Lecture 3- Engineering of · PDF fileENGINEERING OF SLOPE Planning, Design, Construction & ......

G&P Geotechnics Sdn Bhd (G&P Geotechnics Sdn Bhd (www.gnpgroup.com.mywww.gnpgroup.com.my))G&P Geotechnics Sdn Bhd (G&P Geotechnics Sdn Bhd (www.gnpgroup.com.mywww.gnpgroup.com.my))
By Ir. Dr. Gue See Sew & Ir. Dr. Wong Shiao Yunhttp://www.gnpgeo.com.my
ENGINEERING OF SLOPEENGINEERING OF SLOPEPlanning, Design, Construction & Planning, Design, Construction &
Maintenance ConsiderationsMaintenance Considerations
Cover courtesy of JURUTERA Sept 2008 ed.

G&P Geotechnics Sdn Bhd (G&P Geotechnics Sdn Bhd (www.gnpgroup.com.mywww.gnpgroup.com.my))
CONTENTS
IntroductionIntroduction Policies & Legislation Planning of HillPlanning of Hill--Site DevelopmentSite Development Analyses & Design of SlopesAnalyses & Design of Slopes Design of Slope Strengthening WorksDesign of Slope Strengthening Works Construction Control & Site SupervisionConstruction Control & Site Supervision Maintenance of SlopesMaintenance of Slopes ConclusionConclusion

INTRODUCTIONINTRODUCTION

Soil Nailed Slope Failure

Policies and LegislationPolicies and Legislation

IKRAM
IEM
Urban & Rural
Planning
Department
(JPBD)
Ministry of
Housing & Local
Government
(MHLG)
MPAJ(Local Authority)
JMG
DOE
Governmental
& Private
Agencies
Source of Hillsite Development Guidelines

Simplified Slope Classification
Insitu terrain 25 - 35Class III
Insitu terrain < 15Class I
Insitu terrain 15 - 25Class II
Insitu terrain > 35Class IV
Gradient of Natural TerrainClassifications

Policies and Legislation
These guidelines & regulations: are conflicting & unclear are too complicated for implementation are subjected to various interpretations
IEM has formulated policies and procedures for landslide risk mitigation on hillsite developments

THE INSTITUTION OF ENGINEERS, MALAYSIA
POSITION PAPER FOR MITIGATING THE RISK
OF LANDSLIDE ON HILL-SITE
DEVELOPEMENT
IEM

Legend:HT = Total height of slopeHL = Localised height G = Global angle of slopeL = Localised angle of slope
G
L1HL1
HL2
L2
Ground Profile
IEM

Current Status
JKR Guidelines for Slope Design, 2010
DBKL Guidelines for Planning of Hilly & Sloping Areas, 2010
Negeri Selangor Guidelines for HillsiteDevelopment

PLANNING STAGEPLANNING STAGE
Photo courtesy of http://freephotooftheday.clientk.com

Planning StagePlanning Stage Desk Study (e.g. geological map, aerial photos) Site Reconnaissance
Geological Input
Terrain Mapping
Geological Mapping
Erosion &
Instability Evaluation
Surface Hydrogeological
Assessment, Natural Water Course
Terrain
Classification(JMG)
Rock Type JointsWeathering
grades
Geohazard & Geological
Constraints

SI Planning

Planning of Development LayoutPlanning of Development Layout Geotechnical input in early stage Maximise environmental preservation by
clustering development

Planning of Development LayoutPlanning of Development Layout Allow higher density development within
minimum plinth area Leave green on hill slope
Photo courtesy of www.lushhomemedia.com

Photo courtesy of http://freephotooftheday.clientk.com
ANALYSIS & DESIGN ANALYSIS & DESIGN
OF SLOPESOF SLOPES
Photo courtesy of http://temp2.fotop.net

Analysis & Design of SlopesAnalysis & Design of Slopes
ACT 133 & UBBL
Natural slopes adjacent to development shall be assessed on its existing slope safety.
In-line with judgement by Justice James Foong in the Highland Tower case.

IMPORTANTIMPORTANT Slope Stability FactorsSlope Stability Factors
Soil Properties
Slope Geometry Groundwater table Slope Maintenance

Soil Properties
Steep Rockface Gentle Beach

Slope Geometry
Steep Slopes Has Higher Risk of Failing
Steep Slope Gentle Slope

Groundwater table
High Groundwater Increases Risk of Failure
Low Groundwater Table
High Groundwater Table

Rainwater = Runoff + Infiltration
Erosion Rise in Water Level
Design for 10-yr ARI or representative groundwater level.
Slopes of High Risk-to-Life check sensitivity of water level.
Groundwater TableGroundwater Table

SLOPE STABILITY ANALYSISSLOPE STABILITY ANALYSIS

Methods of Stability AnalysisMethods of Stability AnalysisAnalyse as SOIL = Grade IV to VI
Methods :- (Should check both)
(A) Circular Slip Failure (e.g. Simplified Bishop)
- for deep layer without structural features.
(B) Non-Circular or Wedge Slip Failure
(e.g. Janbu , Morgenstern & Price)
- failures often at relict joints or boundaries between weathering zone.

External LoadingExternal Loading
Loadings from :- Traffic Building Foundations Retaining Wall Spoil heaps

FACTOR OF SAFETYFACTOR OF SAFETY
Considers TWO Main Factors : Risk-to-Life Economic Risk
Three Level of Risks :- Negligible , Low , High

HighStorage of Dangerous Goods
HighOccupied Buildings (residential, etc)
LowPublic waiting areas (bus stops, petrol stations, railway platforms)
LowRoads with high traffic
LowDensely used playgrounds, car parks.
NegligibleStorage Compound
NegligibleRoads of low traffic
NegligibleOpen-air recreation, Country Parks
RiskRisk--toto--LifeLife

Economic RiskEconomic Risk
HighExcessive structural damages
HighEssential services (extended period)
LowRoads of Statagic importance
LowEssential services (temporary loss = power, water, gas mains etc.)
LowRural Roads + Primary Distributor Roads
NegligibleOpen air car parks
NegligibleRoads of low traffic & not sole access
NegligibleOpen-air recreation, Country Parks

Cut & Fill Soil SlopesCut & Fill Soil Slopes Mainly follows Geotechnical Manual for Slopes of
Hong Kong Vertical he

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