ewpl - s. jayachandra

8/3/2019 EWPL - S. Jayachandra

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OF EWPL CROSSINGSPr e se n t a t i on by :

ayac an ran,Reliance Gas Transportation Infrastructure Ltd.


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EWPL Project and its Challenges Special Crossings Crossing Methodologies

Microtunnel Float and Sink Cofferdam


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East West Gas Pipeline (EWPL) comprise of 1375 km long 48 dia trunk

line from Kakinada, Andhra Pradesh to Bhadbhut, Gujarat; 82 km longspur lines of various diameters from 24 to 30, 11 Compressor

Stations, 6 M&R Stations, 37 MLVs, 4 TOPs, 2 Pipeline Operations

Centers and other associated facilities.

the four years period since 2005.

EWPL Pro ect achieved si nificant distinctions durin the execution

including establishing World Record in HDD and Microtunneling.


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EWPL Pro ect and its Challen es Largest single pipeline project ever undertaken in India

:

Over 800 km of trenching in rock by blasting Over 150 km of marshy and slushy coastal land

Undulating stretches of around 50 km

Over 100 major perennial and tidal water body crossings requiringspecial construction methods.

Construction methods viz. Micro tunnelling, HDD, Float and Sink,Cofferdam and other construction adopted

,river executed by using Microtunneling

World record HDD crossings of 48 diameter pipeline; 1,724 m long,


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EWPL Pro ect and its Challen es

First time use of Cable Crane System for laying of pipeline on steepBhivpuri Ghat; over 1,400 m long stretch with an elevation rise of over500 m

Record mainline welding of X-70 grade line pipes in excess of55,45,000 inch-dia & combined welding of mainline, spur line,

compressor station piping and M&R station piping in excess of-, , .

Completed in 3 years with Project kick off in Dec., 05, Constructionstart in Oct 06, Pre-commissioning in May , 08 and Commercial

.,


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Record number of Crossings viz. Road (NH, SH, MDR, Others),

Railway, Canal, River, Streams, 3rd Party Pipelines, etc.

encountered by Trunkline. In all 1770 crossings were encountered, which is approx. 1.3

Crossings per km of pipeline length

Total HDD Crossings in EWPL is over 8,200 m


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Crossings are the most difficult part of pipeline project execution.

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construction methodology including identification of technologylimitations, careful planning and establishment of additionalinfrastructure.

Resource mobilization of specialized equipment and manpower is achallenging task as additional specialized equipment to tacklecontingency measures also to be mobilised.

Crossing location normally selected during overall pipeline route selection

Selection is done such that the crossing length is minimum, river does not

, , ,adequate space available beyond the banks for constructioninfrastructure .


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es gn comp es . or gas nes an . or qu nes another statutory requirements

Score potential of the river bed established based on sub-soil and y ro og ca survey nc u ng oo ng an e p pe ne oca e . m

below the scour profile.

Pipeline wall thickness and radius of curvature is established based onns a a on an opera ona con ons.

Anti-buoyancy measures required in case of open cut crossings as apermanent measure.

Temporary anti - buoyancy measures also required in case of float &sink or bottom-pull methods to minimise the pulling loads.


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This presentation covers :

World Record Microtunnel Crossing across Gauthami Godavari

World Record HDD Crossing across Vashista Godavari Tapi River Crossing adopting Float & Sink Technique

Terna River Crossing adopting Cofferdam Technique


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HDD


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Crossing located at KP 60.2, Andhra Pradesh State

Length of the crossing more than 2400 m.

HDD option ruled out due to technological limitations at the time of

p ann ng e o .

Other options considered include a pipe bridge and a micro-tunnel.

above-ground structures with high pressure pipeline, decision for micro-

tunnelling made.


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Microtunnelling is a trenchless construction method that pushes the

tunnel pipe into place behind a remote controlled TBM.

enera y s ra g a gnmen a op e . urve a gnmen s m ar o

possible with suitable navigation guidance system and special tunnel pipe

desi n

Curved alignment (both vertical and horizontal) allows longer drives with

fewer shafts and shallower shafts

Gautami Godavari profile incorporates combination of curved and

straight alignment


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Infrastructure Established

Access Roads to Shaft locations

Tem orar Pi e Brid e across an irri ation canal on East side

Hard Stand provided around Shaft Tem orar i e factor for shaft se ments and ackin i es

East Shaft approach road, 2km Center Shaft Approach Road, 1 km Pipe Factory


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Jacking Pipes Production at Pipe Factory

pe ac oryJacking Pipe Cage

Reinforcement in Progress

Cage Mould being Installed

Jacking Pipe, 2.4 m ID, 0.23m thk, 4 m Long,

Jacking Pipe Ready forInstallation


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a ow

ShaftEast ShaftCenter ShaftWest Shaft

East Shaft - 11.1 m dia, 8.5 m deep (Launch)

1304 m 80 m1135 m

West Shaft 11.1 m dia, 9 m deep (Launch) Central shaft 8.8 m dia, 26.7 m deep (Receipt) Shallow shaft 8.8 m dia, 7 m deep (Receipt)


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Shaft with Pre-cast Concrete Segments

Shaft Rings

Soft EyeSoft Eye

Base Slab

Grout


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Shaft Installation

Site Preparation Shaft SinkingRing Segment Placement

Base Slab ConcretingShaft Sinking


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Problems faced during Shaft SinkingWest Shaft :

High water table during sinking

Dewatering system provided to lower the ground water level

Invert level raised by 3 m to avoid heavy seepage

East Shaft :

Invert level raised from 11.0m to 8 m to minimise excavation.

Shallow Shaft :

Originally not planned. Provided to minimise excavation.

Central Shaft :Due to stiff clay layer encountered in the river bed, shaft could

no e owere o e requ re ep an nver eve ra se y m


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Tunnelin O erations Tunnelling operations planned from both east and west banks

simultaneously, so that the activity completed before onset of monsoon.

Two TBMs mobilised to site.

Tunnel driven through silty fine sand, clayey sand, clayey silt and fineto medium sand with traces/ ockets o cla or ravel

Dual mode TBM (EPB 2400 AH) mobilised, which operated on EPB(Earth Pressure Balance) for clayey silt and Slurry mode for sand andravel

TBM cutting head turns during tunnel pipe jacking operation and thecutting tools at the face cut the soil. Soil is pressed through theopening in the cutter head into excavation chamber.

In EPB mode, soil is transported via screw conveyor out of theexcavation chamber to a belt conveyor and into a muck car. Muck carpulled over the rails installed within the tunnel pipes by a hydraulicwinch.


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Tunnelin O erations In Slurry mode, the material is transported via screw conveyor out of

the excavation chamber to a slurry box. Soil is mixed with waterand then pumped through a slurry line to surface via pumps. Pumptransfers the material to a desander where the water from material isseparated.

Jacking is done with the help of 4 no. hydraulic cylinders, 4 m strokelength, located within the launching shaft. Jacking arrangementconnected with hydraulic hose to the control container locatedabove ground near the shaft

Lubrication system comprising of mixture of water and bentonite is

soil


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Tunnelin O erations Intermediate jacking station (IJS) is used to give additional thrust

to push the pipes. Control of i eline ali nment is monitored throu h UNS, ca able

of detecting deviations from planned alignment and level occurring

during jacking operation. Once deviations are detected, the sameis corrected through the steering cylinders at the head of TBM.

Rubber sealant is used between tunnel se ments for water

tightness


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Jacking Pipe

Steel CollarAnchor Rubber Seal

Animation Courtesy Zublin


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TUNNELLING OPERATIONS

TBM Under positioning in

Shaft

Commencement of Tunnelling

Pipe Jacking Setup with Gantry

East ShaftJacking Pipe with Rails and

other Piping for Construction


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Jacking Pipe Lowering, Aligning & Jacking

Jackin Pi e Handlin

Jacking Pipe

Jacks in Operation LoweringJacking Pipe Aligning


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Tunnelin O eration

a owShaft

East ShaftCenter ShaftWest Shaft

1304 m 80 m1135 m


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Intermediate Jacking Station

IJS No.1 IJS No.2 Main Jacks

(Animation CourtesyZublin)


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Lubrication System

Compr. Air

Bentonite Lubrication

Bentonite Valve

(Animation CourtesyZublin)


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PRODUCT PIPE PUSHING OPERATIONS

Original plan was to fabricate the pipe string and push the pipes from both

sides of the river and make a tie-in within the central shaft

Due to time schedule and RoU issues, the plan revised to pushing from one side

of the river i.e. east bank. This eliminated the need for tie-in within the shaft

.

space availability on east bank.

Strings placed on 20 T/ 80 T custom fabricated rollers to minimise pullingefforts

Pipe Thruster from Herrenknecht, Germany mobilised and placed at entry of

shaft for undertaking pushing operations. Need of pulling cables and drum

winch thus eliminatedPipe thruster with 2 no. hydraulic cylinders capable of providing a max

,

angle manufactured for the first time in the world deployed at EWPL site.


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Original lan was to ush the roduct i e into the tunnel using rail-car s stem

This method required precise alignment rail and pipe string.

Due to mis-alignment of rail segments installed within the tunnel, flexibility of

,

getting derailed and pushing could not be continued. Finally this method

abandonedLimited time available before onset of monsoon, improvised method involving

placement of 20 T rollers within the entire length of tunnel considered, which

would not only take higher degree of rail/pipe mis-alignment, but would not

result in pipe falling off the rollers. This method also would minimise thepushing efforts.


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Spare availability of rollers helped in implementing this methodology

Pipe string provided with a cone pull-head helped in tackling the

misalighment of tunnel pipe and still pipe string.

Pushin o 1st strin with Thruster went o smoothl . 2 nd strin rolled over

brought in alignment, welded with 1 st string and pushing continued. Similar

procedure adopted for 3 rd string.

o a eng o e p pe s r ng pus e n o e unne was m.

Post hydrotest completed after Installation of Pipe inside the tunnel

Riser with 6 D bends installed within West Shaft, to bring the product pipe

to the ground level.


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Initial Pipe Pushing Operations

Pipe string on rollers Pipe Thruster inAction

Shallow Shaft EntryProfile

Pipe Pushing inProgress

Tunnel View Prior to

Pipe Entry


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Pipe Pushing Rail Car System

Rail Car being Placed Pipe Lift-off

Rail/wheelMisalignment

Rail Misalignment


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CP system and OFC ducts are laid inside the tunnel prior to product

Pipe installation

To prevent upheaval buckling and for effective Cathodic Protection,.

8 HDPE pipe is laid inside the tunnel for grouting activities

Approx. 52 grout samples prepared with different proportions ofCement, Bentonite, Flyash and Water mix

Grout mix finally adopted consisted of 150kgs Cement + 400kgs Fly

as + gs en on e + s wa er

Set up for Grout mix plant consisted of 4nos Steel mixing tanks, 10

Pum s (Mixin +Char e+Transfer) , A itators, and manual labour


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Infrastructure works commenced in May, 2006

Site development and pipe factory works commenced in June, 06

Shaft construction started in Nov 06 and completed in April 07

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respectively to complete

Tunneling commenced in January 07 and completed in May 07Tunnel from East to Central Shaft (280 pipes), West to Central Shaft

(324 pipes) and East to Shallow Shaft (12 pipes) took 84, 83, and 16 days

respect ve yFabrication of 2400 m long product pipe took 4 months between Feb and

a 07

Product pipe pushing took 6 days to complete in July 07


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Approx. 20,000 m 3 of soil removed during tunneling

Tunnelling activity took days to complete

Total concrete used is 5,700 m 3 and steel used 820 t.

Number of RCC Tunnel pipes used is 616.Annular space filled with grout (mix of fly ash, cement andbentonite); 3,500 t of fl ash, 1,000t of cement and 400 t ofbentonite; Total grout used 8,600 m 3.Grout filling done from East to Central Shaft and Shallow to

en ra a n ays an ays respec ve y


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-


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Background Past history in executing large dia HDD were limited at the project

development stage.

attempted ever before.

Any failure would seriously affect the project completion schedule,.

HDD Contractors willing to stretch the limit of technology, but were

unwilling to take high risks involved. Despite approaching renowned HDD Contractors worldwide, firm

proposals could not be secured.

To encourage HDD Contractors participation, innovative concepts of

Cost Plus and Risk Sharing were required. Infrastructure related works got done separately

equipment selection.


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Constraints River flood-prone during monsoon (July October) and HDD works

were to be performed between November and June.

working space availability.

Entry/exit points were to be located within the river, so that drilled.

Any delay in construction, may result in work abandonment due to

river flooding Space available between exit point and the flood bund not enough for

accommodating the product pipe string

Flood Bunds were not permitted to be cut open, hence requiring huge

temporary ramps to be constructed on either sides Pulling the pipe over the ramp required additional equipment provision


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Crossing Location

Crossing located at KP 64.7 on EWPL Trunkline in Andhra Pradesh State

.

Product pipe : 48 dia, 25.4 mm thk, X-70, & FOC 8 dia

Flood Bund Flood Bund

Pipe Side Rig Side


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Design Site investigation done, soil analysis and scour potential estimated, pipe

profile worked out to be below the scour profile.

ax mum cover o m e ow e r ver e

Due to stiffness of 48, 25.4 mm thk pipe, profile with a radius of 2000 mfor both entry and exit curves required.

Pipe profile passed through successive layers of 200 m of silty sand atentry curve, a second section of 1100 m of clay layer on the central

horizontal section, and in a final section of 424 m of silty sand at the exitcurve

Entry & Exit angle - 6 Deg

oil conditions avorable or HDD but the inter ace between the silt -

sand and clay layers were critical


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Methodology Methodology developed duly taking into account the field constraints

and the risks involved , Para Track system considered of tracking the pilot hole Floatation trench considered to reduce the pipe weight and to reduce

the ull-bac orces Ramps on either sides of flood bund on pipeside considered to enable

pipe cross-over during pull-back operation

Buo anc s stem considered to reduce downhole i e wei ht, and alsonot to exert loading during pull-back on ramp

Multiple contingency arrangements viz. RCC Anchors, Air Hammer andwinches provided for

Round the clock working considered due to the type of soil present HDD Specialists mobilised to provide round the clock support andtechnical assistance


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pe ne ro e

Pi e ProfileScour Profile


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Infrastructural Works

Approach roads from nearest main road to Rig Side and Pipe Side Anchor foundation for 400T/250T Rig Lagoons for mud preparation & water storage

Ramp on Flood bunds for Vehicular movement and string

preparation/Pulling Floatation Trench for Pipe string Anchors for contingency


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Equipment Deployment Drilling Spread comprising of 2 no. rigs viz. 400 T with a torque

capacity of 120 kNm on the rig side, and a 250 T rig with a torquecapacity of 90 kNm on the pipe side.

Downhole tools consisting of 2000 m 5 drill pipes Gr S 135 and 2000m 5 Gr S 135 drill pipes; 10 no. fly cutters and 9 no. barrel reamers ofvarious sizes

Mud equipment included 2 no. mud mixing tank, 2 no. recycling unit, 3no. high pressure pumps (for 2.5 m 3/ minute), 13 no. transfer pumps and

2 no. mud return pumps (150 m3/ minute) for running the mud system inbetween mixing, recycling and pumping equipment. Air Hammer Taurus combined with 2 no. 30 t winches to provide

assistance to 400 T rig at the tail of the product pipe during pull backoperation

600 T THR Bentonite and 50 t additives mobilised with mud engineers

., .


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perations

Mobilization started in September 2006, and the first drilling spread (250

tons) reached the site two months later for starting the first pilot hole Drilling spreads, including one 400 T and 250 T rigs, set up at entry and

exit points, located inside the floodable zone of the river

Product pipe string, 1724 m long, positioned at the exit side, over 5 m highflood bund by building two ramps .

To reduce the pulling loads, entire pipe string beyond flood bund made tofloat within a trench filled with water.

string between the trench and exit point, thru the ramp.


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Exit Side Layout

Rollers over Ramp


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48 String in Floatation Trench


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HDD Operations Work performed on 24 hrs basis due to the nature of soil present 1st Pilot hole completed in 23 days including pull back of casing pipe. 2nd

.5 drill pipe.

For both pilot holes, entry casings 200 meter, 12 diameter, inserted

in position while pushing on the long drill string. Hole opening completed in 52 days with both 400 t and 250 t rig

. Hole opening operation done in five successive reaming passes with

buoyant fly cutters upto a final size of 68.- 32 Fly + 28 Barrel 1st stage- 44 Fly + 40 Barrel 2nd stage- 54 Fly + 50 Barrel 3rd stage- 60 Fly + 56 Barrel 4th stage- 66 Fly + 62 Barrel 5th stage


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HDD Operations During 1st pull back operations, a twist off of the pulling assembly

occurred between swivel joint and pull head, while pulling thru gravelinterface at exit curve.

48 pipe already pulled approx. 500 m inside the reamed hole wasremoved with assistance of Taurus Air Hammer and side booms

nd, ,back attempt performed two weeks later successfully in 72 hrs, andexperiencing a maximum pull force of 320 t.

,by air-hammer oprations.


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Contin enc Arran ement


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Buoyancy System Insertion and Retrieval

HDPE Pipes insertion HDPE Pipes Retrieval

HDD C i i EWPL


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HDD Crossings in EWPL

LIST OF HDD CROSSINGS

Sl.No. Name of the Crossing Chainage(km) LENGTH

1 CORANGI RIVER 1 & 2 9.20 945.0

2 CORANGI CANAL 19.38 328.03 MANDAPETA CANAL 49.46 359.0

+ . .

5 GODAVARI MAIN CANAL 62.75 535.0

6 VASISTA GODAVARI RIVER 64.78 1724.0

7 ENUMUDURU DRAIN+ CANAL 76.68 515.08 ELURU CANAL+NH5 99.96 355.0

9 ELURU CANAL+NH5 125.55 331.0

10 PURNA RIVER 1287.49 670.0

. .

12 NARMADA RIVER 1368.23 1324.0Total Length, m 8236.0


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construction including delayed arrival of rigs, bentoniteblow-out, failure during 1st pull back attempt, damage to

,completed and World Record thus made due todetermination of Team EWPL

work execution and creating History.


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TAPI RIVER CROSSING


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Surat


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EXECUTION

HDD work awarded, equipment mobilised and installation procedure

finalised in time to commence the work.

RoU issues arose at the work site, thus necessitating re-routing resulting

in change in crossing location.

Soil investigation redone and presence of gravel and boulders detected.

,methodologies became necessary

Micro-tunnellin not found feasible within the time available for

implementation Trench excavation by open-cut the trench and pipeline installation by

float & sink technique was only feasible option.4


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EXECUTION Trenching in underwater with water based equipment, excavation in steep

in working out an installation methodology

Also no Contractor was willing to undertake the works with a single point

responsibility.

Specialists engaged separately to detail the installation methodology ,

identify and select the equipments, and make a plan for implementation.

Separate Agencies engaged for

underwater trenching/backfilling & excavation on bank

pipeline installation

5


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D i


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Desi n

Pi eline desi ned in com liance with ASME B31.8 and a licable statutor

regulations.

Pipe wall thickness selected for design and checked for installation

conditions involving pulling of pipeline

Anti-buoyancy measures viz. continuous concrete coating of 130 mm

provided on the pipe

Elastic bending radius of 2000 m adopted

pe ne es gne o ave a m n mum cover o . m rom e r ver e .

7


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Pipe string with swan neck bends on either sides of the straight

section considered, to avoid coffer-dam for tie-in with adjoining

section.-

pulling operations in water

HDD Drill Ri considered for i e ullin instead of conventional drumwinch, as it could be erected within the RoU, could be mobilised

easily, to provide pull force in a controlled manner

To enable the concrete coated pipe to float during pulling, customdesigned floatation tanks considered

Partial pulling followed by mounting of floatation tanks considered

due to interfering State Highway on the north bank


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Special mechanism considered for floatation tank release, for better

control in release and recovery after installation

Hold-back with side-booms and dozers considered to prevent string-

To reduce the pipe pulling loads, concrete coated pipe string

fabricated over custom-made heav dut rollers. 26 T each i e wt. Shoring with sheet piles considered to prevent trench collapse

Combined dead-man anchor and sheet-pile wall considered to take

care of the HDD Rig loads during pulling Trench profile monitoring with echo-sounder and GPS considered

String Fabrication and Pulling


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g g Trench prepared on both banks to suit the profile of the pipeline. (Max

depth > 20 m and width approx. 25 m)

Pipe string o 41 pipes o 492 m engt pre a ricate on pipe ro ers.

Floats mounted on pipes and connected to the steel band tied over the

the pipe to facilitate easy pull-out

After trench clearance, Pi-Derrick mounted on otoons launched, andthe swan neck bend held in position with a chain-pulley block.

HDD Drill pipe with a swivel attached to the pull-head provided at the

bottom of swan neck bend. Pulling of the string carried out with HDD Rig (400 T); 90 T sidebooms

also pushed the pipe during pulling operation, to reduce the pulling

efforts Drill Rig 11


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Trenching Operations


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g p

Excavation near North

Bank

Excavation in River

Excavation near South

Bank


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Back filling


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Back filling

Sand and spoil dredged earlier were again dredged and pumped back in

to the trench over the pipe for cover, using pontoon mounted

excavator and sand boat dredgers.

Wherever the cover found to be less, grout bags with sand and

cement in 1:10 ratio placed over the backfill; transportation by barge

. Positioning done with GPS and monitoring done with bathymetric

surve .

In addition, smaller grout bags with sand cement mix were also spreadover the large grout bags in post-monsoon season.

15


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TERNA RIVER (MAKNISUBMERGENCE) CROSSING

COFFER DAM METHOD


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,

Maharashtra,

depth.

Due to unprecedented rainfall in the year 2007, the extent of

location found to be varying between 6 - 9 m encountered.

18

.


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Extent of submer ence soil strata and accessibilit to site osed

constraints in carrying out HDD.

Inaccessibilit o crossin location necessitated develo in an

installation methodology adopting conventional technique.

Due to di iculties in trenchin /back illin in var in water de th o 6 9 m, bottom pull option ruled out.

Co erdam methodolo even thou h uite voluminous was ound

feasible. Hence adopted for implementation

19

PROJECT PLANNING


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PROJECT PLANNING

Soil required for cofferdam construction was approx. 350,000 cu m

(Approx. 40,000 dumper truckloads)

Dewatering the cofferdam required approx. 10,000 cu m / hr pumping

capacity

To ensure stability, cofferdam size minimized and 4 no. of cofferdamconstructed which eased the pipeline construction

In order to avoid increase in water level during monsoon and

consequent difficulty in constructing cofferdam, works were plannedto be completed within 16 weeks time.

20

PROJECT PLANNING


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Resources identified and mobilised to complete the works within 16

wee s.

Major resources required were dumpers, dewatering pumps, excavatorsan roc rea ers.

To minimise the time for transportation of soil, land in the vicinity of

crossing ease an soi excavate or construction o co er am. is

methodology substantially saved the efforts and in turn time.

Two i erent agencies engage viz.

- Cofferdam construction and dismantling

21

- ewater ng, trenc ng, str ng ng, p pe ne nsta at on an ac ng

COFFERDAM CONSTRUCTION


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Width of Cofferdam at the base kept considering the eventuality ofencountering water level increasing upto 9 m.

cofferdam Dewatering pumps to maintain discharge capacity of 10,000 m3/hr

de lo ed.

Once dewatered, equipment mobilised to cofferdam for trenching and rock-breaking.

Pre-tested pipes strung and welded in trench and equipment movement

within cofferdam minimised.

Due to difficulty in handling heavy concrete coated pipes, option of geo-textiles bag filled with crushed stone (2.2 T/m) adopted for anti-buoyancymeasure.

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Cofferdam Construction Sequence


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Pipeline Installation

Coffer Dam #2 Coffer Dam #3Coffer Dam #1

Coffer Dam #4Su

Su

me

me

rge

rge

ncPipeline Buriednc


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Difficulties Encountered

Difficulties faced including partial collapse of cofferdam, water

seepage, increased water level due to early onset of monsoon, etc.

Despite all the difficulties, the work could be carried out and

completed within the targeted time schedule of 4 months from

December 07 to April 08.

24


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AcknowledgementThanks to Reliance Management for this Presentation and

Reliance Construction Groups for providing valuable inputs in

re ar ng s resen a on


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uestion and Answer


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ewpl - s. jayachandra

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