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METHODS OF SLOPE REMEDIAL(SOIL NAIL / SHOTCRETE / VEGETATION)

KEMENTERIAN KESEJAHTERAAN BANDAR,PERUMAHAN, DAN KERAJAAN TEMPATAN

PRESENTATION OUTLINE

1. INTRODUCTION2. HISTORY OF SLOPE FAILURES

3. PROBLEM STATEMENTS4. METHODS OF SLOPE REMEDIAL

i. SOIL NAILii. SHOTCRETEiii. VEGETATION

5. CASE STUDY OF SLOPE REMEDIAL :BUKIT NANAS

6. FACTOR OF SAFETY (FOS) GUIDELINEFOR SLOPE STABILITY

7. CONCLUSION

1.0 INTRODUCTION

1. The POPULATION OF MALAYSIA was estimatedto be 30 572 466 people. This is an INCREASE of1.51% compared to the previous year.

2. The escalating numbers of population leads to theHIGH DEMAND FOR RESIDENTIAL AREA.

3. LIMITED AVAILABILITY OF FLAT LAND causes thedevelopment to shift towards the hilly areas.

4. Rapid development on hilly areas affects SLOPESTABILITYand poses RISKS and DETERIORATIONto properties and human lives.

5. Thus, SUITABLE SLOPE REMEDIAL WORKS isNECESSARY to strengthen the slope and ensurethe slope is safe.

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HUMAN ERRORSINVOLVING SLOPE FAILURECauses oflandslides

No. of Causes Percentage (%)

Design Errors 29 60

Construction Errors 4 8

Design &Construction Errors

10 20

Geological Features 3 6

Maintenance 3 6

Total 49 100

Reference: Proceedings of the 3rd International conference onGeotechnical Engineering for Disaster Mitigation and Rehabilitation 2011

1.0 INTRODUCTION

Over 700 landslideswere reported on 2015

410 landslidesoccurred on

federal roads

290 happenedalong state

roads

According to the landslide forensic statistic data from year 2004 to2007 of Slope Engineering Branch under the Public Works ofDepartment Malaysia, 57% of landslides were due to human factors,whereas only 29% and 14% due to physical and geological factors,and most of the landslides occured at man-made slopes

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SLOPE FAILURE AT BUKIT ANTARABANGSA(2008)

• Occurred on 6TH December

2008

• Location : Bukit Antarabangsa,

Ulu Klang, Selangor

• 14 Bungalows at Taman Bukit

Mewah and Taman Bukit

Utama destroyed

• 1.5 km from Highland Tower.

• Fatalities : 4 persons

• Injuries :15 persons

SLOPE FAILURE ATBUKIT ANTARABANGSA

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SLOPE FAILURE AT SETIAWANGSA• Emergency Response on Setiawangsa Slope Failure (28th December 2012)• 1 house were badly damaged and houses evacuation were applied

BRIEFING TO PUBLIC & MEDIA ON SLOPE FAILUREAT SETIAWANGSA

Briefing To Public

Briefing At Site

Briefing To Media And Kuala LumpurMayor

Briefing To Media At SiteBriefing To Public

DTM SETIAWANGSA SLOPE FAILURE

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DTM SETIAWANGSA SLOPE FAILURE

AFTER SLOPE FAILURE

PROPOSED REMEDIALWORK

SLOPE FAILURE AT BUKIT NANAS

Wangsa Maju,2006

Taman Tasik Perdana,2011Bangsar, 2011

La View En Rose Restaurant,2014

Bukit Segar,2010

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Jalan Ampang, 2013

Jalan Semantan, 2008

Cheras, 2011

Wangsa Maju,2006

SLOPE FAILURE AT LEBUHRAYA MAHAMERU

TRAFFIC CONGESTION

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SLOPE FAILURE AT RUMAH ANAK-ANAK YATIM DAN KEBAJIKANMADRASAH AL-TAQWA, HULU LANGAT

• Occurred on 21st May 2011• Location : Rumah Anak-anak Yatim dan

Kebajikan Madrasah Al-Taqwa, FelcraSemungkis, Batu 14, Hulu Langat.

• The number of Victims : 25 persons• Fatalities : 16 persons• Injuries :9 persons

SLOPE FAILURE ATHULU LANGAT

LANDSLIDE AT KM52.4, KARAK HIGHWAY

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DEBRIS FLOWIN RAUB,PAHANG

SLOPEFAILURE INSG. BESI,KUALA

LUMPUR

As a reminder, repair works are very,

and the reactive measures taken would givesimpact towards

thus…………

Preventive is better than corrective,

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LIST OF REMEDIAL WORK FOR SLOPE FAILURES(2008-2014)

Location CameronHighland KM 55

Jalan KualaTerengganu -

Jabor

Tasik KenyirSeksyen 37

ChangkatPersekutuan Bukit Nenas

Date of Failure 2008 2009 2010 2013 2013

End ofConstruction 2009 2010 2013 2014 2015

Area of Failuresq.m(sq.ft) 65,110sq.ft 44,200sq.ft 94,2200sq.ft 12,880sq.ft 93,260sq.ft

Cost(RM) 5,400,000.00 1,300,000.00 5,300,000.00 4,300,000.00 15,300,000.00

Cost/Sq.ft RM82 RM30 RM6 RM333 RM164

Type Bungalow 1-Storey Terrace

Build Up Size 4000 sq.ft 1500 sq.ft

LandCost/Sq.ft(A)

RM 40 RM40

Land Cost /unit(B) RM 160,000.00 RM 60,000.00

ConstrcutionCost/sq.ft(C)

RM 150 RM 150

ConstrcutionCost/Unit(D)

RM 600,000.00 RM 225,000.00

Cost perUnit(B+D)

RM 760 000.00 RM 285 000

Cost persq.ft(A+C)

RM 190/sq.ft RM 190/sq.ft

COMPARISON COST OF A BUNGALOW AND 1 STOREY-TERRACE HOUSE

=

=@

( 12,880 sq.ft)

( 4000 sq.ft)

( 1500 sq.ft)

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COMPARISON COST of HOUSING DEVELOPMENT &SLOPE REMEDIAL

NO LOCATIONCOST OF

CONSTRUCTIONBUNGALOW4000 SQ.FT

@

TERRACE1500 SQ.FT

1 BukitNenas(93,260sq.ft)

RM15 300 000.00 20 53

2 Tasik Kenyir Seksyen36 (94,2200sq.ft)

RM 5 300 000.00 6 18

3 Cameron HiglandKM55 (65,110sq.ft)

RM 5 400 000.00 7 18

4ChangkatPersekutuan(12,880sq.ft)

RM 4 300 000.00 5 14

5Jalan KualaTerengganu –Jabor(44,200sq.ft)

RM 1 300 000.00 2 5

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TYPE OF SLOPE REMEDIAL

TYPE OF SLOPEREMEDIAL

RETAINING WALL SOILREINFORCEMENT

SURFACE EROSIONCONTROL

1. GRAVITY WALL2. CANTILEVER WALL3. PILING WALL4. MSE WALL

1. SOIL NAIL2. GROUND ANCHOR3. GEOTEXTILE

1. HYDROSEEDING2. TURFING3. PLANTATION4. SHORTCRETE

O ve rtu rn in g

R e s is t in g

M o m en t

H o r izo n ta lF o rce

M o m en t R e s is t in g Fo rce

S u rch a rg e S o il W a te r

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Soil nailing can prevent landslides by insertingsteel reinforcement bars into the soil and

anchoring them to the soil

Soil nailing is a technique used to bring soilstability in areas where landslides might

be a problem.

WHAT IS SOIL NAILING?

TERMINOLOGY OF SOIL NAIL

Soil Nail Head(400x400 mm)

Reinforcement BarDiameter = 25, 32 & 40 mm

Steel Bearing Plate(200x200 mm)

Subject to calculation

20°

Nail Inclination :150 -200

Critical Slip Circle

Sources : Soil Nail Design Malaysia Perspective(Chow Chee Meng & Tan Yean Chin)

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TERMINOLOGY OF SOIL NAIL

Vertical Spacing of nail:Typically 1.5m to 2.5m

Horizontal Spacing of nail:Typically 1.5m to 2.5m

Minimum plate width of 200mmMinimum plate thickness 19mm

Concrete cover typically 50-75mmthick

Sources : Soil Nail Design Malaysia Perspective(Chow Chee Meng & Tan Yean Chin)

TYPICAL DETAIL OF SOIL NAIL

SOIL NAILING ANIMATION

SITE IS CLEARED SLOPE IS CUT SOIL NAILING IS INSTALLED

Insert Bar andGrouting

Hole is drilled

Steel PlatesShortcrete

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STRUCTURAL CAPACITY OF SOIL NAIL

Ultimate structural capacity, P = 0.87 x fy x As

Where: fy = characteristic strength of steel barAs = reinforcement area

= πd²/4

Steel BarDiameter

(mm)

Cross-sectionalArea of Pile, Ac

(mm²)

25 490

32 804

40 1,256

* Normal Size Use in Malaysia

Ultimate structural capacity, P

P = 0.87 x fy x As= (0.87 x 460 N/mm² x 490 mm²) / 1000= 196 kN

*Structure Capacity (refer BS 8110: Clause 7.4.4.3.1)

Structural Capacity Soil Nail vs Steel Bar Size

*use FOS = 1.5 according to BS 8081: 1989

196

322

503

786

131

215

335

524

0

100

200

300

400

500

600

700

800

900

25 32 40 50

Stru

ctur

e Ca

paci

ty (

N/m

m2)

Diameter Steel (mm)

Structural Capacity Soil Nail vs Steel Bar Size

Ultimate Structure Capacity Allowable Structure Capacity

SENSITIVITY ANALYSIS

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Sand

Cement

Steel Casing, Nut & MS plate

T32 Galvanised Hot Rolled Steel

Excavator Cement Mixture

Drilling Machine Case 580 Super K

Hydraulic Screw Compressor

Air Compressor Grouting Pump

Guniting Spray

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SOIL NAILING WORK SEQUENCESSTEP 1Clearing , scaling and trimming

Clear and remove from site all obstacleover the areas for the construction

Trimming slope to perform proposedslope inclination

SOIL NAILING WORK SEQUENCESSTEP 2Survey & Paging soil nail point

Survey soil nail point to measure actualquantity of soil nail

SOIL NAILING WORKS SEQUENCESSTEP 3Preparation of Soil Nail Works

Installation of staging to perform soilnailing works

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SOIL NAILING WORK SEQUENCESSTEP 4Drilling soil for installation of soil nail

AirCompressor

Drilling soil nail point using drillingmachine

SOIL NAILING WORK SEQUENCESSTEP 5Installation of soil nail

Inserting reinforcement bar (size as perdesign) in the hole

Reinforcement bar

SOIL NAILING WORK SEQUENCESSTEP 6Grouting Process

Full grouting apply after installing thereinforcement bar in the hole ( cement

grout as per design )

Reinforcement bar

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SOIL NAILING WORKS SEQUENCESSTEP 7Locking Soil Nail

Install soil nail plate andlocking using bolt & nut

SOIL NAILING WORK SEQUENCESSTEP 8Testing – Pull Out Test

Perform pullout test to determine theperformance of soil nailing based on

design working load

Pull Out Test(According to BS 8081:1989)

• The pullout test on soil nail generally1.5 times the working load asspecified in BS 8081:1989.

• Load at this stage is called thepullout capacity.

• Tests are carried out to determine thestrength of soil nailed structures

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PROGRESS PICTURE

SETTING UP FOR PULL OUT TESTSETTING UP FOR PULL OUT TEST

GAUGE METER READING WHILE PULL OUT TESTGAUGE METER READING WHILE PULL OUT TEST PULL OUT TEST IN PROGRESSPULL OUT TEST IN PROGRESS

PULLOUT ON SITE

Production Rate

SPT VALUE LENGTH (m)TIMES REQUIRED

/ 1m LENGTH(minute)

TIMES REQUIRED/ 6m LENGTH

(minute)

TIMES REQUIRED/ 12m LENGTH

(minute)

10 1 2 12 24

20 1 6 36 70

30 1 7.5 45 90

40 - 50 1 10 60 120

SPT VALUEAVERAGE DAILY RATE FOR 6M

REINFORCEMENT

AVERAGE DAILY RATE FOR 12MREINFORCEMENT

10 40 20

20 14 7

30 11 6

40 - 50 8 4

EXAMPLES OF SOIL NAILING USINGMACHINERY

Excavator mounted drill rig

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VIDEO SOIL NAIL

DEFINITION OF SHOTCRETE

Shotcrete is a today an all-inclusive term thatdescribes spraying concrete or mortar with either adry or wet mix process through a hose and nozzle

onto a surface

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CLASSIFICATION OF SHOTCRETEDRY MIX1. Dry materials including cement,

aggregate, and ad-mixture are mixedtogether through a hose and then, atthe nozzle via a water ring, water isinjected evenly throughout the mix.

2. Dry mix usually uses for Slope protectionsurface (Shotcrete)

WET MIX1. Materials including cement, aggregate,

ad-mixture and water – are mixedtogether before being pumped through ahose.

2. Wet mix usually uses for Groutingprocess for Soil Nail Work

Application of Dry MIX

Application of Wet MIX

Gunite is trademarked name that isincorrectly used to describe the dry mix

shotcrete process

DEFINITION OF GUNITE

EXAMPLE APPLICATION OF SHOTCRETE

Shotcrete is used for slopesurface protection

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EXAMPLE APPLICATION OF SHOTCRETEShotcrete is used for concrete grouting of

soil nail (Wet Mix)

Grout

INGREDIENT OF SHOTCRETE

Sand Cement and Admixture

Cement Mixture Guniting Spray Grouting Pump

Material

Machinery

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SEQUENCE OF SHOTCRETE WORK ATTAMAN BUKIT SEGAR, CHERAS

SITE CLEARINGSITE CLEARING INSTALLATION OF BRCINSTALLATION OF BRC

SPRAY CONCRETESPRAY CONCRETESPRAY CONCRETESPRAY CONCRETEFINISH SHOTCRETEFINISH SHOTCRETE

VIDEO SHOTCRETE

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VEGETATION FOR SLOPE REMEDIAL1. Vegetation influences slope stability by:

• Providing cover for the impact of rain falling onslopes and prevent erosion on slope surface

• Providing root systems by transferring shear stressin soil to the tensile resistance in the root

2. Types of vegetation:• Hydroseeding• Turfing

HYDROSEEDING

HYDROSEEDING• Application of grass seed mixed with fertiliser and

nutrient by spraying method over the ground• The grass seed will grow eventually and the root

of the grass will act as an organic reinforced fiberand hold the surface soil.

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HYDROSEEDING WORKS

GRASS SEED, FERTILIZER ANDNUTRIENTS ARRIVED AT SITEGRASS SEED, FERTILIZER ANDNUTRIENTS ARRIVED AT SITE

EXAMPLE OF GRASS SEEDEXAMPLE OF GRASS SEED SPRAY GRASS SEEDSPRAY GRASS SEED

SPRAY GRASS SEEDSPRAY GRASS SEEDGRASS BEGIN TO GROWGRASS BEGIN TO GROWFINISH HYDROSEEDING WORKSFINISH HYDROSEEDING WORKS

VIDEO OF HYDROSEEDING

BEFORE AND AFTER HYDROSEEDING

BEFOREBEFORE

AFTERAFTER

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TURFING

TURFING

• Turfing is a direct application of grass withdeveloped roots on a slope surface

• The relatively matured grass will grow easierand extend its root into the soil to strengthenthe overall surface.

TURFING WORKS

BEFORE REMEDIAL

AFTER REMEDIAL

LIMBANG, SARAWAK

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TURFING WORKS1 2

3 4

1. SOIL NAIL2. HYDROSEEDING

Geotechnical Forensic Unit,3rd Floor, Block 5, Unipark Suria , Jalan Ikram-Uniten, 43000 Kajang, Selangor, Malaysia.Tel : (603) 87383388 Fax: (603) 89221134 www.ikram.com.my

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SATELLITE IMAGE OF FAILURE AREA

SMK StJohn

Convent BktNanas

SYABAS TreatmentTank

FailureLocation 1A

FailureLocation 2B

Jalan Ampang

Jalan SultanIsmail

Jalan P Ramlee

Jalan Raja Chulan

Jalan Bukit Nanas

FailureLocation 1B

FailureLocation 2A

LAYOUT PLAN OF LOCATION FAILURE 1

Location 1 A Location 1 A Location 1A

Location 1B

LAYOUT PLAN OF LOCATION FAILURE 2

Stone Pitching Moved Forward

Rubble Wall

20m

6m

6m

Location 2A

Location 2B

Panoramic View Of Location 2B

Staircase To Basement Parking

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REMEDIAL LAYOUT PLAN (LOCATION 1)

LOCATION 1B

LOCATION 1A

Anchored RCWall

Soil Nailing

REM

EDIA

L C

ROSS

SEC

TIO

N(L

OC

ATI

ON

1)

LOCATION 1B

LOCATION 1A

4m

12m18m

Anchored Retaining Wall

Soil Nailing

Remedial Item Location 1A Location 1B

RC Wall

Height (4m) 130m Length 35m Length

Tieback SoilNail(18m)

330 nos 80 nos

SlopeStrengtening

Soil Nail(12m length)

2700 nos 324 nos

SurfaceProtection

Enkamat 6000 m² 700 m²

FoundationMicropile

(6m length)55 nr 13 nr

SLOPE STABILITY ANALYSIS(LOCATION 1A)

1A

1A

Slope RemedialLength of Soil Nailing – 12m

Exposed Height Anchored RC Wall – 4m

Failure Area

Before

After

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SITE PHOTO BEFORE & AFTERREMEDIAL (LOCATION 1A)

SIDE VIEW

FRONT VIEW

JAN 2014JAN 2014 SEPTEMBER 2014SEPTEMBER 2014 NOVEMBER 2014NOVEMBER 2014

JAN 2014JAN 2014 SEPTEMBER 2014SEPTEMBER 2014 NOVEMBER 2014NOVEMBER 2014

DTM OFFAILURE AREA

(LOCATION1A)

Before

After

32mRL

95mRL

32mRL

95mRL

DTM VIDEO OF BUKIT NENAS

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GUIDELINE FOR SLOPE STABILITY(FACTOR OF SAFETY)

GUIDELINE

F.O.SNATURAL SLOPE

(GLOBAL/LOCAL)

F.O.SMAN MADE SLOPE

(GLOBAL/LOCAL

F.O.STEMPORARY SLOPE

(GLOBAL/LOCAL)

DBKL GUIDELINE

1.3 1.5 1.2PANDUAN REKABENTUK

CERUN (JKR)

GARIS PANDUAN PERANCANGANPEMBANGUNAN DI KAWASAN BUKIT DANCERUN BAGI WILAYAH PERSEKUTUAN KUALALUMPUR, 2010

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JKR GUIDELINE FOR SLOPE DESIGN

7.0 CONCLUSION

• Soil nail, vegetation and shotcrete are types ofremedial works for SLOPE STABILIZATION andPROTECTION of slope surface.

• Understanding the methods of remedial works iscrucial to ensure the works are ACCORDING tothe STANDARD SPECIFICATION andSEQUENCES.

• KuLSIS is an example of comprehensive slopeinformation system which acts as a tool for localauthorities to MANAGE SLOPE EFFICIENTLY.