No Dig Technology Ppts

8/8/2019 No Dig Technology Ppts

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No Dig TechnologyNo Dig Technology


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No-Dig Technology is the art and science of

,pipes, ducts and cables using techniques thatminimizes / eliminates the need for excavation,.e., cons ruc ng un er e sur ace or su sur ace

construction.The term trenchless technolo has been in useon a global basis since the mid-1970s (Japan).The use of such techniques can reduceenvironmental im act social costs and at the

same time provide economic alternatives totraditional open cut methods of installation,

.


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Faster schedules can be achieved since time required for diversion

, .

pipes can carry on regardless of state of traffic at the ground level.Less relocation of utilities is required and risk of damage to utilities

.

Risk of damage to existing structures is reduced as pavements,

roads, trees do not have to be excavated or cut.Surface settlement is minimized resulting in less damage tosurrounding buildings and structures.

No lowering of groundwater table is required.

Existing commercial activities at ground surface can carry onunabated.

Amount of earth moved is reduced leadin to lower dis osal costs.

Reduced risks to workers due to absence of temporary structuresand earth collapse.


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All types of rigid or flexible pipes can be burst/ installed/

repa re , v z:Clay Steel Polymer Ductile Iron Polyethylene Cement

Hobas (Fibre glass) Poly Vinyl Chloride (PVC) High

Density Polyethylene (HDPE)

Gas Lines, Water Lines, Sewer Mains, CommunicationDucts/Cables


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Site investigation to determine soil and

groundwater conditionsInspection to determine the condition of thepipeline

Location survey to determine the position of ex st ng p pe nes, ot er serv ces an potent aobstacles

- e y s e e e y wservices too small to permit man entry, generally

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For providing service it is important that adequate and

eta e s te nvest gat on w t re evant mater a test ngbe carried out and that the information and itsinter retations are made available.


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This survey is carried out when there is doubtconcern ng t e con t on o an ex st ng un ergrounnetwork. It is important to carry out a CCTV survey.


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In No-Dig method the position of the driving tool iscont nuous y mon tore us ng a transm tter n t edriving head and a locater on the surface.


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--Trenchless Technology Systems for

underground utility services fall into three broadcategories:

Installation of a new pipeline or duct;On line replacement of an existing pipeline orduct;

Renovat on Repa r o an ex st ng p pe ne orduct.


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The methods for the installation of a new

pipeline or duct along with service connectionsare:

Micro TunnelingShort Drive SystemsHorizontal Directional Drilling

Guided Drilling


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Controlled Excavation Steerable - less than 1000mm

MTBMs have now been developed to work from drive.

Micro tunneling is used extensively for sewerage work

where surface disruption has to be minimized. Itlines.With the development of micro tunneling, both concrete

.Pipes in all conventional materials are produced with in-wall joints and in shorter lengths to enable smaller driveshafts to be used, thus reducin excavation volumes androad occupancy.


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Schematics courtesy of ISTT


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Essentially Un Steered - Soil Displacement

uger Boring & T rust Boring

Auger Boring utilizes a rotating head to excavate the soil which istransported by auger flights operating in a casing to the drive pit.The head is recovered at an exit pit or in the trench cut for theadjacent length of pipeline. Auger boring is used in the range of 100

- 1000mm diameter.


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Impact Moling

Impact moling is a technique in which a percussive mole (soildisplacement hammer) is launched from an excavation todisplace the soil and form a bore. The new conduit isnormally drawn in behind the mole or pulled back into thebore using the hammers reverse action. Pneumatically driven

moles, in which the soil is displaced by the action of a -,180mm diameter for a single operation, with repetitivemultiple passes to achieve 200 - 250mm diameter.

They are used to install services for all utilities. Moles arecommonly used by gas and water undertakings forinstallations of up to 40m under roads, drives and gardens in

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Pipe Ramming/ Thrust BoringAre processes where a casing, usually steel, is driven through theground from the drive pit to the exit pit. In Pipe Ramming, thecasing is driven by a pneumatic hammer whilst in Thrust Boring itis advanced by a straight hydrau ic push.

Rams of pipes up to and over 2m diameter and exceeding 70m in

length have been achieved.


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Steerable Heavy, powerful rig - large size range - Long distances

This system was origina y deve oped by the oi industry for river

crossings of small diameter where no high degree of accuracy wasrequired. They are now widely used for installing pressure pipes

,and airport runways.


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Steerable Small Rig - Shallow Drilling - Medium

engtGuided drilling employs an excavation with

.Small diameter jets, mechanized cutting tools or

displacement heads attached to a flexible drills r ng are pos one o orm a ore as e ea sthrust forward. The drilling head is launched fromthe surface at an inclined angle. Steering, in bothvertical and horizontal planes, is effected bycontrolling the orientation of a slant face at the

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--Methods of on-line replacement are:

Pipe Eating


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New for Old without Trenching - Size for Size &

In this method old pipes are replaced byfragmenting the pipe of equal or larger diameterp pe.Pipe Bursting, sometimes called Pipe Splitting (usedon non-fragmental pipes such as Steel, Ductile Ironor o yet y ene , an as een eve ope to exp o tthis resource. Initially the aim was for size-for-sizereplacement by splitting the defective pipe and

sp ac ng e ragmen s o ena e a new p pe ne othe same diameter, usually of polyethylene (PE), tobe drawn in.


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It is used for replacement of fractured pipe

usually from excavations 10-200m apart.Upsizing from 100mm to 225mm diameter isnow we es a s e , an p pes o up o mmdiameter and greater have been replaced.


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Two methods are commonly used as outlined:

Static Bursting (Rod or Winch Systems) &Pneumatic Bursting


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New for Old without Trenching - Enlargement -

teera ePipe Eating is an on-line micro tunneled replacement

removed through the new pipeline by the circulating

slurry system. A new pipe is simultaneously installed byac ng e n e m cro unne ng mac ne.


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Renovation methods are:

Lining Formed in Placepray- n n ng

Localized Repair

Chemical Stabilization


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New for Old without Trenching - Long Lengths

It is one of the earliest forms of continuous structurallinin . A new i eline of smaller diameter is insertedinto the defective pipe and the annulus grouted. It issimple and is relatively inexpensive. However, there canbe si nificant loss of h draulic ca acit .

Examples include the pulling in of long lengths of PE

pipes within sewers. This is generally a low costtechnique, which has the disadvantage of reduction of

ore.


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These are methods of lining pipes with a thin lining of res n typ ca y mm t c , w c s spraye onto t esurface of a cleaned main. The aim of these techniquesis to isolate the host i e from the conve ed medium.There may be some potential for these techniques to beused to reinforce the structural capabilities of the host

.


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Corrosion Protection

This is a well tried and tested technique for applyingeither anti-corrosion or structural lining to pipes. A high

centrifugally depositing the lining material over the full

internal surface.


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Resin Injection and Chemical Grouting at

Local defects may be found in an otherwisesound pipeline, due to cracking or joint failure.Systems are available for remote control resininjection to seal localized defects in the range100mm - 600mm diameter.Chemical Grouting with urethane and similarmaterials has been used for many years in sewer

-.of defective joints and cracks may preventinfiltration and the formation of external voids

.


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Restoring Support for SewersThe stability of sewers in doubtful ground conditions may berestored by treating manhole lengths with a two-part chemicaldosing. The sewer length is sealed and filled first with solution Awhich is then pumped out and refi ed with so ution B which is a sosubsequently pumped out. The chemical reaction between the

components seals joints and cracks in the pipe and stabilises the.

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