 kg/m3Comp. Strength = 15 MPa after 365 daysComp. Strength = 12.5 MPa after 28 days

Pore Pressure Meters in Block 5

5.6

2.8

3.8

2.321.8

1.3

3.6

2.5

4.0

0.0

1.0

2.0

3.0

4.0

5.0

6.0

15/0

3/20

01

26/0

4/20

01

17/1

1/20

01

01/0

9/20

02

17/0

2/20

02

30/0

3/20

02

29/1

1/20

02

16/0

1/20

03

27/0

2/20

03

04/0

4/20

03

05/0

9/20

03

26/1

0/20

03

26/0

1/20

04

27/0

2/20

04

04/0

6/20

04

05/1

2/20

04

09/1

1/20

04

21/1

0/20

04

12/0

4/20

04

01/1

1/20

05

19/0

2/20

05

28/0

3/20

05

06/0

5/20

05

16/0

6/20

05

10/0

8/20

05

22/0

9/20

05

26/1

0/20

05

03/1

2/20

05

05/0

1/20

06

Monitoring Time (Date)

Pore

Pre

ssur

e (k

g/cm

2)

B5P1 B5P2 B5P3 B5P4 B5P5 B5P6

B5P7 B5P8 B5P9 B5P10 B5P11 B5P12

B5P13 B5P14 B5P15 B5P16

Stress Meters in Block 2

5.5

4.74.2

1.0

0

1

2

3

4

5

6

03/0

1/20

01

26/0

4/20

01

14/1

2/20

01

09/0

2/20

02

02/0

4/20

02

01/0

1/20

03

27/0

2/20

03

16/0

4/20

03

24/0

6/20

03

17/0

7/20

03

31/0

8/20

03

21/1

0/20

03

11/1

2/20

03

26/0

1/20

04

10/0

3/20

04

05/0

5/20

04

23/0

9/20

04

17/1

1/20

04

11/0

1/20

05

03/0

5/20

05

25/0

4/20

05

28/6

/200

5

05/0

9/20

05

26/1

0/20

05

12/1

2/20

05

Monitoring Time (Date)

Stre

ss (k

g/cm

2)

B2S1 B2S2 B2S3 B2S4 B2S5

B2S6 B2S7 B2S8 B2S9 B2S10

Strain Meters in Dam Block 2

-30.0

-20.0

-10.0

0.0

10.0

20.0

30.0

40.0

11/0

2/20

04

10/0

3/20

04

19/0

4/20

04

24/0

5/20

04

01/1

0/20

04

14/1

1/20

04

18/1

2/20

04

25/0

1/20

05

23/0

2/20

05

04/0

6/20

05

05/0

9/20

05

28/0

6/20

05

22/0

8/20

05

28/0

9/20

05

02/1

1/20

05

05/1

2/20

05

11/0

1/20

06

Monitoring Time (Date)

Stra

in (m

icro

met

er)

B2SN9A B2SN9B B2SN9CB2SN9D B2SN9E B2SN9F

Report on Instrumentation Monitoring

Report on Reprt # 6Quality Control and Instrumentation for

Concrete Gravity Dam of 1020 MW Tala Hydroelectric Project in Bhutan

Volume II: Instrumentation

Dr. Rajbal SinghChief Research Officer, Quality Control

Engineer-In-Charge, InstrumentationQuality Control Department

Tala Hydroelectric Project AuthorityGedu, BhutanOctober 2006

INDEXS. NO. CONTENTS PAGE NO.

PREFACE ILIST OF TABLES v-vi

LIST OF FIGURES vii-viii

1.0 INTRODUCTION 12.0 DETAILS OF INSTRUMENTS 23.0 INSTALLATION OF INSTRUMENTS 74.0 MONITORING OF INSTRUMENTS 95.0 CONCLUSIONS 17

ACKNOWLEDGEMENTS 18REFERENCES 19TABLES 21-166FIGURES 167-213ANNEXURES 214-235

CONCLUSIONS Mass concrete temperature, which was about 100C

at the time of placement, has risen up to 30.90Cand finally settled down between 21.60C to 22.50C.

Due to low ambient temperature (40C) in the monthof January, temperature of mass concrete droppedduring 3 days from 9.90C to 5.20C and increasedagain up to 12.60C.

• Cement content in mass concrete should beoptimized to achieve required strength. Highcement content leads to cracking in massconcrete.

• Temperature readings should be monitored fromthe time of placement of concrete.

• Instrument should be calibrated with placementtemperature of mass concrete.

CONCLUSIONS … contd.

The pore pressure meters installed haveshown pore pressures in the range of 3.2kg/cm2 to 4.0 kg/cm2, in Blocks 2 and 5respectively.

Three joint meters/crack meters installed inblocks 3 and 5 at the cracks, show theincrease in crack width in the order of 0.01mmto 0.11 mm.

The joint meters installed between two blocksjoint have shown insignificant displacement inthe range of 0.01mm to 5.40mm.

CONCLUSIONS … contd. The concrete pressure cells installed in Blocks 2

and 5 have shown pressures in the massconcrete varying from 5.5 kg/cm2 to 4.4 kg/cm2

which is 3.8 to 4.76 time lower than theoreticallyexpected stresses of 20.16 kg/cm2 and 20.95kg/cm2 based on mass concrete density of 2400kg/cm2 and height of blocks 84 m and 87.30 mabove the pressure cells, respectively. However,the pressure cells have shown increasing trendduring observations.

9.2 kg/cm2 & 12.6 kg/cm2 from FEM The safe design parameters must be made

available and may be attached with dataacquisition system as alarm for furthermonitoring the safety of dam.

CONCLUSIONS …contd.In general, behaviour of all instruments installed in Tala dam was in order with respect to increasing/decreasing trends in observations.

A record number of 277 instruments were in working order out of 282.

This was possible due to awarding a contract for supply, installation, maintenance and monitoring of instruments before commencement of dam construction.

Temperature Meter

Pore Pressure Meter Joint Meter/Crack Meter

Instruments InstalledConcrete Pressure Cell

Strain MeterSpider For Strain Rosettes

MPBX

MULTI POSITION BOREHOLE EXTENSOMETER (MPBX)

Instruments Installed

READ-OUT UNIT/DATALOGGER

NORMAL & INVERTED PLUMBLINES

INSTRUMENTS INSTALLED

• Uplift pressure Meters

• Water Level Indicators

• Surveying Points or Targets

INSTRUMENTS INSTALLEDSEISMOGRAPH

STRONG MOTION ACCELEROMETER

GPS

SAM

INCLINOMETER SYSTEM

CASING

PROBE

CONNECTING CABLE REEL

INCLINOMETER DATALOGGER

SETTLEMENT MAGNETIC SYST EM

MAGNETIC PROBE

DISC/PLATE MAGNET

SPIDER MAGNET

Thank You

For your

Kind

Attention Please