Final Report Ers

Cadangan Pembinaan dan Baikpulih Tembok Tembok Penahan Sungai Muar di Pekan Panchor, Muar, Johor

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SECTION 1 INTRODUCTION AND PROJECT DESCRIPTION

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1.1 Introduct Introduction ion

There has a riverbank failure induced by extreme low tie, when stability is most critical due to loss of support from the water and very soft marine Clay at Sungai Muar Pekan Panchor, Muar, ohor! abatan Pengairan dan Saliran Malaysia "PS# intends to carry out remedial remedial works works for the failures failures and has appointed appointed $S Consult Consultant ant Sdn! %hd! %hd! to propose suitable slope stabili&ation scheme!

Figure 1.1: Slope failure at Sungai Muar riverbank

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The propose slope stabili&ation scheme will be focusing into the design of appropriate earth earth retainin retaining g structur structures, es, upgradi upgrading ng the existing existing road base, and also propose the construction construction method of slope stabili&ation stabili&ation scheme! The type of earth retaining structures that will be propose will consider the suitability of the proposed proposed structures with respect to the ground and surrounding conditions, construction efficiency, efficiency, material availability, availability, and also total pro(ect cost!

This report will provide all re)uired information regarding propose remedial remedial work of slope failure at Sungai Muar, Pekan Panchor, Muar, ohor! This report will cover all re)uired information including*+

i#

Pro(ect background

ii# ii#

Site Site inve invest stig igat atio ion n  -eot -eote echni chnica call con consi side dera rati tion on

iii# iii#

$nal $naly ysis sis on on like likely ly caus cause e of slop slope e fail failur ure e

iv# iv#

Prop Propos osed ed .art .arth h /et /etai aini ning ng Stru Struct ctur ure e des desig ign n

v#

Prop Propos osed ed .art .arth h /eta /etain inin ing g Stru Struct ctur ure e anal analy ysis sis

vi# vi#

Comp Compar aris ison on with with oth other er .art .arth h /et /etai aini ning ng Str Struc uctu ture res s opt optio ions ns

vii#

Conclusion

0

Cadangan Pembinaan dan Baikpulih Tembok Penahan Sungai Muar di Pekan Panchor, Muar, Johor

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1.2 Project Description Project Title: Cadangan Pembinaan dan %aikpulih Tembok Penahan Sungai Muar di Pekan Panchor, Muar, ohor

Client: abatan Pengairan dan Saliran Malaysia "PS#

Geotechnical & Structural Consultant: $S Consultant Sdn %hd, Consulting .ngineers, o '12, %lok ', Menara 3S%C, alan Sultan 4smail, 56078, 9uala :umpur

Project objective:

$!

To reinstate  stabili&e the failed slope at the location of Sungai Muar at Pekan Panchor, Muar, ohor!

%!

To proposed the method of slope stabili&ation scheme ".arth /etaining Structure#!

C!

To proposed the construction methods for slope stabili&ation!

;!

To proposed the upgrading scheme for existing road base!

Project location: The location of slope failure is at Sungai Muar, Pekan Panchor, Muar, ohor! The riverbank of Muar river was collapsed due to several factors "refer to section '#!
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Panchor, Muar

Figure 1.2: Location of Pekan Pancor !"oogle #aps$ 2%%&'

S+0"*I M+*,

F*IL+,- /0-

Figure 1.(: Location of failure )one

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Scope of work:

i#

isual inspection of the site to observe significant geotechnical features>

ii#

Planning and reviewed t he ground profiles of the sub(ect site from the survey plan>

iii#

Planning and interpret the borehole logs obtained from the soil investigation work conducted at the sub(ect site!

iv#

,evie and interpret the results of the laboratory testing program to determine the classification, and strength characteristics of the soils and rocks encountered>

v#

;eveloped relevant cross3section across the slope of the ? failed @ area, and predict the subsurface profiles with appropriate geotechnical parameters to the various strata intersected>

vi#

vii#

Commented on appropriate slope protection #easures>

viii#

Summari&ed work in a written report!

4n undertaking this pro(ect, the key issues are* + "a#

Pekan Panchor, Muar, ohor is classified as medium risk to landslide! The riverbank slope has totally collapsed after low tie period . Progressive failures has caused total cut off of the road! /ectification works must be carried out immediately to prevent further failure that can damaged the houses and overall improvement on the safety of the slope!

"b# The investigation and stabili&ation works should not aggravate the precarious conditions prevailing at the sites! "c# Consideration will be given to the short and long term environ#ental i#pacts of the proposed options to rectify the slopes!

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SECTION 2 SITE INVESTIGATION

2.1

Introduction

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Several investigations were conducted on site to determine the caused of the slope failure!
The objectives of site investigation are*+ a#

To assess the general suitability of the site and neighborhood for the proposed

works, from a geological and geotechnical point of view! b#

To provide suitable geotechnical data for all aspects of an economic, safe and

reliable design of foundations, earthworks and temporary works, including assessment of the effects of any previous uses of the site! c#

To assess the problems and constraints associated with the construction of the

works arising from the soil or groundwater conditions and to plan the best method of construction! d#

To assess the )uantity, )uality and ease of extraction of construction materials

suitable for the works! e#

To determine the changes in the stability, drainage and other geotechnical

aspects of the site and the surrounding ground and buildings, this might be initiated by the construction works! f#

To make comparison on the construction works by alternative methods or at

alternative sites!

2.2 Scope of site investigation ork The site investigation work are consist of several stages that are site reconnaissance, planning S4 layout, planning S4 methods, sampling A testing, and reporting A assessment!

'!'!1

Site reconnaissance

Site reconnaissance exercise main ob(ective is to collect as much as possible the information from the location of the slope failure! This exercise is being executed after the event of failure to identify the most like caused of the failure physically! %eside that,

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site reconnaissance also important to investigate the general condition of the site such as the site topography, existing building around the site, basic geology, detailed of access, entry and height restrictions! $ll of this information is re)uired in order to propose the suitable design system for the slope reinstatement!

'!'!'

Site 4nvestigation layout

Total = numbers of boreholes was employed for the purpose of subsurface investigations! The location of boreholes is carefully locate in order to reveal the most efficient and valuable information especially for design purposes!
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Figure 2.1: 5oreole location %orehole number 1,', and 0 was located at the location of failure! %orehole number = is located at the left side of the failure while borehole number ' is located at the toe of the failure "see
'!'!0

Site 4nvestigation Method

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The choice of site investigation method is highly depend on the purpose of subsurface investigation!

/otary wash boring was employed in this

investigation "see
The termination criteria of boreholes have been set+up! %orehole was terminated after the either of the following criteria is fulfilled* a#

Continuous solid rock coring to a minimum depth of two "'# times 1!5 m using core barrels is re)uired!

b#

Seven "7# continuous times of SPT+ D 58

c#

Maximum fourty "=8# meter of borehole depth below ground level

d#

$ll the above criteria shall be confirmed and acknowledge by engineerEs representative at site before termination!

The above termination criterion is to ensure that firm and reliable rock )uality level is identified for slope repair system!

'!'!=

Sampling and testing

Soil samples are collected in the form of undisturbed or disturbed but representative when drilling in progress! ;isturbed samples were normally used for identification and laboratory classification tests! /epresentatives portions of each sample are sealed in polythene bags and label indicate sample numbers and depth taken, and sent to the laboratory!

Fndisturbed samples are collected by employing hydraulic thrust on thin wall sampling tubes of 68mm diameter for very soft cohesive soils! The samples will then promptly seal with paraffin wax to prevent any loss of moisture! $ll the undisturbed samples are place in cushion boxes and transport with great care to the laboratory to ensure minimum disturbance to the soil!

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The laboratory testing has carried out in accordance to the procedures in %S 1077* Part '*1228# on selected samples at various penetrations! The test is including the classification test!

2.(

Subsoil conditions

The interpreted subsoil profiles showing the SPT+ values, ma(orminor classified subsoil components and /ock Guality ;esignation "/G;# are presented in %orehole log provide by 9umpulan 4kram Sdn %hd! /esult obtained from %3 1, %3 ' and %3 0 was used in the subsoil analysis! The main types of soil based on %ritish Soil Classification Systems present in this point are ver4 soft #arine 6L*7! The SPT+ value is very low up to 17!8m with the range SPT+ D 8 to 5 blow088mm! $fter that the SPT+ value increase with depth and the borehole was terminated at depth of '=!8m to '7!8m"SPT+ H 58#! 4t represent that the top soil layer is very loose and possibly it is not well compacted during the construction of the failed slope!

9able 2.1: Soil profile Layer 1 ' 0

(i)

General soil description Iery soft marine clay Sandy silt  sand Sandy silt

epth range !m" 15+1B '0+'6 08

:ayer 1 J Iery Soft Marine Clay This layer represents the upper layer of the original ground and comprises of Iery Soft Marine Clay! The depth of this stratum ranges between 15m to 1Bm with SPT "# values of 8 + 7 blows per 088mm of penetration!

1'


"ii#

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:ayer ' J Sandy S4:TS$; Fnderlying the above is SiltyClayey S$; having depth range between '0m to '6m with SPT "# values ranging between 18 and 58 blows per 088mm of penetration!

"iii#

:ayer 0 J SandyS4:T 3ard layer which SPT "# values of 58 blows per 088mm encounter at depth of H'=m!

10

Cadangan Pembinaan dan Baikpulih Tembok Penahan Sungai Muar di Pekan Panchor, Muar, JohorConsult Sdn. Bhd.

-;isting Soldier
1#

Sungai Muar

er4 Soft #arine 6L*7 Sand4 SIL9 8 S*0D Sand4 SIL9

Figure 2.2: Soil profile

1=


2.=

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"eotecnical interpretation

Several laboratory tests were conducted to determine the properties of the soil! 4t is include the physical and chemical properties of soil! The laboratory test is conducted based on the %S 1077* Part '* 1228!

The consistency limits "li)uid limit, plastic limit and plasticity index# were determined using cone penetrometer test! uid li#it !LL' is ==. ?, plastic li#it !PL' (%. ? and the plasticit4 inde; !PI' 1= ?. Therefore, it shows that the soil is very li)uid with low plasticity index!

Trixial compression test "C4F# conducted to determine the strength coefficient of soil, cohesion and angle of shearing! These two parameters are to be used in the design and also for slope stability analysis! /esults obtained from the test are as follows*+

a'

La4er 1 @ Fir# Sand4 SIL9 γ b

D 15!8 km0

CE D 7 kPa '

φ D 18K

b'

La4er 2 @ Aard Sand4 SIL9 γ b

D 17!8 km0

CE D 18 kPa '

φ D '7K

c'

La4er ( @ Sand4 SIL9 γ b

D 12!8 km0

CE D 1' kPa '

φ D '2K

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Chemical test also being conducted on the soil sample, but there is no evidence soing te presence of ce#ical in the soil! %eside that, particle si&e distribution test also was conducted to classify the soil samples! Particle si&e distribution has been conducted based on %ritish Standard "%S 1077* Part '* 1228#! The soil samples from borehole 0 "%3 0# has been used which two samples at different depth has been tested!

The soil samples at depth =!58 m to =!25 m shows that the soil generally SIL9 !BC.B( ?#, then follows by Clay "'1!B0 L#, sand "'8!=0 L# and -ravel "1!'1 L#!
'!5

*nal4sis of possibilities caused of failure

The analysis caused of failure is being carried out by looking into several possibilities that might contribute to the failure of the slope! 4t has been done by looking into the condition of the soil "theoretical analysis# and also by adopting the stability analysis "numerical analysis#! The teoretical anal4sis is basically based on the result obtained from laboratory testing, on the geotechnical parameters of the soil stratum! Nn the other hand, SL/P- < analysis has been used to analy&e the stability of the slope before failure and after the stabili&ation measures has been taken! The slope failure is confined between C3 =8 m and C3 25 m!

aturally, riverbank is one of the critical areas which the possibilities of slope failure to occur are high! 4n the case of Pekan Panchor, the subsoil condition is also the ma(or factors that might contribute to the failure of slope! %ased on the observations during site investigation, it has been found that the failure envelope is mainly at the layer of Soft Marine 6L*7! The 15 m soft marine clay and loading at the upper slope induced a shear failure at extreme low tie where the instability spread creating a ma(or flow slide! There was a differential head of ' to 0 meter of water between the low tie and high tie! 3ence initiated the flow slide move directly downslope to the river as shown in
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Figure 2.(: Slope surface failure

Several studies have been done by number of researchers on the behavior of soft marine clay and its contribution to the slope failure! Marine clay is sensitive to some degree, and it is more likely to strain+softening not perfectly+plastic "$ndresen and ostad, '887#! The slope failure caused by strain+softening behavior can be explained by considering the progressive failure mechanism!
Figure 2.=: ,otational progressive failure #ecanis# in a slope !valstad et al.$ 2%%B'

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The strains increase further after local failure and the shear stresses reduce from the peak strength towards the residual strength! The capacity "failure load# is increased deformations post peak, a fully developed failure surface eventually forms where residual strengths have been reached along the entire surface! Therefore, after several progressive increments in loading and stresses the slope eventually failed!

Slope  analysis has been adopted in order evaluate the available factor of safety of the existing slope condition against lateral slip failure! This analysis is mainly based on the limit e)uilibrium modeling! The back analysis is conducted at slope of C3 '58! The analysis is focusing on the changing of tie water level which consider as one of the factors that might contribute to the slope failure! The parameters used in this analysis are*+

9able 2.2: Soil para#eters used for anal4sis :ayer 1 ' 0

γ "km0#

;escription Marine Clay 3ard Sandy S4:T Sandy S4:T Traffic :oad

15 17 12

CE "kPa# 7 18 1'

φ E "K#

:oad "km'#

18 '7 '2 18

The factor of safety used is as recommended by the -eotechnical Control Nffice, 3ong 9ong, 12B=!
9able 2.(: ,eco##ended factor of safet4 for ne slopes !after "eotecnical 6ontrol /ffice$ Aong ong$ 1&='.

-cono#ic risk egligible

0egligible H1!8

,isk to life Lo 1!'

:ow

1!'

1!'

1!=

3igh

1!=

1!=

1.=

Aig 1!=

1B


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"a#
"b# 1 m water level

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"c# ' m water level

"d# 0 m water level

Figure 2.B: ,esult of Slope < anal4sis on failure slope

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The results of the back analysis "Slope # conducted on C3 '58 is tabulated in terms of minimum factor of safety against basal failure of the slope "refer Table '!=#!

Case 1 ' 0 =

;escription .xisting profile with full water level .xisting profile with 1 m water level .xisting profile with ' m water level .xisting profile with 0 m water level

Minimum
Aeav4 rainfall and surface E subsurface drainage failure also the other factors that might contribute to the failure! Most of the event of slope failure in this country is due to the rainfall! The true mechanism of rainfall induced failure must be clearly understood! ater infiltrate into the soil will reduce the suction in the soil, therefore it will reduce the shear strength of the soil! Nn the other hand water will make the soil heavier, therefore it will increase the disturbing factor that might cause failure! $s the shear strength of the soil decrease, the resisting factor will also decrease! Thus, it will at one point trigger the failure! The eav4 of flo strea# is one of the factors contributing to the failure of this slope!

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Figure 2.C: Failed soldier all tie it ,6 pile !1B%## ; 1B%##'

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SECTION 3 DESIGN

(.1

Introduction

'0


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There are several types of earth retaining structures available for the purpose to reinstate the failed slope! 4t is including*+ a#

Sheet pile

b#

%ackfilled wall

c#

-eogrid wall with pilling

d#

ellguard wall with tie back system

e#

Soil reinforcement and anchoring

f#

Nthers related system

4n this purposes of pro(ect slope repair, the method that has been considered is ancored seet pile all! Sheet pile is a method of earth retaining structures suitable to be used in an area with high water table and limited construction space! 4n this pro(ect, the failure area is located near to the r iver body which means water table is very high! Therefore, the application of sheet pile is highly acceptable!

(.2

Seet pile

Seet piling is a manufactured construction product with a mechanical connection interlock at both ends of the section! These mechanical connections interlock with one another to form a continuous wall of sheeting! Sheet pile applications are typically designed to create a rigid barrier for earth and water, while resisting the lateral pressures of those bending forces! The shape or geometry of a section lends to the structural strength!

Sheet piling is classified in two construction applications as below> 1#

Per#anent Structure + application is Ostay+in+placeO where the sheetpile wall is

driven and remains in the ground! '#

9e#porar4 Structure + application provides access and safety for construction in

a confined area! Nnce the work is completed, the sheets are removed! Sheet pile walls are usually used in soft soils and tigt spaces! Sheet pile walls are made out of steel, vinyl or wood planks which are driven into the ground!
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estimate the material is usually driven 10 above ground, '0 below ground, but this may be altered depending on the environment! 9aller seet pile alls ill need a tie3back ancor$ or dead3#an placed in te soil a distance behind the face of the wall, that is tied to the wall, usually by a cable or a rod! $nchors are placed behind the potential failure plane in the soil! 4t is very important to have proper drainage behind the wall as it is critical to the performance of retaining walls! ;rainage materials will reduce or eliminate the hydrostatic pressure and will therefore greatly improve the stability of the material behind the wall, assuming that this is not a retaining wall for water! 0!1!1

Common type of sheet pile

i#

Tie rods and dead man This type of sheet pile is usually use as a permanent structures of retaining wall! The sheet pile has been tied by using rod and the concrete block been used as an anchored!

Figure (.1: 9ie rods and dead #an

ii#

Tie rods and anchored wall This type of sheet pile is used mostly at very limited area for construction! Two sheet pile has been installed at both end, which one act as retaining structure while the other one as anchored!

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Figure (.2: 9ie rods and ancored all iii#

Tiebacks with grout anchor The concrete grout has been used to anchor the rod that tightens the sheet pile!

Figure (.(: 9iebacks it grout ancor

The sheet pile of tie rods and ancored all has been selected to be used in this pro(ect! This type of sheet pile is found suitable to be used as it is very effective solution for the tight construction space and re)uired less time for installation!

'6


0!1!'

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Conceptual design of Sheet Piling

;esign of sheet piling is based on a factor of safety for stability applied to soil strengths! 3owever, there is several kind of factor of safety available which given different definitions towards the stability of structures! This is including*+

i#

ii#

iii#

iv#

To avoid compounding factors of safety, the sheet piling and wales are designed to resist forces produced by soil pressures calculated using a factor of safety of 1 for both passive and active pressures!

0!1!0

$nchor system

The construction of sheet pile is considered more effective with the installation of anchor! Permanent sheet pile usually designed with anchored to increase the ability to withstand the load and stress! 4n this slope repair and reinstate pro(ect, the anchor used is an economical anchoring for $ piles!

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Figure (.=: Detail of ancoring s4ste#

The economic advantages are obvious*+ a#

of+centre fixing of wailings with a single bolt reduces material bolt reduces material and installation costs,

b#

off+centre positioning of tie rods makes it possible to use plain bearing plates, and having a hole in the flange rather than through the interlock means achieving effective waterproofing ceases to be a problem!

0!1!=

$rrangement of sheet pile

'B


(.2

Consult Sdn. Bhd.

,etaining eart structures design

The design of this particular sheet pile is based on limit e)uilibrium method!

Sheet pile detail geometry

18 km'

%ackfilled

'!5 m 5m

$nchor

Soil 1

1' m

Main sheet pile

Figure (.C: Seet pile detail geo#etr4 Soil '

dE m

Soil profile parameters

9able (.1: Soil profile para#eters Soil %ackfilled

escription 5 m backfill soil for temporary working platform and permanent road

Parameters γ b D 17 km 0 CE D 8 kPa φ E D 08K

Soil 1

D 15 km 0 CE D 7 kPa φ E D 18K

Soil '

3ard sandy S4:T

D 17 km 0 CE D 18 kPa φ E D '7K

γ b

γ b

Step 1 .arth pressure coefficients

'2


$ssume

σ aE

D

1 2

φ E, σ h D

2 3

φ

Consult Sdn. Bhd.

'

.arth pressure The earth pressure calculation has been done to determine the embedment depth of sheet pile!

Take moment about f to determine the depth of penetration*+

∑ M D 8 0!275 x ' "'' Q1=QdE# Q "=7!=77+0!275# x ''"'0 Q1=QdE# Q =7!=77 x 1 "1'Q10QdE# Q "67!'7= J =7!=77# x R "10 Q10QdE# Q 50!=B7 x '"''Q10QdE# Q"5B!706 50!=B7# x R x "10Q1'QdE#Q "5B!706+10!067#1'' x "10QdE# Q 10!067 x 1' x "1''QdE# D 8

112!'5 Q 7!25 dE Q 60B!80 Q =7!=77 dE Q 08B!68 Q =7!=77 dE Q 101!B Q 2!2 dE Q=27!6= Q 186!27 dE Q 0'!062 Q '!6'5 dE Q 28!70B Q =77!'1= dE Q 26'!= Q 0B8!=8= D 8

'51=!5'5 D 275 dE dE D '!572 m

Therefore, it is found that the depth of penetration is to be*+ 8!888 m

dE D '!572 m

≈

0!8 m '!888 m

Thus, the total length of sheet pile wall is '8!888 m!

0!888 m =!888 m

Total pressure diagram 0!275 16!888 m

08 12!572 m


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=7!=77 50!=B7

67!'7= 5B!706

+'66!'82

10!067

+0=6!7B2 Step 2

Maximum bending moment

Maximum bending moment occur at &ero shear force!

Shear force diagram 8!888 m 8!888 '!888 m +'76!785

0!888 m =!888 m

+'12!008

+160!'1B

16!888 m '62!027

+62B!=77

01 12!572 m


Consult Sdn. Bhd.

Bending moment diagram 8!888

8!888 m

'!888 m

+1'2!550

0!888 m =!888 m +578!20'

7!888 m

+B10!'B2

7='!616

%ending moment for the sheet pile wall is*+

17!888 m

12!572 m

8!888 Maximum D 7='!616 k!m at 16!278 m

Minimum D +B10!'B2 k!m at 7!8 m

0'


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Maximum anchored force D 010!680 km "increase by 18L to allow for hori&ontal arching#

Step ( Proposed sheet pile dimension  detailing

:ength of sheet pile D '8 m with maximum moment of 7='!616 k!m, then provide*+ Section modulus D '=58 cm 0m Steel grade D 055 mm '

Step = $nchor

The loading cases adopted for tie back sheet pile*+ i#

The first with the reaction from the main wall "anchorage force#

ii#

The second, ultimate limit state, in which the reaction form the main wall "anchorage force# is multiplied with a safety factor of 1!5!

$t '!8 m cc Maximum anchor force D 010!680 km $nchorage load D 010!680 x '!8 D 6'7!'86 k  7B' k

Thus, the tie rod re)uired is 1 at '!8 cc sheet pile wall!

Step B aler design Maximum moment on waler D D

wl

2

10

313 .603 x 2.0

2

10

00


Consult Sdn. Bhd.

D 1'5!== kmm

Choose C channel, ' nos of 088 x 28 x =0!B kgm

Section modulus D =2= cm 0, grade 055 mm ' Moment capacity allow D

2 × 494 × 355 1.5 × 1000

km

D '0= kmm "H 1'5!== kmm#

(.(

Spun pile

The existing road was damaged due to the event of slope failure! Therefore, based on the scope of pro(ect work the damage road has to be repair! 4t is found that the road base is very weak due to the presence of very soft marine clay! The installation of pile is adopted in order to improve the ability of ground to sustain the load from road!

Generali#ed soil profile Spun pile "'58 mm dia#

15 m

2m

DB

 D '5

Iery soft marine clay

The spun pile was designed to cater the traffic load form the existing road! Therefore, Clay S4:T number of pile installed is meant for sustain the imposed load from the road only! The pile installed is*+ 0=


Consult Sdn. Bhd.

:ength D 1' m at ' m cc ;iameter of pile D '58 mm  "refer to detail calculation in appendices#

(.=

*dditional slope stabili)ation #easures

$dditional slope stabili&ation measures have been taken to protect the slope from erosion caused by moving river water! There is the case back during serious flood in 1226, where the riverbank is collapsed due to the erosion caused by moving river water! Therefore, proper remedial works are necessary to avoid further extent of failures!

The use of a#our rock is essential to prevent the slope from erosion! 4t will work to protect the slope surface and sow down the velocity of the water! $mour rock is in form of solid rock which in si&e of 18E to '8E and it is coherent rock which does not softening due to expose to water! The suitable type of rock which can be used as amour rock is such as granite, limestone and basalt! 4n this pro(ect, granite has been chosen due to the availability and the cheaper cost!

The geote;tile has to be layered on the river bed before place the amour rock! -eotextile is used as separator to separate the amour rock and the soil! %eside that, it also works as filtration and reduce the possibility of erosion to occur!

Sheet pile wall

ii#

$nchored sheet pile wall

iii#

Spun pile

iv#

$mour rock

v#

-eotextile

The detail slope remedial work is as shown in appendices!

05


Consult Sdn. Bhd.

06

Cadangan Pembinaan dan Baikpulih Tembok Penahan Sungai Muar di Pekan Panchor, Muar, JohorConsult Sdn. Bhd.

$nchored Sheet pile Tie rod Spun pile Sheet pile wall -eotextile "
Figure (.G: Proposed slope stabili)ation

07


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SECTION 4 ANALYSIS – SLOPE/W

0B


=.1

Consult Sdn. Bhd.

Introduction

The analysis of proposed slope stabili&ation has been done using -eo Studio software! This software is including the analysis of slope using Slope+ analysis! Slope+ is a program which suitable to be used as to analy&e the stability of the slope! The numerical analysis is the idea of discreti&ing a potential sliding mass into slices, which means the analysis is a process to determine the failure plane for very small slices of sliding mass!

=.2

Slope anal4sis b4 using SL/P-8<

The proposed continuous sheet pile wall with tie back has been analy&ing using Slope+  program!
P,/P/S*L F/, ,-M-DI*L
05 =5 07 06 '2 17 08 7=0

08

=6 =1 0= 6

0'

=8 ='

0B

== 16

08Description: Marrine CLA

1=

15

!t: "#

6

'5

'5Cohesion:

5

'

m'8 , n o i t a 15 v e l .

7

5 01

0

00

05

= '7

0

'8 =7

02

'5

B

=

''

18 11

'=

1'

'0

Description: CLA !t: "$ Cohesion: "0 %hi: &$

18

'8 12 '1

5

15

'6

'B 1B '1

18

$

%hi: "0

2 5

1

10

Description: 'ar( CLA !t: ") Cohesion: "& %hi: &)

8 8

'

=

6

B 18 1' 1= 16 1B '8 '' '= '6 'B 08 0' 0= 06 0B =8 =' == =6 =B 58 5' 5= 56 5B 68 6' 6= 66 6B 78 7' 7= 76 7B B8 B' B= B6 BB 28 2' 2= 26 2B 188

18=

8 18B

;istance, m

Figure =.1: Diagra# of proposed re#edial ork

02


Consult Sdn. Bhd.

P,/P/S*L F/, ,-M-DI*L
1!=05

05

05

=5 0706 '2 17 08 7=0

08

=6 =1 0= 6

0'

1=

15

=8 ='

0B

== 16

Description: Marrine CLA !t: "# '5 Cohesion: $ %hi: "0

6

'5

5

'

m'8 , n o i t a v e 15 l .

7

5 01

0

00

05

= '7

0

'8

=7

02

'5 15

'6

1B ''B 1

18

B

=

''

18 11

'=

1'

'0

2 5

1

10

8 8

'

=

6

Description: CLA !t: "$ Cohesion: "0 %hi: &$

18

'8 12 '1

5

08

B 1 8 1 ' 1= 1 6 1 B '8 ' ' ' = '6 ' B 0 8 0' 0 = 0 6 0B = 8 = ' = = =6 = B 5 8 5' 5 = 5 6 5B 6 8 6 ' 6= 6 6 6 B 78 7 ' 7 = 76 7 B B 8 B' B = B 6 BB 2 8 2 ' 2= 2 6 2 B 1 88

1 8=

8 1 8B

Description: 'ar( CLA !t: ") Cohesion: "& %hi: &)

;istance, m

Figure =.2: Slope < anal4sis of proposed re#edial ork

%ased on the analysis that has been done, the factor of safety of the slope is increase to 1!=05 at the water level 0 m! The back analysis that has been done before suggested that the slope is failed at the water tie of 0 m with factor of safety 8!266! 4t is suggested that the slope stabili&ation is increase the stability of the slope! The installation of sheet pile wall is ultimately increased the factor of safety and control the failure plane of the slope!

=.(

Slope < anal4sis of e;isting slope stabili)ation

=8


Consult Sdn. Bhd.

The consultant of the pro(ect has proposed the wellguard wall with piling! ellguard wall is basically use the 4+beam instead of sheet pile which been installed with the ground anchor! The wellguard wall panel is connected to 4+beam using capping beam! This method of stabili&ation is basically similar to the sheet pile wall system!
,-M-DI*L
Figure =.(: Diagra# of e;isting re#edial ork

,-M-DI*L
=1


Consult Sdn. Bhd.

Figure =.=: *nal4sis of e;isting re#edial ork

=.=

*nal4sis of finding

The results of this back analysis conducted for two locations namely C3 '58 at the site! The results are tabulated below in terms of minimum factor of safety against basal failure of the slope!

9able =.1: Factor of safet4 for proposed and e;isting slope stabili)ation 6ase

Description

Mini#u# F./.S.

/emedial ork 1

Sheet Pile with tie back and piling

1.=(B

'

ellguard wall with piling

1.(G

%ased on the result tabulated in Table =!1, it shows that both of slope stabili&ation scheme is well improved the stability of the slope after the event of failure! The factor of

='


Consult Sdn. Bhd.

safety of sheet pile with tie back is slightly higher than the wellguard wall with piling! Therefore, both options can be used as to improve the stability of the slope! The total cost of the pro(ect then can be used as to determine the best option for slope stabili&ation and remedial work!

SECTION 5 =0


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COSTING

B.1

Preli#inar4 6ost -sti#ation

The preliminary cost has been done to estimate the total cost of the pro(ect including the preliminaries work, site investigation, remedial work, material cost and other additional work!

B.1.1 6ontinuous Seet Pile
9able B.1: 9otal cost of 6ontinuous Seet Pile
D-S6,IP9I/0

1 '

Preli#inaries ork ,e#edial
9/9*L !,M' '1=,708!88 156,888!88 1,'5=,=88!88

==


iii# Spun Pile

0 =

iv# /oad Pavement v# /iver Slope Protection Drainage 9urnke4 -le#ent i# Consultancy ii# Site 4nvestigation 9/9*L

Consult Sdn. Bhd.

01',258!88 '18,888!88 '62,188!88 08,888!88 118,888!88 =8,888!88 2$B&G$1%.%%

Table 5!1 represent the preliminary cost for remedial work using sheet pile with tie back system! The work is including the installation, monitoring, and site clearance! The total cost is provisional to change and it is depend on the market material price!

B.1.2

The existing slope remedial work is adopting the option of wallguard wall with piling! Table 5!' shows the preliminary cost of the remedial work! The total cost is including material price, site investigation, remedial work and also the consultancy work!

9able B.2: 9otal cost of allguard all it piling 5ILL 0/ 1 '

0 =

D-S6,IP9I/0 Preli#inaries ork ,e#edial
9/9*L !,M' 12B,B18!88 156,888!88 1B5,888!88 01',258!88 '18,888!88 '62,188!88 015,888!88 661,288!888 08,888!88 118,888!88 =8,888!88

=5


9/9*L

B.1.(

Consult Sdn. Bhd.

2$=GC%.%%

6o#parison of proposed re#edial ork

%oth of the remedial work relatively has advantages and disadvantages respectively! The analysis of advantages and disadvantages is important as to select the best remedial work at the reasonable cost!

9able B.(: 6o#parison of proposed re#edial ork ,e#edial ork Sheet pile with tie

6ost /M ',527,1B8!88

back system

*dvantages i# .asier to construct!

Disadvantages i# Steel expensive

ii# Shorter construction time iii# /e)uired minimum

ellguard wall with piling

/M ',=BB,768!88

construction space i# /elatively easy

i# .xpensive

construction method ii# Shorter construction time

=6


Consult Sdn. Bhd.

SECTION 6 METHOD OF STATEMENT

=7


C.1

D,II0" M-9A/DS

C.1.1

Pitc and Drive Metod

Consult Sdn. Bhd.

This method re)uires e)uipment to control the verticality of the pile during installation so that piles can be pitched and driven one by one! The pitching operation can be carried out do e to ground level meaning that operatives are potentially at less risk and downtime windy conditions can be reduced!

Piles can be installed to final level by this method "necessary when using the apanese presses with single piles# or left at a higher levelto backdrive using panel driving techni)ues with other, generally heavier, hammers to speed up production or drive accurately in deeper more difficult strata! This method is the simplest way of driving piles but is only really suited to loose soils and short piles!
4n recent years, the method has become more favored by installers as purpose built e)uipment is now available to ade)uately control the pile during installation! 4n the right conditions productivity is maximised! 4t is more difficult to control forward lean using the pitch and drive method because the leading lock has less resistance than the trailing or connected lock as a result of soil and interlock friction, $lthough the piling may commence from a true vertical position, the top of the piles will have a natural tendency to lean in the direction of driving! This will get progressively worse if not countered hen

=B


Consult Sdn. Bhd.

driving long straight sections of wall with a planned pitch A drive method it may be advisable with the .ngineers consent, to allow for supplying prefabricated tapered correction piles for use at approximately fifty metre intervals! This is important to consider when using the apanese pressing machines because it may not be possible to revert to a panel backdriving system to avoid or correct the forward lean problem!

ith pitch and drive, the free leading interlock is constantly in danger of rotation in plan which increases the deeper the free end penetrates the ground as it is unsupported

during the driving operation hen a pile rotates during installation, friction develops in the connected locks making driving progressively more difficult!

C.1.2

Panel Driving Metod

Piles may be threaded together above the ground in a support frame to form a panel prior to driving! 4n this situation, both interlocks are engaged before any driving takes place and this balancing of the friction forces ensures maximum control and accuracy! The piles are then driven in stages and in se)uence into the ground! Se)uential driving enables verticality to be maintained!

Sheet piles should be installed using the panel+driving techni)ue to ensure that good verticality and alignment is achieved and to minimise the risk of driving difficulties or declutching problems! This techni)ue is important for maintaining accuracy when driving long piles or driving into difficult ground!

$s a whole panel of piles has been pitched there is no need to drive all piles fully to maintain progress of the piling operations ;uring driving the tops of ad(acent piles can be kept close together meaning that the stiffness of the piles is maintained across both connected locks allowing the pile toe to be driven through soil of greater resistance without undue deviation!

4f obstructions are encountered, individual piles can be left high without fear of disruption to the overall efficiency of the installation process .ngineering decisions can then be

=2


Consult Sdn. Bhd.

taken to attempt to remove the obstruction or drive piles carefully either side of the obstruction before trying once more to drive or punch through it if further penetration is necessary!

Panel driving is the best method for driving sheet piles in difficult ground or for penetrating rock + which is unlikely to be possible with the pitch and drive method Piles are usually paired up or neighboring sheets leveled up at the head before commencing the hard driving operation with a ieavier lammer, Care should be taker when piles are firstly pitched and installed in singles and driven in the first stage with a vibrohammer 4t is easier to execute two stage driving in pairs if the pies are pre ordered and installed in

crimped pairs, ;ifficulty of pairing up in the panel is avoided in this way and safer more efficient operation of impact hammers can be ensure!

58


Consult Sdn. Bhd.

Figure C.1: Panel driving #etod

C.2

D,II0" S7S9-MS *0D 97P- /F A*MM-,

The choice of a suitable driving system is of fundamental importance to ensure successful pile installation with due regard to the safety of operatives and environmental disturbance

The three basic driving methods are*+

4mpact drving This is the best method for driving piles into difficult ground or final driving of piles to level in panel form, ith a correctly selected and si&ed hammer it is the most effective way of completing deep penetration into hard soils in most conditions The downside is that it can be noisy and not suitable for sensitive or restricted sites

Iibrodriving This is usually the fastest and most economical method of pile installation but usually needs loose or cohesionless soil conditions for best results Iibration and noise occurs but this can be kept to a minimum provided the right e)uipment is used and the site is not too sensitive

Pressing Ntherwise known as silent vibrationless hydraulic (acking! Machines of various types are now widely used This method is very effective in clay soils but less so in dense cohesionless ground unless pre+augering or (etting techni)ues are used, This is the most effective method to use when installing sheet piles in sensitive locations where piling would have not been considered in the past

C.2.1

Site 6onditions

51


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The local environment of the site will influence working restrictions such as noise and vibration .ach site will be sub(ect to i s own uni)ue set of restrictions which varies according to the proximity and nature of neighboring buildings, road category, underground service power supplies, material storage areas etc! -eological conditions refer to the vertical characteristics of the soil strata 4n order to achieve the re)uired penetration of the sheet piles, site investigation of the soils together with field and laboratory tests can aid installation assessment by providing information on*

a# stratification of the subsoil b# particle si&e, shape distribution A uniformity c# inclusions d# porosity and void ratio e# density f# level of the groundwater table g# water permeability and moisture content of the soil h# shear parameters, cohesion i# dynamic and static penetrometer test results and results of standard penetration or pressuremeter tests,

C.2.2

Driving S4ste# 6aracteristics /n arious Soils

;ifferent types of soil present varying driving characteristics dependant upon the driving system to be adopted! %rief notes on each system are given below

4mpact ;riving .asy driving may be anticipated in soft soils such as silts and peats, in loosely deposited medium and coarse sands and gravels provided the soils free from cobbles, boulders or obstructions! ;ifficult diving may be expected in densely deposited fine, medium and coarse sands and graves, stiff and hard lays, "depending on the thickness of the strata# and soft+medium rock strata,

5'


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Iibratory ;riving /ound+grain sand and gravel and soft soils are especially suited to vibratory driving .asy driving should be expected when soils are described as loose! ;ense angular+

grain material or cohesive soils with firm consistency are much less suited! ;ifficult driving may be experienced when dominant SPT values are greater than 58 or significant thicknesses of cohesive strata are encountered

4t is also found that dry soils give greater penetration resistance than those which are moist, submerged or fully saturated 4f the granular subsoil is compacted by prolonged vibrations then penetration resistance will increase sharply leading to refusal!
Pressing This method is especially suited to soils comprising cohesive and fine material! .asy driving is usually experienced in soft clays and loose soils! This techni)ue usually employs (etting assistance to loosen silt and sand particles in cohesionless strata to be able to advance the piles by pressing! Successful installation will also depend on the soil providing cohesive adhesion to the reaction piles!

;ifficult soil conditions are found when dense sands and gravels or soil containing cobbles or any large particles + which would make (etting ineffective + are encountered! hen boulders or rock are encountered, reaction failure or refusal may occur :ead trenches may be of assistance for the removal of obstructions encountered near the surface!

4n these circumstances pre+augering is usually necessary to be able to adopt the pressing techni)ue> otherwise piles will have to be driven to final level by percussive means! et soil conditions are also favorable for pressing! 4n dry, stiff clay strata, it is normal practice to use low pressure (etting to lubricate the soil to pile interface and make driving easier!

50


C.2.( C.2.(

Consult Sdn. Bhd.

Influe Influenc nce e /f Met Metod od /f /f Insta Installa llatio tion n

4t is also very important to consider the installation techni)ue to be used Pitch and drive "PA;# "PA;# method methods s will will reduce reduce the driveabi driveability lity!! hen hen silent silent pressing pressing using using apane apanese se hydrauli hydraulic c (acking (acking machines, machines, the stiffness stiffness of the pile is of paramou paramount nt importan importance ce to maximi&e driveability as the machine operates on pure PA; methods!

.xperience of driving sheet piles enabled relationships to be developed to assess the driveability of particular profiles! Nne such relationship used the section modulus of the pile profile as the key factor! 3owever, it is not possible to derive the most suitable choice of pile section by consideration of section modulus alone The section re)uired to be commerci commercially ally effecti effective ve and successf successfully ully installe installed d depend depends s on conside consideratio ration n of a number of factors and the following selection procedure is recommended*

5=


Consult Sdn. Bhd.

Figure C.2: Selection procedure of pile section

C.( C.(

I0S9 I0S9* *LL* LL*9I/0 I/0 /F SA-SA--9 9 PIL PIL- 5*S 5*S-D -D /0 /0 P,/ P,/HH-69 69

%asically above explain the method of installation of sheet pile and which are the best methods to install install sheet pile form the variety variety of choices in the market! market! Meanwhile Meanwhile in this section, explains briefly the stages that to be undergo in order to do the re+habilitation works for the pro(ect!

There are B stages for the re+habilitation work! The stages are as follows *

•

Stage 1 J 4nstall 6m continuous sheet pile as temporary protection

•

Stage ' J .xcavation and backfill crusher aggregate as working platform

•

Stage 0 J 4nstall '58mm dia! spun pile at 'm cc and construction of pile cap!

•

Stage = J :ay a layer of geogrid -U 68858 and backfill with sand!

•

Stage 5 J /emoval of exiting retaining wall!

•

Stage 6 J 4nstall '8m length of continuous sheet pile wall

•

Stage 7 J Tie back '8m continuous sheet pile wall with 6m continuous sheet pile wall!

•

Stage B J Sand and fill until existing road level and construct river protection with amour rock!

55


Consult Sdn. Bhd.

S9*"- 1 S9-P 1

1#

Sungai Muar

er4 Soft #arine 6L*7

S*0D 6la4e4 SIL9

S9-P S9-P 1 + 6m lengt length h of tempo temporar rary y contin continuo uous us shee sheett pile pile wall wall is insta installi lling ng throu through gh pressure system! This sheet pile is installing along the alignment of the road "68m#! This temporary sheet pile is to prevent any slope failure from happening which could affect the building located 5m away from the edge of the road!

56


Consult Sdn. Bhd.

S9*"- 2

Step 2 Step (

1#

Sungai Muar


S*0D 6la4e4 SIL9

S9-P 2 + .xcavation of 'm depth is done and the excavated material will be removed from site! S9-P ( + Crusher run of 588mm thickness is lay on the excavated platform! The crusher run is placed in order to give a working platform when the remedial works is done and to prepare a flat platform to ease the spun pile work!

57


Consult Sdn. Bhd.

S9*"- (

Step = 1#

Sungai Muar


S*0D 6la4e4 SI

S9-P = + '58mm diameter of spun pile is install at 'm cc! The working load of the spun pile is =8k! $fter the pile is install the pile cap will be constructed!

5B


Consult Sdn. Bhd.

S9*"- =

!

Step B

Step C 1#

Sungai Muar


S*0D 6la4e4 SIL9

S9-P B + $ layer of geogrid -U 68858 is layed after the pile cap have been constructed S9-P C + $fter the geogrid have been lay, 588mm thickness of sand will be lay! This layer then is being compacted!

52


Consult Sdn. Bhd.

S9*"- B

Step G 1#

Sungai Muar


S*0D 6la4e4 SIL9

S9-P G + The existing retaining wall will be removed after the sand compaction works have been completed!

68


Consult Sdn. Bhd.

S9*"- C Step  1#

Sungai Muar


S*0D

6la4e4 SI

S9-P  + 4nstallation of '8m continuous sheet pile wall will be carry out along the 68m road using the pressure system after the removal of existing retaining wall have been completed

61


Consult Sdn. Bhd.

S9*"- G

Step &

Sungai Muar


S*0D 6la4

S9-P & + $fter the '8m continuous sheet pile wall have been installed a tie back is done using tie rod and 4+%eam between the 6m sheet pile wall and '8m sheet pile wall!

6'


Consult Sdn. Bhd.

S9*"- 

Step 1( Step 12 Step 11 1#

Step 1%

Sungai Muar


S*0D 6la4e4 SIL9

S9-P 1% + 4nstall a layer of <+
60


Consult Sdn. Bhd.

S$CT%&' ( M&'%T&)%'G *' %'ST)+M$'T*T%&'

6=


Consult Sdn. Bhd.

G.1 Monitoring and instru#entation Monitoring and instrumentation process has been developed to monitor the possible amount of movement of sheet pile wall with tie back system slopes during construction as well as after the completion of construction! The monitoring can provide useful information for the following purposes*+ i#

safety during construction, allowing construction procedures to be modified

ii#

developing economy in the design

iii#

obtaining an idea of the behavior of the soil+nailed structures

iv#

Providing insight into maintenance re)uirements by long+term performance monitoring for permanent applications!

The monitoring and observation programme will includes i#

hori&ontal movement of facing

ii#

vertical movement of surface of overall structure

iii#

local movements or deterioration of the facing

iv#

groundwater levels

v#

drainage behavior

Table 7!1 show the summary of monitoring instrumentation used in this pro(ect!

9able G.1: Su##ar4 of #onitoring instru#entation Parameter 3ori&ontal movement Iertical movement -roundwater

4nstruments Surveying methods 4nclinometers Surveying methods .xtensometers Pie&ometers

65


Consult Sdn. Bhd.

S$CT%&'  C&'CL+S%&'

66


.1

Consult Sdn. Bhd.

6onclusion

The selection of remedial work is has to be based on the effectiveness of the method and also the total cost of the pro(ect! Sheet pile with tie back system is comparatively expensive compared to other method of earth retaining structures, but it is most effective for area with high water table and also the installation  construction period is shorter! This method is re)uired a special e)uipment as to drive the sheet pile to the re)uired embedment depth!

3owever, based on the analysis that has been done it clearly shows that the sheet pile with tie back system is ultimately increased the stability of the failure slope at 0 m water tie! Therefore, by adopting this method of remedial work it can improve the slope stability as well as improve the total strength of the ground

67

Final Report Ers

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