OnOn--Line Risk Management Line Risk Management

for Slopes using FOS & TRSfor Slopes using FOS & TRS

presentation by

K T Chang

Prof., Kumoh National Institute of Technology. South Korea

Albert Ho Associate Director, Ove Arup & Partners Hong Kong Ltd,

Michelangelo(1475Michelangelo(1475Michelangelo(1475Michelangelo(1475----1564)1564)1564)1564)

Introduction and backgroundIntroduction and backgroundIntroduction and backgroundIntroduction and background

The RealThe RealThe RealThe Real----time Monitoring Systemtime Monitoring Systemtime Monitoring Systemtime Monitoring System

Typical Typical Typical Typical ApplicationApplicationApplicationApplication

An OverviewAn OverviewAn Overview

Closing RemarksClosing RemarksClosing RemarksClosing Remarks

Speed : Cost

Safety

Quality : Current inspection techniques are subjective and difficult to verify with audits, indicating that quality is variable depending on the individual, circumstances.

Auditability : In an increasingly litigious society, there is a greater need to prove that the inspection was undertaken and to have raw data available for review by an independent party,

Monitoring

▶Background

● Investment: 600 Billion for last 30yrs.

● Importance of Maintenance rather than Construction.

● Design & Construction : 85%, Maintenance:15%

● Disaster Prevention: Tremendous Savings

▶ Personal Motivation

● Uncertainties especially in the Field ofGeotechnical Eng.

● Confidence of Design, Lack of information through the follow-ups.

No Assessment, No ImprovementNo Assessment, No ImprovementNo Assessment, No ImprovementNo Assessment, No ImprovementNo Assessment, No ImprovementNo Assessment, No ImprovementNo Assessment, No ImprovementNo Assessment, No Improvement

Key IdeasKey Ideas

Daily basesDaily basesDaily basesDaily basesDaily basesDaily basesDaily basesDaily bases-------- Risk management Risk management Risk management Risk management Risk management Risk management Risk management Risk management

MultiMultiMultiMultiMultiMultiMultiMulti--------disciplinarydisciplinarydisciplinarydisciplinarydisciplinarydisciplinarydisciplinarydisciplinary

From Signal process to information based, From Signal process to information based, KnowledgeKnowledge--based monitoring Systembased monitoring System

SLOPES on CHIP ?SLOPES on CHIP ?

PASTPASTPASTPAST

PRESENTPRESENTPRESENTPRESENT

PROSPECTIVEPROSPECTIVEPROSPECTIVEPROSPECTIVE

Types of Sensors usedTypes of Sensors usedTypes of Sensors usedTypes of Sensors usedTypes of Sensors usedTypes of Sensors usedTypes of Sensors usedTypes of Sensors used

Fiber Optic SensorFiber Optic SensorFiber Optic SensorFiber Optic Sensor

TRS SensorTRS SensorTRS SensorTRS SensorTRS SensorTRS SensorTRS SensorTRS Sensor

Rain GaugeRain GaugeRain GaugeRain GaugeRain GaugeRain GaugeRain GaugeRain Gauge

TiltmeterTiltmeterTiltmeterTiltmeterTiltmeterTiltmeterTiltmeterTiltmeter

-------- Best use of IT links,Best use of IT links,Best use of IT links,Best use of IT links,Best use of IT links,Best use of IT links,Best use of IT links,Best use of IT links,

-------- DurabilityDurabilityDurabilityDurabilityDurabilityDurabilityDurabilityDurability

-- SimplicitySimplicitySimplicitySimplicitySimplicitySimplicitySimplicitySimplicity

-- CostCostCostCostCostCostCostCost--------effectivenesseffectivenesseffectivenesseffectivenesseffectivenesseffectivenesseffectivenesseffectiveness

GPSGPSGPSGPSGPSGPSGPSGPS--------TRSTRSTRSTRSTRSTRSTRSTRS

Topographical and climatic features creating landslidesTopographical and climatic features creating landslidesTopographical and climatic features creating landslidesTopographical and climatic features creating landslidesTopographical and climatic features creating landslidesTopographical and climatic features creating landslidesTopographical and climatic features creating landslidesTopographical and climatic features creating landslides

High proportion of land mass consists of mountains and hills. High proportion of land mass consists of mountains and hills. High proportion of land mass consists of mountains and hills. High proportion of land mass consists of mountains and hills.

---- cut slopes are inevitable when constructing roadscut slopes are inevitable when constructing roadscut slopes are inevitable when constructing roadscut slopes are inevitable when constructing roads

High annual rainfall levelsHigh annual rainfall levelsHigh annual rainfall levelsHigh annual rainfall levels

Alternate process of freezing and thawing due to extreme Alternate process of freezing and thawing due to extreme Alternate process of freezing and thawing due to extreme Alternate process of freezing and thawing due to extreme

climatic variationsclimatic variationsclimatic variationsclimatic variations

Introduction and background:Introduction and background:Introduction and background:Introduction and background:

Cut Slopes Cut Slopes Cut Slopes Cut Slopes Cut Slopes Cut Slopes Cut Slopes Cut Slopes -------- the South Korean examplethe South Korean examplethe South Korean examplethe South Korean examplethe South Korean examplethe South Korean examplethe South Korean examplethe South Korean example

Total length of national roads : 14,000km (8,750miles)Total number of cut slopes exceeding 6m in height: 12,600

Constitution of cut-slopes

Rock 79%, soil 6%, mixed materials 15%

Cut slopes constructed during the 1970s∼1980s were made with a steep slope angle which reduced construction costs,safety not being the primary factor

Progress of CutProgress of CutProgress of CutProgress of CutProgress of CutProgress of CutProgress of CutProgress of Cut--------slopes Maintenanceslopes Maintenanceslopes Maintenanceslopes Maintenanceslopes Maintenanceslopes Maintenanceslopes Maintenanceslopes Maintenance

Run to FailureRun to FailureRun to FailureRun to Failure until 1994,

Preventive MaintenanceMaintenanceMaintenanceMaintenance since 1995

CSMS system ( D/B by experts ) since 1998,

Predictive MaintenancePredictive MaintenancePredictive MaintenancePredictive Maintenance ssssince 2002,

based on Real-time monitoring system ;

▶ 2002 : 4 trial sites, ▶2003 : 15 sites

▶ 2004 : 15sites, ▶ 2005 : 15 Sites

▶ 2006 : 15 Sites ▶ 2007 : 20 Sites

The TRS Sensor combines the The TRS Sensor combines the following:following:

•• The tension wire sensorThe tension wire sensor•• The The tiltmetertiltmeter sensorsensor

The system enables measurementThe system enables measurement ofofTTranslation,ranslation, RRotationotation andandSSettlement.``ettlement.``

The RealThe RealThe RealThe Real----time Monitoring Systemtime Monitoring Systemtime Monitoring Systemtime Monitoring System

TRS Sensors

TRS Sensors TRS Sensors TRS Sensors TRS Sensors TRS Sensors TRS Sensors TRS Sensors TRS Sensors

Arrays of TRS Sensors Arrays of TRS Sensors

Suppose that one of the

sensors is moving downwards

centering around a relatively

stable point on a defined

section.

Figure1. on the right hand

side shows the procedure of

vector analysis about how to

track down the failure plane

with the data acquired from

TRS sensors, which stands

for T; translation,

R; rotation, S; settlement.

Figure. 1

�� Vector AnalysisVector Analysis

- Location of slip surface using deformation vector

( ),A AA x y

( ),B BBx y

( ),C CCx y

R

O

I

OKk

KJk

JIk

'K

'J

''K ''JX

Y

()1TSy f x=

( ,O OOx y ) ( ),K KKx y

( ),J JJ x y

1

2

3

4

5

67

8

9

Legend:

1. Drilled hole

2. Cement

3. Pipe

4. Junction box

5. Communication cable

6. TRS sensor

7. Tension wire

8. Rain gauge

9. Data Logger

Tension Wire Sensor

Installation

One of the advantages with the One of the advantages with the One of the advantages with the One of the advantages with the tension wire sensor is that it tension wire sensor is that it tension wire sensor is that it tension wire sensor is that it measures relatively large measures relatively large measures relatively large measures relatively large displacements without the wire displacements without the wire displacements without the wire displacements without the wire being severedbeing severedbeing severedbeing severed

Rain GaugeRain Gauge

Examples of Application

Navigation SystemNavigation System

Real-Time Information for Traffic Safety

The Dangers of a Storm

Monitoring Data(March, 15 2000 ~ Sept., 2001)

2001년 6월중순경부터 응력의 변화가

급격히 증가하였는데 이 것은 2001년 월

별 강우량 집계에 나타나 있듯이 2001년

6월18, 19. 24일에 약200mm 이상의 강

우가 집중된 영향으로 보여진다. 1월부

터 6월까지는 강우량이 월 평균 수십mm

에 불과하였으며, 그 시기에 전국적인 심

한 가뭄을 겪고있었다 이러한 가뭄이 계

속되는 시기의 지반은 지반자체가 보지

하고있는 함수량이 말라버림으로서 겉보

기 점착력(Apparant cohesion)이 제거

되어 있는 상태라 할 수 있다. 이러한 지

반에 갑작스런 집중호우로 인해 포화상

태의 지반 단위중량증가로 인한 지반거

동으로 사료된다.

CATERGORISATION

RISK

&

CONSEQUENCES

OF FAILURE

Industrial development at foot of slope in South Korea

Industrial buildings in close proximity to foot of slope

Stabilising measures carried out a portion of slope

Incipient failure of the unsupported section of the slope

Failure of the unsupported section of the slope

Slope failure showing failed soil nails and shotcrete

System Schematic Real-time analysis program

DB ServerDB ServerDB ServerDB Server Web ServerWeb ServerWeb ServerWeb ServerClient PCClient PCClient PCClient PC

Internet (ADSL)Internet (ADSL)Internet (ADSL)Internet (ADSL)

CellularCellularCellularCellularWarningWarningWarningWarningSMS (Short Message SMS (Short Message SMS (Short Message SMS (Short Message Service)Service)Service)Service)

Central Maintenance Centre

Real-Time Monitoring for Slopes

DetectorDetectorDetectorDetectorSystemSystemSystemSystem

평면평면평면평면 + 원호파괴원호파괴원호파괴원호파괴

인장균열인장균열인장균열인장균열

정착지점정착지점정착지점정착지점

롤러장치롤러장치롤러장치롤러장치

Tension wire Tension wire Tension wire Tension wire 센서센서센서센서

자동자동자동자동 강우량강우량강우량강우량 센서센서센서센서자동자동자동자동 강우량강우량강우량강우량 센서센서센서센서

현장현장현장현장 설치설치설치설치 모식도모식도모식도모식도

Rain gauge

Site

Tension wire

Failure surface

Typical on-screen Real-Time Monitoring

display for Kimhae

KNBKNBKNBKNB

0000

200200200200

400400400400

600600600600

800800800800

1000100010001000

1200120012001200

1400140014001400

1600160016001600

1800180018001800

2000200020002000

2200220022002200

2400240024002400

2600260026002600

4/204/204/204/20 5/305/305/305/30 7/97/97/97/9 8/188/188/188/18 9/279/279/279/27 11/611/611/611/6 12/1612/1612/1612/16 1/251/251/251/25 3/63/63/63/6 4/154/154/154/15 5/255/255/255/25 7/47/47/47/4 8/138/138/138/13

경과시간(date)경과시간(date)경과시간(date)경과시간(date)

변형률(με)

변형률(με)

변형률(με)

변형률(με)

0000

20202020

40404040

60606060

80808080

100100100100

120120120120

140140140140

s4(2.5m)s4(2.5m)s4(2.5m)s4(2.5m)

s3(8.5m)s3(8.5m)s3(8.5m)s3(8.5m)

s2(11.5m)s2(11.5m)s2(11.5m)s2(11.5m)

s1(14.5m)s1(14.5m)s1(14.5m)s1(14.5m)

강우량(mm)강우량(mm)강우량(mm)강우량(mm)

Deformation/time plot with rainfall levels for Kimhae

Predictive Models

Typical on-screen display utilising

the innovative network camera

Sensor with warning lamp

Automatic control of traffic using signalling system

http://www.gmgnow.kr/google_map/

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Please contact the HKIE

Geotechnical Division should you

wish to have a complete version.