Advances in Trenchless Technology
Content
ADVANCES IN TRENCHLESS TECHNOLOGY
A TECHNICAL PAPER ON
Submitted By: DARADE DHARMA KACHARU
B.E.(CIVIL)
VIKRAM K. KAMATH
B.E.(CIVIL)
Guided By: Dr. ARUN KUMAR
H.O.D. (Civil Dept.)
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ADVANCES IN TRENCHLESS TECHNOLOGY
CONTENTS CHAPTER PAGE NO.
1] INTRODUCTION …………………………………………………….. 01 2] SCOPE.......................................................................................... 03 3] TECHNIQUES………………………………………………………….04 4] SAFETY MEASURE ……………………………………………………09 5] ADVANTAGES & DISADVANTAGES……………………………….11 6] COMPARATIVE STUDY………………………………………...........12 7] APPLICATION / USES………………………………………………...13 8] INDIAN USE…………………………………………………………….14 9] A CASE STUDY………………………………………………………..15 10] PHOTOGRAPHS………………………………………………………16 CONCLUSION…………………………………………………………18 BIBLIOGRAPHY……………………………………………………… 19
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ADVANCES IN TRENCHLESS TECHNOLOGY
CHAPTER 01
INTRODUCTION the
Definition: - “Trenchless Technology” is an innovative process of installing and
under-ground utilities like water sever and gas pipelines, electricity and communication cables and other underground facilities. This technique minimizes and eliminates the need for excavation of open cut –trenches. Some time it is also referred as ‘No Dig’ method. It is an eco-friendly, hi-tech, speedy construction method for the future builders and the construction industry in India.
History:- “Trenchless Technology” or “No dig Technology” is a comparative of recent
origin i.e. only 15-20 years old. Australia was one of the first countries to use this technology later on Japan, Germany, U.S.A., U.K., etc used this technology. Trenchless Technology has become an effective and economic alternative to traditional open cut construction method’s followed in construction industry, particularly used in the laying and rehabilitation of underground utilities which is mentioned above. In India, this technology was introduced for the first time in Kolkata four year back by Bose international, which is currently acting as technical adviser to Broadway infrastructure. India offers a huge market for trenchless technology. Leading equipment manufacturers from world over are eager to enter India in collaboration with Indian partners. Our metropolitan cities viz.Delhi,Kolkata,Mumbai,Chennai&Bangalore& other fast growing state capitals are congested have outgrown their master- plan limits necessitating immediate need for rehabilitation, renovation, augmentation of existing old water supply and sewer lines and also new installation . Lying of communication cables, gas and oil pipelines and power cables is yet another area for adoption of the trencheles technology which has already gained momentum in a substantial measure. There is some special application too like construction of sub-ways, creating underground space, microhydel power plants, recharging of underground water table, ore slurry transportation, etc. Nowhere in the world where trenchless technology is adopted, have government issued any legislation. Based on the inherent advantages, governments have only facilitated and encouraged the industry to adopt the technology in their countries. The success story
3
ADVANCES IN TRENCHLESS TECHNOLOGY
from Singapore shows how they introduced the technology just by banning digging off open trenches across the road. Potential market:-India is the most populous country in the world next only to china. in spite of the planned economic growth, the urban centers/cities have been growing population continuously migrating from rural areas to urban areas.Delhi,Mumbai,Calcutta,Madras and Bangalore etc.have already reached their limit of congestion,pollution,shortage of water supply, breakdown and blockages in city sewerage systems calling for municipal/public health engineers to undertake immediate measures to provide new or renovate and repair existing utility systems.Goverment of India has also laid stress on immediate development of infrastructure. India is poised offer a huge market for trenchless technology particularly for manufacture of equipment, materials and other geotechinal equipment.It also offers growing employment opportunity for public health engineers, technicians and semi- skilled workers all over India. Currently very few engineers aware of the advantage of trenchless technology in India. As the awareness grows, social costs evaluated the choice will be for trenchless technology from open cut method.
4
ADVANCES IN TRENCHLESS TECHNOLOGY
CHAPTER NO.2
SCOPE
The aid of this article is to briefly discuss about the development and management of the trenchless technology underground utilities infrastructure and to focus attention of administrators,builders,engineers,academicians,consultants.Heads of civicbodies like municipal corporations, water and sewerage Boards ,state electricity boards, Department of telecommunications, cable operators, ministry of surface transport, Ministry of environment, engineering colleges etc.for its early adoption. This article generally introduces and discusses various trenchless technology methods being used for laying new underground utilities and rehabilitation of age old and damaged underground utilities.
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ADVANCES IN TRENCHLESS TECHNOLOGY
CHAPTER NO.3
TECHNIQUES
Techniques can be classified in two broad groups as follows, 1] New installation method 2] Rehabilitation & renovation of existing installations. 3.1 New installations: - New underground utilities like sewers, water supply pipe lines, cables etc. are installed by methods like pipe jacking,Microtunnelling,moling,directional /guided drilling, rod pushing etc.(table1).Equipment and material required is described in the succeeding paragraphs. Associated with these are a number of essential geo-technical services/surveys. 1.Pipe Jacking:-After the construction of jacking pit and the receiving pit, sufficient number of hydraulic jacks were mobilized to site.(The push of the jack being 600 mm, 4 jacks were adopted to work in tandem) Table 2:- New installation methods Services Trenchless methods ●Sewers & water supply ●Pipe jacking – pipelines ●Sewers/water pipelines ●Oil pipelines ●Gas pipelines ●cables ●Microtunnelling & pipe jacking – ●Directional drilling – ●Guided drilling●Impact moling●Rod pushing(>200mm) (50mmto600mm) (<300mm) (<300mm) Diameter (>1000mm) (>250mm)
2. Horizontal Directional Drilling:-It can be defined as drilling done along a predefined profile by a drilling tool and pulling the product pipe along the already drilled hole. It consist two stages: Stage1:- It consists of drilling a small diameter pilot hole along the desired centerline of a Proposed line. Stage2:- Pilot hole is enlarged to the desired diameter to accommodate the utility line & to pull the utility line through the enlarged hole. The pilot hole is of approximately 3inches
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ADVANCES IN TRENCHLESS TECHNOLOGY
(75mm) in diameter &is drilled with a specially built rig up with an inclined carriage, typically adjusted to between 5&30 degrees which pushes the drill rod in to the ground. As the pilot hole is being drilled, bentonite drilling mud is pumped down the center of drill rods. 3. Ramming: - In this method the pipe is rammed through the soil by using a device attached to the end of the pipe to drive the pipe through the soil. In this method, the tool does not create a bore hole. It acts as hammer to drive the pipe through the soil. it sufficient room is available the bore pit is constructed so to enable the pipe to be driven as a single unit in case of congest areas, the pipe is installed in segments of size depending of the bore pits available. The type of pipe installed by the ramming method is limited to steel due to the application of cyclic impact loads on the pipe. The size of pipe installed by this method ranges from 2 inches (50mm) to 55 inches(1400mm). This method is capable off installing pipes to near 200 inches (60m) in length. 4. Auger boring:The auger horizontal earth boring processes of simultaneously jacking casing through the earth while removing the spoil inside the encasement by means of rotating flight auger. The auger is flighted tube having a dual function firstly it has coupling at each end that transmits torque to the cutting head from the power source located in the bore pit & secondly it serves to transfer spoil back to the machine. The casing support the soil around it spoils is being removed. This method requires bore pits both at the entry & exit points of the bore. The size of boring pits depends on the size & length of casing pipe being used. 5. Impact Moling:This method requires the use of boring & receiving pits. The tool is then removed & cable is attached to the air hose & pulled back through the bore hole. When rigid pipe is to be installed the tool & air hose are removed & the pipe is push through the open bore hole. Since the boring process is independent of the pipe insertion process any type of pipe or cable can be installed in the bore hole by this method. Table 3: Trenchless Rehabilitation Methods
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ADVANCES IN TRENCHLESS TECHNOLOGY
Method
Diame ter Range (mm)
100-2700 100-1400
Maximum Installatio n (Meters)
900 150
Linear Materials
Application
CIPP: a) Inserted in place b) Winched in place Slip lining : a) segmental b) continuous c) spiral wound
*Thermoset resin/fabric composite *Thermoset resin/fabric composite
Gravity& pressure pipelines Gravity &pressure pipelines Gravity& pressure pipelines Gravity &pressure pipelines Gravity &pressure pipelines
100-4000 100-1600 100-2500
300 300 300
PE,PP,PVC PVC,PE,PP PE, PVC, PP,PVDF
Inline Replacement : a)Pipe displacement b) Pipe removal Close Fit Pipe : a) Modified cross section b) Draw down c) Roll down Point Source Repair : a) Robotics structural repair Grouting Link-seal Point CIPP Spray-onlining M Manhole Rehabilitation b) c) d) e)
100-600 Up to 900
230 100
PE,PP,PVC PE,PVC,PP
Gravity and pressure pipelines Gravity and pressure pipelines Gravity and pressure pipelines Gravity and pressure pipelines Gravity and pressure pipelines Gravity Any Any Gravity Gravity and pressure pipelines Sewer manholes
100-400 62-600 62-600
210 320 320
HDPE,PVC, HDPE, PVC HDPE,MDPE
270-760 N/A 100-600 100-600 76-4500
N/A N/A N/A 15 150
Epoxy resin/cement mortar Chemical grouting Special sleeve Fibre glass polyester Epoxy resin/cement mortar
Any
N/A
Spray-on-lining, PVC,CIPP 8
ADVANCES IN TRENCHLESS TECHNOLOGY
3.2 HOW TO USE: Rehabilitation & Renovation: - pipeline rehabilitation & renovation is a process of improving the performance & extending the life of existing utility pipelines. The process thus enhances the economic value of the utility pipeline. The improvement of performances &extending the life span can be achieved by enhancing the structural, hydraulic & environmental performance of the utility pipeline by various rehabilitation & renovation methods, described hereinafter. Table-2 gives further highlights of Trenchless methods adopted for rehabilitation & renovation of underground utilities. Cured In Place Pipe (CIPP):- CIPP is liquid thermostat resin-saturated material that is inserted in to the existing pipeline by hydrostatic or air inversion or mechanically pulling with a winch and cable. The material is heat cured in place. (Example: In-situ form, In pipe, In liner, etc.) Slip Lining:-Slip lining is one of the earliest method pipeline rehabilitation. A new pipe of smaller diameter is inserted by pulling or pushing in to deteriorated host pipe. The annular space in between is grouted. This is a simple and inexpensive method but in this method hydraulic capacity is reduced. Different methods in use are: a) Continuous slip lining by HDPE pipes b) Segmental lining by GRP:PVC,PE pipes c) Spirally wound lining ,by helically winding a “T” ribbed plastic liner with interlocking edges,eg.Rib Lock In line replacement: when pipe lines are structurally failing or inadequate, then “inline” replacement should be considered. This is a relatively expensive methods. We can upsize the pipe. Existing pipe line is removed & a new pipe line is installed by pipe bursting. Pipe removal is done by breaking/eating or by pipe displacement method. Close fit pipe:- coiled deformed new pipe installed in the host pipe & expanded to its original size & shape, after placement, to provide a close fit. (Example; Nu pipe, Am-liner, U-liner, Swage lining, roll down pipe etc.) Point source repairs :- when local defects like cracks, joint failure are found, point source repairs are resorted to by remote controlled robotic structural repair, grouting, CIPP,link seal shortcrete & epoxy coatings, spray-on-lining coats are also resorted to.
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ADVANCES IN TRENCHLESS TECHNOLOGY
Sewer manhole rehabilitation: - sewer manhole requires rehabilitation for structural defects, cracks, corroded concrete surface, etc. & to prevent surface water inflow & ground water infiltration. Methods adopted are sealing epoxy, spray-on-lining, cast-in-place, cured –in-place, & profile PVC, etc. Pull Back:-back reaming is done only after the pilot bore is completed. When the sensor is exposed at exit pit, the sensor is removed from the rod and Reamer attached to it, depending on size of the product to be pulled. Method of installation:Expanda process:-This process is specially designed for smaller diameter sewers (150 to 750 mm) and produces liner which closely fits to the existing host pipe. Rib steel process: - This method is used for larger diameter sewers (>900mm).This involves the production of new pipe slightly smaller than the existing host pipe. A winding cage is lowered in to the manhole chamber. Rotaloc Method:-The rotaloc winding machines is lowered to the base of the manhole chamber through standard manhole openings. The PVC profile is fed in to the machine from above ground spool.
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ADVANCES IN TRENCHLESS TECHNOLOGY
CHAPTER NO.4 SAFETY MEASURE Follow these guide lines before operating any jobsite equipment. ● Complete proper training and read operator’s manual before using equipment. ● Mark jobsite clearly and keep spectators away. ● Use equipment carefully. Stop operation and investigate anything that does not look or feel right. ● Do not operate unit where flammable gas is present. ● Wear personal protective equipment. Underground Hazards: Striking underground hazards can cause explosion, electrocution, fire, and exposure to hazardous materials. Hazards include: ●Electric lines ●Natural gas lines. ●Fibre optic cables. ●Water lines. ●Sewer lines. ●Pipes carrying other chemicals, liquids, or gases ●Storage tanks Electric Strike Description When working near electric cables, remember the following: ●Electricity follows all paths to ground, not just path of least resistance. ●Pipes, hoses, and cables will conduct electricity back to all equipment. ●Low voltage current can injure or kill. Almost one-third of work related electrocution result from contact with less than 440 volts. Most electric strikes are not noticeable, but indication of a strike includes: ●Power outage
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ADVANCES IN TRENCHLESS TECHNOLOGY
●Smoke ●Explosion ●Popping noises ●Arcing electricity If any of these occur, or if strike alarm sound or flashes, assume an electric strike has occurred. If an Electric Lane is damaged On Drilling Unit or Bonded Ground Mats: 1) DO NOT MOVE. Remain on drilling machine or mats. 2) Warn people nearby that an electric strike has occurred 3) Have someone contact electric company. 4) Reverse drilling direction and try to break contact. Do not touch drill pipe with hands Or hand-held tools. 5) Press electric strike system status button. *If alarm sounds again, stay where you are and wait for electric company to shut off power. *If alarm does not sound and there is no other indication of a strike, wait at least one full minute before moving away from equipment. Utility might use automatic reclosers which will restart current flow. If a Gas line is damaged ● Immediately shut off engines(S) & remove any ignition sources. ● LEAVE AREA as quickly as possible. ● Warn others that a gas line has been cut and that they should leave area. ● Contact emergency personnel. ● Do not return to area until given permission by utility company. If a fiber optic line is damaged Do not look in to cut ends of fiber optic or unidentified cable.
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ADVANCES IN TRENCHLESS TECHNOLOGY
CHAPTER NO.5
5.1 ADVANTAGES OF ADOPTING TRENCHLESS TECHNOLOGY
(a) Quality in construction (b) Economy (c) Speedy construction (d) Skill up-gradation (e) Accident free (f) Reduces noise pollution (g) Avoids traffic jam (h) Saves resources (i) Reduces damages of valuable surface (j) It makes the use of the line (track) of the old pipe possible (pipe bursting). (k) It reduces the impact on tree and flowers. (l) It reduces the danger of improperly compacted excavation. (m) It avoids annoyance of the residents. (n) It saves under ground space. (o) It reduces impact on the environment after cleaning the old pipe
5.2 DISADVANTAGES • • • • • High initial cost of equipment. Skilled or trained person is required for handling the equipment. In case of availability of huge labour force on cheaper rate going for this method will be uneconomical especially in villages and small town etc. Maintance cost and operation cost is more. Spare parts of equipments are not available easily in market.
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ADVANCES IN TRENCHLESS TECHNOLOGY
CHAPTER NO.6 APPLICATION/ USES The following fields of application are crered by trenchless technology Gas pipeline Oil pipelines Water pipelines Sewer pipelines Electric/power lines& cables Data communication cables Telecommunication cables 1) This method is very useful to lay utility lines below Airport Runway. 2) Trenchless technology is use where conventional method is impossible i.e. laid utility lines below the 2m or more below the ground surface. 3) This method is very useful when the utility pipes lay under a Rail track or road where conventional method is impossible. 4) This method is very useful when the utility pipes lay under a Riverbed or canal where conventional method is impossible.
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ADVANCES IN TRENCHLESS TECHNOLOGY
CHAPTER NO.7 COMPARATIVE STUDY OPEN CUT METHOD 1)Traffic hindrance: TRENCHLESS TECHNOLOGY Traffic 1) Such disadvantages should be
obstruction,accidents,extra cost in providing eliminated by adopting this technology. diversions and their maintenance etc. 2)Environmental pollution: Dust & air 2) Eliminated. pollution by vehicle & machines, noise pollution,pollution of ground & Surface water 3)Commerce POL 4) Citizen & Society: Increased avoidable cost in repair & rehabilitation the roads, compensative for damages, advantage of early availability of the utility & avoidance 5) Imperative. of public hindrance etc. 5) Not imperative. and industry: Loss of sale,productivity,increase 3) Eliminated. consumption 4) Eliminated.
CHAPTER NO.8
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ADVANCES IN TRENCHLESS TECHNOLOGY
INDIAN USE OF TRENCHLESS TECHNOLOGY 1) City trunck main constructed with pipe jacking technique across national highways. (NH4 & NH7) 2) Over 5km of microtunnelling was completed between March 2000 & July 2002 in the suburbs of Mumbai, for Bombay Municipal Council (BMC). The initial works comprising 800 mm & 1000 mm diameter pipelines were carried out by microtunnelling as an expedient to overcome environmental disturbances that would be brought about by cut & cover construction in the highly congested urban areas. Such was the success of the project that the original range of pipe size was increased to include 1250mm pipes & the scope of the works was extended within the life of the project. 3) MTNL & Calcutta telephones have already opted for utilization of no-dig technology for laying cables.MTNL has awarded a contract for laying 185km of telephone cables using this technology. 4) Now a day Reliance Company laid cable by using this method only. 5) Laying of 18 inches diameter feeder pipeline of HBJ (Hazira-Jagdishpur) across Yamuna River near Indraprastha gas turbine power station in Delhi. 6) Oil & gas Commission laid to 28 m long &42 inches diameter pipeline across river Tapi 7) Gas Authority of India Ltd, using this technology, laid 18 inches diameter gas line across river Gautami-Godavari35 m below lowest riverbed level. This crossing is 1719m long and the longest in the world. 8) Jamnagar/Kandala-Loni LPG pipeline will originate at Jamnagar & terminate at Loni .The pipeline runs through Gujarat (522Kms) Rajasthan (630 Km.), Haryana (75 Km.) & Delhi (5 Km.).
CHAPTER NO.9
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ADVANCES IN TRENCHLESS TECHNOLOGY
A CASE STUDY The company motto is ‘Do not dig; we drill for your comfort’! The project: The work of laying twin HT cable from VIDHANA SOUDHA Bangalore to its new annex building was entrusted to KEPL at a cost of Rs. 2.25 lakhs. Works was restricted to be carried out only on Saturday & Sunday. Details of work as follows: Client : PWD- Vidhana Soudha Contractors: Krita Engg. Pvt. Ltd. Bangalore Site Location: Vidhana Soudha Road towards K.R. Circle Strata : Murram & at certain points rock & boulders After back reaming Hole Dia. Cost Duration : 250mm : Rs.2.24 lakhs (@Rs 1000/-per meter) : 2 day (Saturday & Sunday) & 7 days for planning, survey & mobilisation. Before the work was taken in hand initial planning ,survey and mobilization took 7 days for firm; actual instillation having taken 2 days only. Preliminary planning included following activities: * Survey * Selection of route / layout * GPR survey * Selection of equipment * Safety & security * Traffic control Survey: a) Preliminary physical survey b) GPR survey c) Geotech consideration Pipe length : 225mtrs (2*240sq mm cable plus one 14 core control cable)
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ADVANCES IN TRENCHLESS TECHNOLOGY
CHAPTER NO.10 PHOTOGRAPHS
JEA High Volume Pipe Bursting
Ohio River HDD Crossing
King County, Wash., Pipe Burst
Pipe Ram Assists During HDD Pullback
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ADVANCES IN TRENCHLESS TECHNOLOGY
West Roxbury tunnel
Tampa Bypass Canal Horizontal Pile Driving
What is the biggest problem you
Temperature restrictions for HDPE
Temperature restrictions for HDPE
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ADVANCES IN TRENCHLESS TECHNOLOGY
CONCLUSIONS Within a short span of 5-6 years, the awareness of trenchless technology in India is quite significant. With progressive adoption of trenchless technology in India, new equipment and development of new materials will follow which will revolutionize the construction industry and benefit the society. However, many planners, designers and engineers are not yet accustomed to using them. Hence, there is a need for further technological refinement, better information dissemination, and greater public awareness and understanding regarding appropriate use of trenchless technology and its contribution to environmentally sustainable urban development. It is hoped that seminars on this newer technology will be encouraged which will promote greater awareness in adoption of this new technology for the development and management of underground utilities.
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ADVANCES IN TRENCHLESS TECHNOLOGY
BIBLIOGRAPHY: Websites: 1. http://www.istt.com/net 2. http://ce.ecn.purdue.edu/cem/trench/piperamming.html 3. http://www.estt.org 4. http://www.nastt.org Journals: 5. Journal of “Indian Society for Trenchless Technology”. 6. Trenchless Technology-Social cost by R.K.Sharma, NBCC Ltd. 7. Civil Engineering and Construction Review (May 2002). 8. Civil Engineering and Construction Review (April 2004). 9. ‘Underground utility infrastructure’ literature held at ‘Bangalore’ 10. “Trenchless Technology- The India scene” by Dr.V.M.Sharma, Advance Technology and Engineering services (AIMIL).
21
A TECHNICAL PAPER ON
Submitted By: DARADE DHARMA KACHARU
B.E.(CIVIL)
VIKRAM K. KAMATH
B.E.(CIVIL)
Guided By: Dr. ARUN KUMAR
H.O.D. (Civil Dept.)
1
ADVANCES IN TRENCHLESS TECHNOLOGY
CONTENTS CHAPTER PAGE NO.
1] INTRODUCTION …………………………………………………….. 01 2] SCOPE.......................................................................................... 03 3] TECHNIQUES………………………………………………………….04 4] SAFETY MEASURE ……………………………………………………09 5] ADVANTAGES & DISADVANTAGES……………………………….11 6] COMPARATIVE STUDY………………………………………...........12 7] APPLICATION / USES………………………………………………...13 8] INDIAN USE…………………………………………………………….14 9] A CASE STUDY………………………………………………………..15 10] PHOTOGRAPHS………………………………………………………16 CONCLUSION…………………………………………………………18 BIBLIOGRAPHY……………………………………………………… 19
2
ADVANCES IN TRENCHLESS TECHNOLOGY
CHAPTER 01
INTRODUCTION the
Definition: - “Trenchless Technology” is an innovative process of installing and
under-ground utilities like water sever and gas pipelines, electricity and communication cables and other underground facilities. This technique minimizes and eliminates the need for excavation of open cut –trenches. Some time it is also referred as ‘No Dig’ method. It is an eco-friendly, hi-tech, speedy construction method for the future builders and the construction industry in India.
History:- “Trenchless Technology” or “No dig Technology” is a comparative of recent
origin i.e. only 15-20 years old. Australia was one of the first countries to use this technology later on Japan, Germany, U.S.A., U.K., etc used this technology. Trenchless Technology has become an effective and economic alternative to traditional open cut construction method’s followed in construction industry, particularly used in the laying and rehabilitation of underground utilities which is mentioned above. In India, this technology was introduced for the first time in Kolkata four year back by Bose international, which is currently acting as technical adviser to Broadway infrastructure. India offers a huge market for trenchless technology. Leading equipment manufacturers from world over are eager to enter India in collaboration with Indian partners. Our metropolitan cities viz.Delhi,Kolkata,Mumbai,Chennai&Bangalore& other fast growing state capitals are congested have outgrown their master- plan limits necessitating immediate need for rehabilitation, renovation, augmentation of existing old water supply and sewer lines and also new installation . Lying of communication cables, gas and oil pipelines and power cables is yet another area for adoption of the trencheles technology which has already gained momentum in a substantial measure. There is some special application too like construction of sub-ways, creating underground space, microhydel power plants, recharging of underground water table, ore slurry transportation, etc. Nowhere in the world where trenchless technology is adopted, have government issued any legislation. Based on the inherent advantages, governments have only facilitated and encouraged the industry to adopt the technology in their countries. The success story
3
ADVANCES IN TRENCHLESS TECHNOLOGY
from Singapore shows how they introduced the technology just by banning digging off open trenches across the road. Potential market:-India is the most populous country in the world next only to china. in spite of the planned economic growth, the urban centers/cities have been growing population continuously migrating from rural areas to urban areas.Delhi,Mumbai,Calcutta,Madras and Bangalore etc.have already reached their limit of congestion,pollution,shortage of water supply, breakdown and blockages in city sewerage systems calling for municipal/public health engineers to undertake immediate measures to provide new or renovate and repair existing utility systems.Goverment of India has also laid stress on immediate development of infrastructure. India is poised offer a huge market for trenchless technology particularly for manufacture of equipment, materials and other geotechinal equipment.It also offers growing employment opportunity for public health engineers, technicians and semi- skilled workers all over India. Currently very few engineers aware of the advantage of trenchless technology in India. As the awareness grows, social costs evaluated the choice will be for trenchless technology from open cut method.
4
ADVANCES IN TRENCHLESS TECHNOLOGY
CHAPTER NO.2
SCOPE
The aid of this article is to briefly discuss about the development and management of the trenchless technology underground utilities infrastructure and to focus attention of administrators,builders,engineers,academicians,consultants.Heads of civicbodies like municipal corporations, water and sewerage Boards ,state electricity boards, Department of telecommunications, cable operators, ministry of surface transport, Ministry of environment, engineering colleges etc.for its early adoption. This article generally introduces and discusses various trenchless technology methods being used for laying new underground utilities and rehabilitation of age old and damaged underground utilities.
5
ADVANCES IN TRENCHLESS TECHNOLOGY
CHAPTER NO.3
TECHNIQUES
Techniques can be classified in two broad groups as follows, 1] New installation method 2] Rehabilitation & renovation of existing installations. 3.1 New installations: - New underground utilities like sewers, water supply pipe lines, cables etc. are installed by methods like pipe jacking,Microtunnelling,moling,directional /guided drilling, rod pushing etc.(table1).Equipment and material required is described in the succeeding paragraphs. Associated with these are a number of essential geo-technical services/surveys. 1.Pipe Jacking:-After the construction of jacking pit and the receiving pit, sufficient number of hydraulic jacks were mobilized to site.(The push of the jack being 600 mm, 4 jacks were adopted to work in tandem) Table 2:- New installation methods Services Trenchless methods ●Sewers & water supply ●Pipe jacking – pipelines ●Sewers/water pipelines ●Oil pipelines ●Gas pipelines ●cables ●Microtunnelling & pipe jacking – ●Directional drilling – ●Guided drilling●Impact moling●Rod pushing(>200mm) (50mmto600mm) (<300mm) (<300mm) Diameter (>1000mm) (>250mm)
2. Horizontal Directional Drilling:-It can be defined as drilling done along a predefined profile by a drilling tool and pulling the product pipe along the already drilled hole. It consist two stages: Stage1:- It consists of drilling a small diameter pilot hole along the desired centerline of a Proposed line. Stage2:- Pilot hole is enlarged to the desired diameter to accommodate the utility line & to pull the utility line through the enlarged hole. The pilot hole is of approximately 3inches
6
ADVANCES IN TRENCHLESS TECHNOLOGY
(75mm) in diameter &is drilled with a specially built rig up with an inclined carriage, typically adjusted to between 5&30 degrees which pushes the drill rod in to the ground. As the pilot hole is being drilled, bentonite drilling mud is pumped down the center of drill rods. 3. Ramming: - In this method the pipe is rammed through the soil by using a device attached to the end of the pipe to drive the pipe through the soil. In this method, the tool does not create a bore hole. It acts as hammer to drive the pipe through the soil. it sufficient room is available the bore pit is constructed so to enable the pipe to be driven as a single unit in case of congest areas, the pipe is installed in segments of size depending of the bore pits available. The type of pipe installed by the ramming method is limited to steel due to the application of cyclic impact loads on the pipe. The size of pipe installed by this method ranges from 2 inches (50mm) to 55 inches(1400mm). This method is capable off installing pipes to near 200 inches (60m) in length. 4. Auger boring:The auger horizontal earth boring processes of simultaneously jacking casing through the earth while removing the spoil inside the encasement by means of rotating flight auger. The auger is flighted tube having a dual function firstly it has coupling at each end that transmits torque to the cutting head from the power source located in the bore pit & secondly it serves to transfer spoil back to the machine. The casing support the soil around it spoils is being removed. This method requires bore pits both at the entry & exit points of the bore. The size of boring pits depends on the size & length of casing pipe being used. 5. Impact Moling:This method requires the use of boring & receiving pits. The tool is then removed & cable is attached to the air hose & pulled back through the bore hole. When rigid pipe is to be installed the tool & air hose are removed & the pipe is push through the open bore hole. Since the boring process is independent of the pipe insertion process any type of pipe or cable can be installed in the bore hole by this method. Table 3: Trenchless Rehabilitation Methods
7
ADVANCES IN TRENCHLESS TECHNOLOGY
Method
Diame ter Range (mm)
100-2700 100-1400
Maximum Installatio n (Meters)
900 150
Linear Materials
Application
CIPP: a) Inserted in place b) Winched in place Slip lining : a) segmental b) continuous c) spiral wound
*Thermoset resin/fabric composite *Thermoset resin/fabric composite
Gravity& pressure pipelines Gravity &pressure pipelines Gravity& pressure pipelines Gravity &pressure pipelines Gravity &pressure pipelines
100-4000 100-1600 100-2500
300 300 300
PE,PP,PVC PVC,PE,PP PE, PVC, PP,PVDF
Inline Replacement : a)Pipe displacement b) Pipe removal Close Fit Pipe : a) Modified cross section b) Draw down c) Roll down Point Source Repair : a) Robotics structural repair Grouting Link-seal Point CIPP Spray-onlining M Manhole Rehabilitation b) c) d) e)
100-600 Up to 900
230 100
PE,PP,PVC PE,PVC,PP
Gravity and pressure pipelines Gravity and pressure pipelines Gravity and pressure pipelines Gravity and pressure pipelines Gravity and pressure pipelines Gravity Any Any Gravity Gravity and pressure pipelines Sewer manholes
100-400 62-600 62-600
210 320 320
HDPE,PVC, HDPE, PVC HDPE,MDPE
270-760 N/A 100-600 100-600 76-4500
N/A N/A N/A 15 150
Epoxy resin/cement mortar Chemical grouting Special sleeve Fibre glass polyester Epoxy resin/cement mortar
Any
N/A
Spray-on-lining, PVC,CIPP 8
ADVANCES IN TRENCHLESS TECHNOLOGY
3.2 HOW TO USE: Rehabilitation & Renovation: - pipeline rehabilitation & renovation is a process of improving the performance & extending the life of existing utility pipelines. The process thus enhances the economic value of the utility pipeline. The improvement of performances &extending the life span can be achieved by enhancing the structural, hydraulic & environmental performance of the utility pipeline by various rehabilitation & renovation methods, described hereinafter. Table-2 gives further highlights of Trenchless methods adopted for rehabilitation & renovation of underground utilities. Cured In Place Pipe (CIPP):- CIPP is liquid thermostat resin-saturated material that is inserted in to the existing pipeline by hydrostatic or air inversion or mechanically pulling with a winch and cable. The material is heat cured in place. (Example: In-situ form, In pipe, In liner, etc.) Slip Lining:-Slip lining is one of the earliest method pipeline rehabilitation. A new pipe of smaller diameter is inserted by pulling or pushing in to deteriorated host pipe. The annular space in between is grouted. This is a simple and inexpensive method but in this method hydraulic capacity is reduced. Different methods in use are: a) Continuous slip lining by HDPE pipes b) Segmental lining by GRP:PVC,PE pipes c) Spirally wound lining ,by helically winding a “T” ribbed plastic liner with interlocking edges,eg.Rib Lock In line replacement: when pipe lines are structurally failing or inadequate, then “inline” replacement should be considered. This is a relatively expensive methods. We can upsize the pipe. Existing pipe line is removed & a new pipe line is installed by pipe bursting. Pipe removal is done by breaking/eating or by pipe displacement method. Close fit pipe:- coiled deformed new pipe installed in the host pipe & expanded to its original size & shape, after placement, to provide a close fit. (Example; Nu pipe, Am-liner, U-liner, Swage lining, roll down pipe etc.) Point source repairs :- when local defects like cracks, joint failure are found, point source repairs are resorted to by remote controlled robotic structural repair, grouting, CIPP,link seal shortcrete & epoxy coatings, spray-on-lining coats are also resorted to.
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Sewer manhole rehabilitation: - sewer manhole requires rehabilitation for structural defects, cracks, corroded concrete surface, etc. & to prevent surface water inflow & ground water infiltration. Methods adopted are sealing epoxy, spray-on-lining, cast-in-place, cured –in-place, & profile PVC, etc. Pull Back:-back reaming is done only after the pilot bore is completed. When the sensor is exposed at exit pit, the sensor is removed from the rod and Reamer attached to it, depending on size of the product to be pulled. Method of installation:Expanda process:-This process is specially designed for smaller diameter sewers (150 to 750 mm) and produces liner which closely fits to the existing host pipe. Rib steel process: - This method is used for larger diameter sewers (>900mm).This involves the production of new pipe slightly smaller than the existing host pipe. A winding cage is lowered in to the manhole chamber. Rotaloc Method:-The rotaloc winding machines is lowered to the base of the manhole chamber through standard manhole openings. The PVC profile is fed in to the machine from above ground spool.
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CHAPTER NO.4 SAFETY MEASURE Follow these guide lines before operating any jobsite equipment. ● Complete proper training and read operator’s manual before using equipment. ● Mark jobsite clearly and keep spectators away. ● Use equipment carefully. Stop operation and investigate anything that does not look or feel right. ● Do not operate unit where flammable gas is present. ● Wear personal protective equipment. Underground Hazards: Striking underground hazards can cause explosion, electrocution, fire, and exposure to hazardous materials. Hazards include: ●Electric lines ●Natural gas lines. ●Fibre optic cables. ●Water lines. ●Sewer lines. ●Pipes carrying other chemicals, liquids, or gases ●Storage tanks Electric Strike Description When working near electric cables, remember the following: ●Electricity follows all paths to ground, not just path of least resistance. ●Pipes, hoses, and cables will conduct electricity back to all equipment. ●Low voltage current can injure or kill. Almost one-third of work related electrocution result from contact with less than 440 volts. Most electric strikes are not noticeable, but indication of a strike includes: ●Power outage
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ADVANCES IN TRENCHLESS TECHNOLOGY
●Smoke ●Explosion ●Popping noises ●Arcing electricity If any of these occur, or if strike alarm sound or flashes, assume an electric strike has occurred. If an Electric Lane is damaged On Drilling Unit or Bonded Ground Mats: 1) DO NOT MOVE. Remain on drilling machine or mats. 2) Warn people nearby that an electric strike has occurred 3) Have someone contact electric company. 4) Reverse drilling direction and try to break contact. Do not touch drill pipe with hands Or hand-held tools. 5) Press electric strike system status button. *If alarm sounds again, stay where you are and wait for electric company to shut off power. *If alarm does not sound and there is no other indication of a strike, wait at least one full minute before moving away from equipment. Utility might use automatic reclosers which will restart current flow. If a Gas line is damaged ● Immediately shut off engines(S) & remove any ignition sources. ● LEAVE AREA as quickly as possible. ● Warn others that a gas line has been cut and that they should leave area. ● Contact emergency personnel. ● Do not return to area until given permission by utility company. If a fiber optic line is damaged Do not look in to cut ends of fiber optic or unidentified cable.
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CHAPTER NO.5
5.1 ADVANTAGES OF ADOPTING TRENCHLESS TECHNOLOGY
(a) Quality in construction (b) Economy (c) Speedy construction (d) Skill up-gradation (e) Accident free (f) Reduces noise pollution (g) Avoids traffic jam (h) Saves resources (i) Reduces damages of valuable surface (j) It makes the use of the line (track) of the old pipe possible (pipe bursting). (k) It reduces the impact on tree and flowers. (l) It reduces the danger of improperly compacted excavation. (m) It avoids annoyance of the residents. (n) It saves under ground space. (o) It reduces impact on the environment after cleaning the old pipe
5.2 DISADVANTAGES • • • • • High initial cost of equipment. Skilled or trained person is required for handling the equipment. In case of availability of huge labour force on cheaper rate going for this method will be uneconomical especially in villages and small town etc. Maintance cost and operation cost is more. Spare parts of equipments are not available easily in market.
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CHAPTER NO.6 APPLICATION/ USES The following fields of application are crered by trenchless technology Gas pipeline Oil pipelines Water pipelines Sewer pipelines Electric/power lines& cables Data communication cables Telecommunication cables 1) This method is very useful to lay utility lines below Airport Runway. 2) Trenchless technology is use where conventional method is impossible i.e. laid utility lines below the 2m or more below the ground surface. 3) This method is very useful when the utility pipes lay under a Rail track or road where conventional method is impossible. 4) This method is very useful when the utility pipes lay under a Riverbed or canal where conventional method is impossible.
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CHAPTER NO.7 COMPARATIVE STUDY OPEN CUT METHOD 1)Traffic hindrance: TRENCHLESS TECHNOLOGY Traffic 1) Such disadvantages should be
obstruction,accidents,extra cost in providing eliminated by adopting this technology. diversions and their maintenance etc. 2)Environmental pollution: Dust & air 2) Eliminated. pollution by vehicle & machines, noise pollution,pollution of ground & Surface water 3)Commerce POL 4) Citizen & Society: Increased avoidable cost in repair & rehabilitation the roads, compensative for damages, advantage of early availability of the utility & avoidance 5) Imperative. of public hindrance etc. 5) Not imperative. and industry: Loss of sale,productivity,increase 3) Eliminated. consumption 4) Eliminated.
CHAPTER NO.8
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INDIAN USE OF TRENCHLESS TECHNOLOGY 1) City trunck main constructed with pipe jacking technique across national highways. (NH4 & NH7) 2) Over 5km of microtunnelling was completed between March 2000 & July 2002 in the suburbs of Mumbai, for Bombay Municipal Council (BMC). The initial works comprising 800 mm & 1000 mm diameter pipelines were carried out by microtunnelling as an expedient to overcome environmental disturbances that would be brought about by cut & cover construction in the highly congested urban areas. Such was the success of the project that the original range of pipe size was increased to include 1250mm pipes & the scope of the works was extended within the life of the project. 3) MTNL & Calcutta telephones have already opted for utilization of no-dig technology for laying cables.MTNL has awarded a contract for laying 185km of telephone cables using this technology. 4) Now a day Reliance Company laid cable by using this method only. 5) Laying of 18 inches diameter feeder pipeline of HBJ (Hazira-Jagdishpur) across Yamuna River near Indraprastha gas turbine power station in Delhi. 6) Oil & gas Commission laid to 28 m long &42 inches diameter pipeline across river Tapi 7) Gas Authority of India Ltd, using this technology, laid 18 inches diameter gas line across river Gautami-Godavari35 m below lowest riverbed level. This crossing is 1719m long and the longest in the world. 8) Jamnagar/Kandala-Loni LPG pipeline will originate at Jamnagar & terminate at Loni .The pipeline runs through Gujarat (522Kms) Rajasthan (630 Km.), Haryana (75 Km.) & Delhi (5 Km.).
CHAPTER NO.9
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A CASE STUDY The company motto is ‘Do not dig; we drill for your comfort’! The project: The work of laying twin HT cable from VIDHANA SOUDHA Bangalore to its new annex building was entrusted to KEPL at a cost of Rs. 2.25 lakhs. Works was restricted to be carried out only on Saturday & Sunday. Details of work as follows: Client : PWD- Vidhana Soudha Contractors: Krita Engg. Pvt. Ltd. Bangalore Site Location: Vidhana Soudha Road towards K.R. Circle Strata : Murram & at certain points rock & boulders After back reaming Hole Dia. Cost Duration : 250mm : Rs.2.24 lakhs (@Rs 1000/-per meter) : 2 day (Saturday & Sunday) & 7 days for planning, survey & mobilisation. Before the work was taken in hand initial planning ,survey and mobilization took 7 days for firm; actual instillation having taken 2 days only. Preliminary planning included following activities: * Survey * Selection of route / layout * GPR survey * Selection of equipment * Safety & security * Traffic control Survey: a) Preliminary physical survey b) GPR survey c) Geotech consideration Pipe length : 225mtrs (2*240sq mm cable plus one 14 core control cable)
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CHAPTER NO.10 PHOTOGRAPHS
JEA High Volume Pipe Bursting
Ohio River HDD Crossing
King County, Wash., Pipe Burst
Pipe Ram Assists During HDD Pullback
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West Roxbury tunnel
Tampa Bypass Canal Horizontal Pile Driving
What is the biggest problem you
Temperature restrictions for HDPE
Temperature restrictions for HDPE
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CONCLUSIONS Within a short span of 5-6 years, the awareness of trenchless technology in India is quite significant. With progressive adoption of trenchless technology in India, new equipment and development of new materials will follow which will revolutionize the construction industry and benefit the society. However, many planners, designers and engineers are not yet accustomed to using them. Hence, there is a need for further technological refinement, better information dissemination, and greater public awareness and understanding regarding appropriate use of trenchless technology and its contribution to environmentally sustainable urban development. It is hoped that seminars on this newer technology will be encouraged which will promote greater awareness in adoption of this new technology for the development and management of underground utilities.
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BIBLIOGRAPHY: Websites: 1. http://www.istt.com/net 2. http://ce.ecn.purdue.edu/cem/trench/piperamming.html 3. http://www.estt.org 4. http://www.nastt.org Journals: 5. Journal of “Indian Society for Trenchless Technology”. 6. Trenchless Technology-Social cost by R.K.Sharma, NBCC Ltd. 7. Civil Engineering and Construction Review (May 2002). 8. Civil Engineering and Construction Review (April 2004). 9. ‘Underground utility infrastructure’ literature held at ‘Bangalore’ 10. “Trenchless Technology- The India scene” by Dr.V.M.Sharma, Advance Technology and Engineering services (AIMIL).
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