26 June 2012

26 June 2012

Korea Rural Research Institute

Gun Heo

Piezometer Installation

IntroductionII

ConclusionsVV

ContentsContents

In-situ ExperimentsIIII

Results and Discussion

IIIIII

IVIV

- Borehole Image Processing System (BIPS)

- In-Situ permeability test

Background & PurposeBackground & Purpose

• Seawater Blocking

• Securing fresh water

• Development Internal

Purpose of Seadike

• The riprap-bottom layer connects

both

seaside and lakeside, so permeable

• Reclaimed with dredged sands

Construction Condition ofthe Final Closing Section

• Piping and Erosion Embankment

• Desalination delay due to

excessive infiltration

were Concerned

Evaluate the status of riprap layer

Establish a long-term monitoring plan

Evaluate the status of riprap layer

Establish a long-term monitoring plan

Determine whether need reinforcement

Effective Safety management seadike

Determine whether need reinforcement

Effective Safety management seadike

Dredged SandsDredged Sands

Riprap Bottom LayerRiprap Bottom Layer

Outline

To evaluate the Filling Status

Filling Status

To evaluate the Permeation

Permeation

To measure the Pore Pressure

Installation PiezometerItems

Borehole Image Processing System (BIPS)

In-situ Permeability test Installation Piezometers and Building Monitoring System(Automated)

Visually check the Filling Status of the Bottom Layer.

Comparison the degree of

permeability

(General / Final closing)

Long-term Monitoring ⇒ Evaluate the temporal variation of Filling Status ⇒Propose Criteria for Monitoring

Purpose

Detailed Task

Utilization

• Determine whether need

reinforcement

• Safety Management

• Determine whether need

reinforcement

• Safety Management

Field test results + Data measured

• Evaluated Current state of the filling

& temporal variation of Filling Status

• Proposed Criteria for Monitoring

Bottom Protection Layer of the Final Closing SectionBottom Protection Layer of the Final Closing Section

< General Section > < Final Closing Section L = 1.8 km > < General Section>

To find the most vulnerable sections…

Electrical Resistivity ResultsElectrical Resistivity Results

electrical resistivity results of No. 59+60~No. 62+35 (5m electrode gap)electrical resistivity results of No. 59+60~No. 62+35 (5m electrode gap)

BelowBelow

Above Above

No. 60+25 Relatively low resistivity and showing the continuity sections No. 60+25 Relatively low resistivity and showing the continuity sections

Selected Sections(3 Final Closing Sections, 1 General Section)Selected Sections(3 Final Closing Sections, 1 General Section)

<Final Closing> No. 60 + 25



<General> No. 82 + 00

BIPS (Borehole Image Processing System)BIPS (Borehole Image Processing System)

BIPSBIPS

• To decipher the filling degree of the bottom layer

No of

HallsLocation Focused

4Near the

PiezometerRiprap

Bottom Layer

•Top (13.9m)

•Dredged Sands

•Riprap

• Riprap

• Dredged Sands

• Bottom (17.1m)

Results

In-situ Permeability testIn-situ Permeability test

Permeability TestPermeability Test ResultsResults

To compare the differences in permeability coefficients Number Location Test Section

Permeability

Coefficient k(cm/s)Remarks

BH-1 60+25Embankment 1.48×10-3

Final Closing Section

Bottom Layer 3.25×10-3






General SectionBottom Layer 9.17×10-4

<Embankment/Bottom Layer> <General/Final Closing>

The differences are not significant

No of

HallsLocation Focused

4Near the

PiezometerRiprap Bottom

Layer

Casing

Installation PiezometersInstallation Piezometers

10

PiezometerPiezometer Cross-SectionalCross-Sectional

I General Section

3 Final Sections

Location

Piezometer

Items

• Automated measurement system

has been built for four-sections

• By measuring the pore pressure,

Compare those between general

section and Final closing sections,

evaluate the filling status of the

bottom layer

• In addition, by conducting long-term

monitoring , evaluate the safety of

seadike with hydraulic head loss ratio

• Arranged piezometers to compare the pore pressure of each

section

(between the final closing section and normal section)

• Arranged piezometers to compare the pore pressure of each point

• (between P1 and P3, P3 and P7)

• 4 piezometers in bottom protection layer (P-1,3,5,7)

• 4 piezometers in embankment (P-2,4,6,8)

CL

18.60

4.50

14.10

18.50

4.00

14.50

13.60

5.00

8.60

13.00

4.00

9.00

21.20

4.50

16.70

15.00

5.00

10.00

CLCL

CLCL

20.00 20.00 21.50

16.40

5.10

9.07

4.70

13.80P- 2

EL(+)5.25EL(+)3.88

EL(-)10.06

EL(-)5.56

EL(-)8.86

EL(-)10.64

EL(-)5.54

EL(-)9.14 EL(-)9.75 EL(-)9.89

EL(-)4.75 EL(-)5.19

EL(+)11.18 EL(+)10.91

EL(+)5.47EL(+)3.73

EL(-)7.42 EL(-)7.59EL(-)8.13 EL(-)9.27

EL(-)2.92 EL(-)3.59 EL(-)3.13

EL(-)5.27

W- 1 W- 2

P- 1P- 3

P- 3

P- 4

P- 4

P- 5

P- 5

P- 6

P- 6

P- 7

P- 7

P- 8

P- 8

P- 1

P- 2

Monitoring ProgramMonitoring Program

방조제평면도

상단메뉴

계측단면도

최근계측데이터실시간표시

수두손실율그래프 간극수압그래프

경고표출범례

범례 및계측요약

Floor plan

Menu Bar

Cross-section

Hydraulic Head Loss Ratio Pore pressure

Legend

Measured Value

간극수압

(kg

/)

간극

수압

㎠

0.0

0.2

0.4

0.6

0.8

1.0

2011-09-10 2011-09-17 2011-09-24 2011-10-01 2011-10-08 2011-10-15

간극수압

(kg

/)

간극

수압

㎠

0.0

0.2

0.4

0.6

0.8

1.0

2011-09-10 2011-09-17 2011-09-24 2011-10-01 2011-10-08 2011-10-15

간극수압

(kg

/)

간극

수압

㎠

0.0

0.2

0.4

0.6

0.8

1.0

2011-09-10 2011-09-17 2011-09-24 2011-10-01 2011-10-08 2011-10-15

간극수압

(kg

/)

간극

수압

㎠

0.0

0.2

0.4

0.6

0.8

1.0

2011-09-10 2011-09-17 2011-09-24 2011-10-01 2011-10-08 2011-10-15

센서 측정 테스트

Measurement Results No.60+25(Final Closing section)Measurement Results No.60+25(Final Closing section)

P1P1 P3P3

P5P5 P7P7

• Pore pressure changes due to tidal fluctuations that are quite stable

• From sea side to the lake side, the changes in pore pressure gradually decreases

Time(day) Time(day)

Time(day) Time(day)

간극수압

(kg

/)

간극

수압

㎠

0.0

0.2

0.4

0.6

0.8

1.0

2011-09-10 2011-09-17 2011-09-24 2011-10-01 2011-10-08 2011-10-15

간극수압

(kg

/)

간극

수압

㎠

0.0

0.3

0.6

0.9

1.2

1.5

2011-09-10 2011-09-17 2011-09-24 2011-10-01 2011-10-08 2011-10-15

간극수압

(kg

/)

간극

수압

㎠

0.0

0.3

0.6

0.9

1.2

1.5

2011-09-10 2011-09-17 2011-09-24 2011-10-01 2011-10-08 2011-10-15

간극수압

(kg

/)

간극

수압

㎠

0.0

0.3

0.6

0.9

1.2

1.5

2011-09-10 2011-09-17 2011-09-24 2011-10-01 2011-10-08 2011-10-15


P1P1 P3P3

P5P5 P7P7

• Pore pressure changes due to tidal fluctuations that are stable

• From the sea side to the lake side, the changes in pore pressure gradually decreases

Time(day) Time(day)

Time(day) Time(day)

간극수압

(kg

/)

간극

수압

㎠

0.0

0.2

0.4

0.6

0.8

1.0

2011-09-10 2011-09-17 2011-09-24 2011-10-01 2011-10-08 2011-10-15

간극수압

(kg

/)

간극

수압

㎠

0.0

0.3

0.6

0.9

1.2

1.5

2011-09-10 2011-09-17 2011-09-24 2011-10-01 2011-10-08 2011-10-15

간극수압

(kg

/)

간극

수압

㎠

0.0

0.3

0.6

0.9

1.2

1.5

2011-09-10 2011-09-17 2011-09-24 2011-10-01 2011-10-08 2011-10-15

간극수압

(kg

/)

간극

수압

㎠

0.0

0.3

0.6

0.9

1.2

1.5

2011-09-10 2011-09-17 2011-09-24 2011-10-01 2011-10-08 2011-10-15


P1P1 P3P3

P5P5 P7P7



Time(day) Time(day)

Time(day) Time(day)

간극수압

(kg

/)

간극

수압

㎠

0.0

0.2

0.4

0.6

0.8

1.0

2011-09-10 2011-09-17 2011-09-24 2011-10-01 2011-10-08 2011-10-15

간극수압

(kg

/)

간극

수압

㎠

0.0

0.2

0.4

0.6

0.8

1.0

2011-09-10 2011-09-17 2011-09-24 2011-10-01 2011-10-08 2011-10-15

간극수압

(kg

/)

간극

수압

㎠

0.0

0.3

0.6

0.9

1.2

1.5

2011-09-10 2011-09-17 2011-09-24 2011-10-01 2011-10-08 2011-10-15

간극수압

(kg

/)

간극

수압

㎠

0.0

0.3

0.6

0.9

1.2

1.5

2011-09-10 2011-09-17 2011-09-24 2011-10-01 2011-10-08 2011-10-15

Measurement Results No.82+00(General section)Measurement Results No.82+00(General section)

P1P1 P3P3

P5P5 P7P7



• General section shows a smaller value than final closing section.

Time(day) Time(day)

Time(day) Time(day)

Building Monitoring SystemBuilding Monitoring System

• Installation Piezometer

- 3 on the final closing sections(No.60+25, No.65+00, No.69+80)

- 1 on the general section(No.82+00)

- 8 Piezometers are installed on each section

• Monitoring Program

- Express the results and Monitor for long-term

• Installation Piezometer

- 3 on the final closing sections(No.60+25, No.65+00, No.69+80)

- 1 on the general section(No.82+00)

- 8 Piezometers are installed on each section

• Monitoring Program

- Express the results and Monitor for long-term

SummarySummary

• Every piezometer is operating properly

• Reliable pore pressure data are being collected

• Sea-side : Large Fluctuation, Lake-side : Small Fluctuation


• Reliable pore pressure data are being collected

• Sea-side : Large Fluctuation, Lake-side : Small Fluctuation

Hydraulic Head Loss RatioHydraulic Head Loss Ratio

Hydraulic Head Loss RatioHydraulic Head Loss RatioTide/Pore pressure HeadTide/Pore pressure Head

1

21

P

PP

H

HHa

• a : Hydraulic Head Loss Ratio

• ΔHp1,2 : changes of pore pressure head at P1, P2

• “a” has the value of 0~1

• when a=0, ΔHp1 = ΔHp2,

• a=1, ΔHp2 = 0 ← NOT affected by tide at all

P1=tide level EL(m)

P1

-P2

EL(

m)

R2=Coefficient of determination

• The value of 0~1

• Closer to 0, Unstable

• Closer to 1, stable

Time (day)

Tide (m)Pore pressure head (m)

• Overlapped two graphs.

• Gray : tide level

• Black : Pore pressure Head of somewhere inside the structure which is affected by tide

• but, depends on the position and the time, the ranges of pore pressure will be changed

• Hard to set a criteria

Criteria(?)Criteria(?)

P1 P2

해측

내측내측제체

Sea-side

inner-sideembankment



Changes of TrendsChanges of Trends

Upward(Enlarged Head Difference)

Downward(Lessened Head Difference)

degree of dispersion(Change of the Infiltration Path)

Changes of inclination

Evaluation by Hydraulic Head Loss Ratio (No.60+25)Evaluation by Hydraulic Head Loss Ratio (No.60+25)

Bottom Protection LayerBottom Protection Layer EmbankmentEmbankment

• At P1, a = 0.228 R2= 0.931,

Blocking the water looks worse,

but the behavior is stable

• At P7, a = 0.972 R2= 0.997

Closer to the Lake-side, values

getting higher

•At P2, a = 0.289 R2= 0.935,



• At P8, a = 0.972 R2= 0.993

Closer to Lake-side, a value

becomes higher

a R2 a R2

With the Hydraulic Head Loss RatioWith the Hydraulic Head Loss Ratio



• At P1, a = 0.312 R2= 0.950,



• At P7, a = 0.917 R2= 0.997


becomes higher

• At P2, a = 0.508 R2= 0.974,



• At P8, a = 0.961 R2= 0.998


becomes higher

aR2 a R2



• At P1, a = 0.203 R2= 0.873

Closer to sea-side, Blocking the

water looks worse, but the

behavior is stable

• At P7, a = 0.855 R2= 0.991


becomes higher

• At P2, a = 0.267 R2= 0.867



behavior is stable

• At P8, a = 0.957 R2= 0.997


becomes higher

aR2 a R2



• At P1, a = 0.295 R2= 0.937



behavior is stable

• At P7, a = 0.979 R2= 0.997


becomes higher

• At P2, a = 0.671 R2=0.993

Even though it closes to sea-side

“a” value is relatively higher than

the Final closing section’s

• At P8, a = 0.984 R2= 0.999


becomes higher

a R2a

R2

SummarySummary

LocationP1 P3 P5 P7

a R2 a R2 a R2 a R2

No.60+25 0.2279 0.931 0.6899 0.978 0.9211 0.998 0.9722 0.997

No.65+00 0.3121 0.950 0.5111 0.924 0.6348 0.988 0.9169 0.997

No.69+80 0.2033 0.873 0.4448 0.924 0.7081 0.989 0.8549 0.991

No.82+00 0.2945 0.937 0.7458 0.993 0.9314 0.999 0.9788 0.997

- Sea-side (P-1,3) : Blocking the water looks Bad, but the behavior is stable - Lake-side(P-5,7)

: Blocking the water looks Good, and the behavior is stable

- Blocking the water of the general section is Good, but the final closing sections also

show a stable behavior

- Reinforcement does not require now at the final closing section, however, need to

monitor constantly


: Blocking the water looks Good, and the behavior is stable

- Blocking the water of the general section is Good, but the final closing sections also

show a stable behavior

- Reinforcement does not require now at the final closing section, however, need to

monitor constantly

Criteria(Ⅰ)Criteria(Ⅰ)

Statistical MethodsStatistical Methods

• Three times the standard deviation

were set to the criteria

• By setting the criteria,

we could measure

- Abnormal data

- Upward mobility of trend lines

- Downward mobility of trend lines

- Changes of trend line inclination

• After long-term monitoring, we will

- Review the adequacy of 3σ

as criteria

- Set the check-list in case of

odd behavior

Regression and 3-sigma Graph

Tide(m)

Criteria (-3σ)

Criteria (+3σ)

P1-P2(m)

Criteria suitable for long-term MonitoringCriteria suitable for long-term Monitoring

Examples of setting Criteria(Ⅰ) No.60+25Examples of setting Criteria(Ⅰ) No.60+25

P1P1 P3P3

P5P5 P7P7

Criteria(Ⅱ)Criteria(Ⅱ)

Criteria based on the change of Hydraulic Head Loss RatioCriteria based on the change of Hydraulic Head Loss Ratio

Criteria(Ⅱ)Criteria(Ⅱ)

• By plotting the daily values,

can predict changes of hydraulic

head loss ratio

Suitable for

long-term monitoring

Criteria based on the change of Hydraulic Head Loss RatioCriteria based on the change of Hydraulic Head Loss Ratio

Hydraulic H

ead Loss Ratio

Section SelectSection Select

• 3 on the Final Closing Section (No. 60+25, No. 65+00, No. 69+80)

• 1 on the General Section (No. 82+00)

• 3 on the Final Closing Section (No. 60+25, No. 65+00, No. 69+80)

• 1 on the General Section (No. 82+00)

In-situ ExperimentsIn-situ Experiments

• BIPS

: The gap was deemed to have been filled with the dredged sands

• In-situ permeability test : comparison of the permeability coefficient - Bottom protection layer / Embankment - General / Final Closing Section Difference is not large

• BIPS

: The gap was deemed to have been filled with the dredged sands

• In-situ permeability test : comparison of the permeability coefficient - Bottom protection layer / Embankment - General / Final Closing Section Difference is not large

ConclusionsConclusions

Building the Monitoring SystemBuilding the Monitoring System


• Evaluated the infiltration charcteristic by Hydraulic Head Loss Ratio


: Blocking the water looks Good, and the behavior is stable until now, evaluated need not reinforcement, but we will follow up the trend

• Suggested 2 Methods for Long-term Monitoring

- Criteria Based on Statistical Method

(Review the adequacy of 3σ by long-term monitoring) - Criteria based on the change of Hydraulic Head Loss Ratio (By the regression equation of trend line)


• Evaluated the infiltration charcteristic by Hydraulic Head Loss Ratio


: Blocking the water looks Good, and the behavior is stable until now, evaluated need not reinforcement, but we will follow up the trend

• Suggested 2 Methods for Long-term Monitoring

- Criteria Based on Statistical Method

(Review the adequacy of 3σ by long-term monitoring) - Criteria based on the change of Hydraulic Head Loss Ratio (By the regression equation of trend line)

ApplicationsApplications

• Verify the stability of the sea-dike of the final closing section

• Monitoring technology for seawater intrusion were secured

• Methods for the structures affected by the tide were presented

• Verify the stability of the sea-dike of the final closing section

• Monitoring technology for seawater intrusion were secured

• Methods for the structures affected by the tide were presented

Thank you very much!!

Documents

26 June 2012