Trenchless Technology: Pipe Rerounding, Auger Boring, Intelligent Pigging, Epoxy Resin, Micro Tunnelling, Pipe Ramming, Pneumatic Hammer, No Dig, Mud Pump Flow Rate, Bentonite, Corporate Membership and Sliplining
Society for Trenchless Technology
The UKSTT (United Kingdom Society for Trenchless Technology) is a registered charity involved in the development and promotion of trenchless techniques, sometimes termed no dig techniques. TRENCHLESS TECHNOLOGY: UTILITY WORKS, UNDERGROUND PIPELINES, TRENCHLESS TECHNIQUES, SEWERS Our society should be of interest to all people involved in the installation of new and renewal or replacement of, pipes, sewers or cables. It should also be of special interest to government bodies, environmentalists, or anyone with concern over street works or traffic congestion. In detail this site offers the chance for the UKSTT membership to update on the societies activities, but also, more importantly, gives those involved in utility works, construction, etc. a window to view and learn about the equipment and materials involved in trenchless techniques, activities and, if required, source specialist consultants, suppliers and contractors to carry out such works. Trenchless technology is increasingly accepted worldwide as being more efficient, less disruptive, environmentally friendly and more cost effective than traditional methods. Information on the Techniques can be viewed in the technologies section of our website, with suppliers and contractors details shown within the membership directory. For those new to trenchless technology, a glossary is also available to give greater understanding. UKSTT was formed in 1993 and incorporated the existing UK based members of ISTT. The international society, ISTT, was formed in 1986 but since that time has promoted the formation of National Societies in many different countries. The formation of these national societies helped to give the local members a sense of identity and autonomy to pursue their own ideas. UKSTT is structured as a company limited by guarantee where its elected council members act as directors and guarantors. UKSTT set out its aims and objectives in much the same way as the international society but with more emphasis on the exchange and networking of information and ideas throughout the UK utility industry. UKSTT operates as a company and a society where council members are elected on a yearly basis, and financial accounts are kept and presented to the membership at an AGM each year. The Council meets six to eight times per year to discuss the issues raised through the secretariat and the various council members. Our aims and objectives include: to advance the science and practice of the trenchless technology for the public benefit to promote education, training, study and research in the science and practice to encourage the use of trenchless systems for the installation and repair of underground pipelines, utilities and services to promote the location and mapping of underground services to encourage the development of new trenchless techniques to assist members to maintain and enhance their knowledge, skills and capabilities in the field of trenchless technology INDIVIDUAL & CORPORATE MEMBERSHIP: CABLE OPERATORS, CONTRACTORS, PIPELINE INDUSTRIES GUILD, CIVIL ENGINEERS, UTILITY COMPANIES, NO DIG Utility companies, cable operators, local authorities, contractors, suppliers, consultants, academics, research organisations - in fact, any company or individual with an interest in modern systems of utility installation and repair will benefit from membership of UKSTT. Trenchless Technology is being increasingly accepted worldwide as being more efficient, less disruptive and more cost effective than traditional methods. UKSTT offers you the opportunity to participate in the 'no dig revolution' and keep up to date with the latest advances. Corporate & Individual Membership (all members) benefits include: latest information on new technologies and developments access to a network of contacts including clients, consultants, contractors, suppliers and academic institutions regular regional, national and international technical meetings free subscription to no dig international magazine opportunity to attend regular joint meetings with other relevant organisations such as the institution of civil engineers and the pipeline industries guild regular newsletter opportunity to attend the UKSTT annual awards dinner being part of ISTT with its worldwide contacts through 24 other affiliated societies membership certificate Additional Benefits of Corporate Membership free business opportunities as a result of redirected enquiries to UKSTT secretariat free company details on, and links from, the UKSTT web site opportunity to sponsor major events i.e. awards dinner, newsletter opportunity to present papers at UKSTT conferences and UKSTT sponsored events opportunity to present papers at no-dig live - the world's largest live no dig event opportunity to present papers at UKSTT technical evenings opportunity to take part in technical showcase workshops opportunity to become involved in the development of trenchless technologies in the construction industry involvement in the promotion of trenchless technology with the UK government participate in trenchless technology training initiatives and research opportunity to take part in international exhibitions using grant aid sponsored by SESA. use of UKSTT logo on company stationary and publicity material reduced exhibition cost at sponsored exhibitions i.e. IWEX, no dig live. opportunity to display company literature at international no dig exhibitions at a nominal cost free editorials in UKSTT newsletter reduced costs at conferences, exhibitions and training seminars relating to trenchless technology recognition by clients of your company's involvement in technological advance the opportunity to be involved in an important growth area of business opportunity to bring guests to the UKSTT annual awards dinner access to various national and international award schemes free entry on the UKSTT members' activity database. TRAINING PROGRAMMES: HYDRAULIC PIPE BURSTING SYSTEMS, FLUID ASSISTED HORIZONTAL DIRECTIONAL DRILLING, IMPACT MOLE OPERATOR TRAINING UKSTT recognises some training programmes which lead to certification. Our training programmes are provided by TT UK Ltd and are approved by City & Guilds Module 5831Unit 103, 104 and 114. They include: impact mole operator training and assessment courses fluid assisted horizontal directional drilling equipment course hydraulic pipe bursting systems operator training and assessment courses
The UKSTT (United Kingdom Society for Trenchless Technology) is a registered charity involved in the development and promotion of trenchless techniques, sometimes termed no dig techniques.
Our society should be of interest to all people involved in the installation of new and renewal or replacement of, pipes, sewers or cables. It should also be of special interest to government bodies, environmentalists, or anyone with concern over street works or traffic congestion. In detail this site offers the chance for the UKSTT membership to update on the societies activities, but also, more importantly, gives those involved in utility works, construction, etc. a window to view and learn about the equipment and materials involved in trenchless techniques, activities and, if required, source specialist consultants, suppliers and contractors to carry out such works. Trenchless technology is increasingly accepted worldwide as being more efficient, less disruptive, environmentally friendly and more cost effective than traditional methods. Information on the Techniques can be viewed in the technologies section of our website, with suppliers and contractors details shown within the membership directory. For those new to trenchless technology, a glossary is also available to give greater understanding.
UKSTT was formed in 1993 and incorporated the existing UK based members of ISTT. The international society, ISTT, was formed in 1986 but since that time has promoted the formation of National Societies in many different countries. The formation of these national societies helped to give the local members a sense of identity and autonomy to pursue their own ideas. UKSTT is structured as a company limited by guarantee where its elected council members act as directors and guarantors. UKSTT set out its aims and objectives in much the same way as the international society but with more emphasis on the exchange and networking of information and ideas throughout the UK utility industry. UKSTT operates as a company and a society where council members are elected on a yearly basis, and financial accounts are kept and presented to the membership at an AGM each year. The Council meets six to eight times per year to discuss the issues raised through the secretariat and the various council members.
Our aims and objectives include:
Utility companies, cable operators, local authorities, contractors, suppliers, consultants, academics, research organisations - in fact, any company or individual with an interest in modern systems of utility installation and repair will benefit from membership of UKSTT. Trenchless Technology is being increasingly accepted worldwide as being more efficient, less disruptive and more cost effective than traditional methods. UKSTT offers you the opportunity to participate in the 'no dig revolution' and keep up to date with the latest advances.
Corporate & Individual Membership (all members) benefits include:
Additional Benefits of Corporate Membership
UKSTT recognises some training programmes which lead to certification. Our training programmes are provided by TT UK Ltd and are approved by City & Guilds Module 5831Unit 103, 104 and 114. They include:
Trenchless Installation, Repair & Renewal
Trenchless Technology is the science of installing, repairing or renewing underground pipes, ducts and cables using techniques that minimises or eliminates the need for excavation. The use of such techniques can reduce environmental impact, social costs and at the same time provide economic alternatives to traditional open cut methods of installation, renewal or repair. TRENCHLESS TECHNIQUES: PIGGING, POWER WINCHING, AIR SCOURING, RACK FEED BORING, HIGH PRESSURE WATER JETTING Essential to the success of such methods are training, planning, material and equipment choice. Trenchless techniques themselves can be broken down into three areas: repair and renovation replacement new installation Repair and renovation method includes: cleaning, localised repair techniques and lining techniques. The cleaning method includes: high pressure water jetting, specialist cutting equipment, power winching, drag scraping, pigging, air scouring and rack feed boring. LOCALISED REPAIR TECHNIQUES: STABILISATION TECHNIQUES, CIPP PATCH REPAIR, CHEMICAL STABILISATION, STRUCTURAL PIPE REROUNDING, REPAIR SYSTEMS Repair systems are used to address localised service problems or structural defects within a pipeline. The methods of localised repairs can be grouped as stabilisation or structural repair systems. The following sections describe a number of repair systems using trenchless technologies. In general, a stabilisation technique will address a localised problem, such as infiltration, without adding to the structural integrity of the pipeline. Typically, stabilisation techniques include chemical stabilisation, joint sealing and resin injection although in some circumstances the latter can also be classed as a structural repair. By definition, a defect addressed by a structural repair method will improve the structural integrity of a pipeline. Typical structural repair techniques include CIPP patch repair, robotic repairs and pipe re rounding. Localised repair techniques include: chemical stabilisation, joint sealing & testing, resin injection systems, patch repair systems, robotic repair systems, rerounding and lateral cutting. Localised repair techniques include: CHEMICAL STABILISATION: SEWER REPAIR SYSTEM, FILL AND DRAIN TECHNIQUES, DRAINAGE SYSTEMS, SODIUM SILICATE Renovation of a pipeline and ancillary features by sealing, between two access points by the chemical reaction of added compounds to the surrounding ground. The sealing of drainage systems can be achieved by chemical stabilisation 'fill and drain' techniques, which treat the main sewer, branches and manholes in one operation. Originating in Hungary, the system has been developed and is used quite widely as a 'non-destructive' sewer repair system. The section to be sealed is isolated and then filled from a manhole with an environmentally safe chemical solution (usually sodium silicate). After a predetermined interval to allow the chemical to permeate through leaking joints and cracks, the solution is pumped out quickly. The section is then filled with a second proprietary chemical solution, which reacts with the residue of the first chemical to form a waterproof membrane. The second chemical is then pumped out and the pipe is cleaned to remove any residues. The chemical reaction between the two solutions turns the material surrounding manholes and pipes into an impermeable mass, almost a weak concrete, around points of leakage. Due to the scale of plant requirements and the volumes of materials needed, these systems are more economical for large-scale leakage control projects than the treatment of isolated lengths. The greatest advantage of the method is to treat leaks throughout the whole system in a single operation. JOINT SEALING & TESTING: POLYURETHANE RESIN GROUT The testing and sealing of defective pipe joints with a grout injection using a packer, all activities being from a single process. A common method of sealing leaking joints in gravity pipelines is to use a packer, which combines the functions of leak testing and grout injection. Joint testing and sealing may or may not be 'localised', depending on how many joints fail. A packer with inflatable end elements is positioned across a pipe joint and pressurised to isolate the joint. Air or water pressure is then applied to the centre section of the packer and the rate of pressure loss through the joint is measured. If the loss exceeds a specified limit, a sealing resin compound is injected into the joint through the packer and the joint is re-tested. The packer design varies, using either a two-part acrylic grout or a water-active polyurethane resin grout. The grout combines with the ground around the leaking joint to form an impermeable mass, preventing leaks and enhancing structural stability. Polyurethane resin grouts are hydrophobic and react either with free water in the soil or with a water solution injected through the packer at the same time as the grout. Generally, a ratio of 1 part grout to 8 parts water is recommended for pipe sealing, variations creating products of different strengths.
Trenchless Technology is the science of installing, repairing or renewing underground pipes, ducts and cables using techniques that minimises or eliminates the need for excavation. The use of such techniques can reduce environmental impact, social costs and at the same time provide economic alternatives to traditional open cut methods of installation, renewal or repair.
Essential to the success of such methods are training, planning, material and equipment choice. Trenchless techniques themselves can be broken down into three areas:
Repair and renovation method includes: cleaning, localised repair techniques and lining techniques. The cleaning method includes: high pressure water jetting, specialist cutting equipment, power winching, drag scraping, pigging, air scouring and rack feed boring.
Repair systems are used to address localised service problems or structural defects within a pipeline. The methods of localised repairs can be grouped as stabilisation or structural repair systems. The following sections describe a number of repair systems using trenchless technologies. In general, a stabilisation technique will address a localised problem, such as infiltration, without adding to the structural integrity of the pipeline. Typically, stabilisation techniques include chemical stabilisation, joint sealing and resin injection although in some circumstances the latter can also be classed as a structural repair. By definition, a defect addressed by a structural repair method will improve the structural integrity of a pipeline. Typical structural repair techniques include CIPP patch repair, robotic repairs and pipe re rounding. Localised repair techniques include: chemical stabilisation, joint sealing & testing, resin injection systems, patch repair systems, robotic repair systems, rerounding and lateral cutting. Localised repair techniques include:
Renovation of a pipeline and ancillary features by sealing, between two access points by the chemical reaction of added compounds to the surrounding ground. The sealing of drainage systems can be achieved by chemical stabilisation 'fill and drain' techniques, which treat the main sewer, branches and manholes in one operation. Originating in Hungary, the system has been developed and is used quite widely as a 'non-destructive' sewer repair system. The section to be sealed is isolated and then filled from a manhole with an environmentally safe chemical solution (usually sodium silicate). After a predetermined interval to allow the chemical to permeate through leaking joints and cracks, the solution is pumped out quickly. The section is then filled with a second proprietary chemical solution, which reacts with the residue of the first chemical to form a waterproof membrane. The second chemical is then pumped out and the pipe is cleaned to remove any residues. The chemical reaction between the two solutions turns the material surrounding manholes and pipes into an impermeable mass, almost a weak concrete, around points of leakage. Due to the scale of plant requirements and the volumes of materials needed, these systems are more economical for large-scale leakage control projects than the treatment of isolated lengths. The greatest advantage of the method is to treat leaks throughout the whole system in a single operation.
The testing and sealing of defective pipe joints with a grout injection using a packer, all activities being from a single process. A common method of sealing leaking joints in gravity pipelines is to use a packer, which combines the functions of leak testing and grout injection. Joint testing and sealing may or may not be 'localised', depending on how many joints fail. A packer with inflatable end elements is positioned across a pipe joint and pressurised to isolate the joint. Air or water pressure is then applied to the centre section of the packer and the rate of pressure loss through the joint is measured. If the loss exceeds a specified limit, a sealing resin compound is injected into the joint through the packer and the joint is re-tested. The packer design varies, using either a two-part acrylic grout or a water-active polyurethane resin grout. The grout combines with the ground around the leaking joint to form an impermeable mass, preventing leaks and enhancing structural stability. Polyurethane resin grouts are hydrophobic and react either with free water in the soil or with a water solution injected through the packer at the same time as the grout. Generally, a ratio of 1 part grout to 8 parts water is recommended for pipe sealing, variations creating products of different strengths.
Localised Repair Techniques
Resin injection systems involve the localised repair of pipes by resin injection into defects, the subsequent curing to prevent leakage and further deterioration. RESIN INJECTION SYSTEMS: INFLATABLE PACKER, GROUNDWATER, EXFILTRATION, EPOXY RESIN Resin injection systems, normally using an epoxy resin or mortar, are used to stabilise and re-bond the existing pipe structure, in addition to sealing against exfiltration and /or infiltration. The technique may be considered for more serious defects, such as holes and circular fractures and is usually considered when infiltration / exfiltration problems have been identified. However, care must be taken in areas of high groundwater levels particularly if water runs along the line of the pipeline thus removing the epoxy resin from the area of repair. An inflatable packer is winched into position so that it is centred on the defect. The isolated defect is repaired by the injection of a rapid-setting epoxy resin into the crack, fracture or hole in the pipe wall. The inflatable packer is left in position until the resin has cured and is then deflated and removed. A thin internal collar of resin usually remains after the packer has been withdrawn. Recent developments include the ability to produce an even, thicker lining to provide some stiffness thus approaching a structural repair. Although the technology does not provide a full structural repair it will stabilise a structure by preventing the creation or enlargement of voids in the pipe surround or by reinstating the ground support. Overlapping multiple repairs can achieve a longer repair length. PATCH REPAIR SYSTEMS: THERMAL CURE, THERMAL CURE SYSTEMS, INFLATABLE PACKER, SEWER, AMBIENT CURE SYSTEMS, POLYESTER RESIN Localised pipe repair by positioning a short sleeve of resin-impregnated material within the host pipe and cured. Patch repair systems involve impregnating a fabric with a suitable resin and positioned in place within the sewer around an inflatable packer. The packer filled with water, steam or air under pressure, presses the patch against the existing sewer wall while the resin cures. Both thermal cure systems and ambient cure systems are available. Resins are usually polyester resin (ambient temperatures) or epoxy resin (thermal cure). Patch repairs are short versions of cured-in-place liners, using polyester needle-felt on its own or in combination with glass fibre. Safe working practices are essential particularly when impregnation of the fabric is carried out on site since the spillage of chemicals and good ventilation is needed as polyester resins give off styrene. For both systems, it is necessary to limit the rise in temperature of the materials until the patch is inflated within the pipe and avoid premature cure, which can cause failure. The curing time depends on the resin formulation, the thickness of the patch, the temperature within the packer (in thermal cure systems) and the temperature of the existing pipe wall. A high ground-water table will cool the outer surface of the patch and additional curing time should be allowed for hot cured systems. Ambient cured patches may not have sufficient thermo energy to ensure a full cure. After curing, the packer is deflated and removed. The patch should then be inspected by CCTV, any lateral connections being re-opened using the same techniques available for full length liners. ROBOTIC REPAIR SYSTEMS: GRAVITY PIPELINES, CCTV, EPOXY MORTAR, ROBOTIC REPAIR SYSTEMS, EPOXY RESIN A remote control device with CCTV monitoring is used for the localised repair of defects and obstructions using grinding and filling tools. Robotic repair systems for gravity pipelines comprise of grinding robots and filler robots. Grinding robots remove encrustation and intrusions and also mills out cracks to provide a good surface and key for the repair materials. The filler robot applies an epoxy mortar into the slot formed by the grinder and trowels off the material to a smooth finish. Smaller robots will operate in diameters up to 200 to 400 mm; larger robots in diameters from 300 mm to 800 mm. The hydraulically driven grinding head can be fitted with various shapes of cutter to cope with most pipe materials. Cutters are usually cooled by a water spray issuing from the central hub, providing a coolant and lubricant for the operation. Intruding laterals, grout deposits and hard encrustation can also be removed. The operation of the self-propelled robots is monitored by a CCTV camera attached to the head. The two-part epoxy mortar may be mixed prior to filling the canister on board the filler robot. In some designs, the components are loaded into the robot separately and mixed at the outlet as they are used. The epoxy, applied by a system of remotely controlled nozzles and spatulas is injected through a flexible plate or former pressed against the pipe wall. Defective lateral connections can be repaired by sealing the connections to the main pipe with epoxy resin to form a flush finish. REROUNDING: HYDRAULIC MOLE, DEFORMED PIPE, HYDRAULIC RAMS The insertion of an expansion device into a deformed pipe to return it to a circular shape prior to a permanent repair usually with a lining technique. Rerounding is not a stand-alone technique but is intended to re-shape a deformed pipe prior to patch repair or relining. An expander unit is used to re-round the pipe and install a metal or plastic clip, which holds the pipe fragments in position until a patch or liner is installed. Deformed pipes between magnitudes of 10% to 35% is typical for this type of temporary repair. The expander system is inflated with hydraulic pressure or, alternatively, a hydraulic mole forces steel 'petals' outwards by hydraulic rams. The plastic or metal clip is scrolled around the expander and secured prior to. After positioning under CCTV control, the clip is expanded with sufficient pressure to re-round the pipe. Care must be taken with severely damaged pipes since the unit will take the path of least resistance when expanding.
Resin injection systems involve the localised repair of pipes by resin injection into defects, the subsequent curing to prevent leakage and further deterioration.
Resin injection systems, normally using an epoxy resin or mortar, are used to stabilise and re-bond the existing pipe structure, in addition to sealing against exfiltration and /or infiltration. The technique may be considered for more serious defects, such as holes and circular fractures and is usually considered when infiltration / exfiltration problems have been identified. However, care must be taken in areas of high groundwater levels particularly if water runs along the line of the pipeline thus removing the epoxy resin from the area of repair. An inflatable packer is winched into position so that it is centred on the defect. The isolated defect is repaired by the injection of a rapid-setting epoxy resin into the crack, fracture or hole in the pipe wall. The inflatable packer is left in position until the resin has cured and is then deflated and removed. A thin internal collar of resin usually remains after the packer has been withdrawn. Recent developments include the ability to produce an even, thicker lining to provide some stiffness thus approaching a structural repair. Although the technology does not provide a full structural repair it will stabilise a structure by preventing the creation or enlargement of voids in the pipe surround or by reinstating the ground support. Overlapping multiple repairs can achieve a longer repair length.
Localised pipe repair by positioning a short sleeve of resin-impregnated material within the host pipe and cured. Patch repair systems involve impregnating a fabric with a suitable resin and positioned in place within the sewer around an inflatable packer. The packer filled with water, steam or air under pressure, presses the patch against the existing sewer wall while the resin cures. Both thermal cure systems and ambient cure systems are available. Resins are usually polyester resin (ambient temperatures) or epoxy resin (thermal cure). Patch repairs are short versions of cured-in-place liners, using polyester needle-felt on its own or in combination with glass fibre. Safe working practices are essential particularly when impregnation of the fabric is carried out on site since the spillage of chemicals and good ventilation is needed as polyester resins give off styrene. For both systems, it is necessary to limit the rise in temperature of the materials until the patch is inflated within the pipe and avoid premature cure, which can cause failure. The curing time depends on the resin formulation, the thickness of the patch, the temperature within the packer (in thermal cure systems) and the temperature of the existing pipe wall. A high ground-water table will cool the outer surface of the patch and additional curing time should be allowed for hot cured systems. Ambient cured patches may not have sufficient thermo energy to ensure a full cure. After curing, the packer is deflated and removed. The patch should then be inspected by CCTV, any lateral connections being re-opened using the same techniques available for full length liners.
A remote control device with CCTV monitoring is used for the localised repair of defects and obstructions using grinding and filling tools. Robotic repair systems for gravity pipelines comprise of grinding robots and filler robots. Grinding robots remove encrustation and intrusions and also mills out cracks to provide a good surface and key for the repair materials. The filler robot applies an epoxy mortar into the slot formed by the grinder and trowels off the material to a smooth finish. Smaller robots will operate in diameters up to 200 to 400 mm; larger robots in diameters from 300 mm to 800 mm. The hydraulically driven grinding head can be fitted with various shapes of cutter to cope with most pipe materials. Cutters are usually cooled by a water spray issuing from the central hub, providing a coolant and lubricant for the operation. Intruding laterals, grout deposits and hard encrustation can also be removed. The operation of the self-propelled robots is monitored by a CCTV camera attached to the head. The two-part epoxy mortar may be mixed prior to filling the canister on board the filler robot. In some designs, the components are loaded into the robot separately and mixed at the outlet as they are used. The epoxy, applied by a system of remotely controlled nozzles and spatulas is injected through a flexible plate or former pressed against the pipe wall. Defective lateral connections can be repaired by sealing the connections to the main pipe with epoxy resin to form a flush finish.
The insertion of an expansion device into a deformed pipe to return it to a circular shape prior to a permanent repair usually with a lining technique. Rerounding is not a stand-alone technique but is intended to re-shape a deformed pipe prior to patch repair or relining. An expander unit is used to re-round the pipe and install a metal or plastic clip, which holds the pipe fragments in position until a patch or liner is installed. Deformed pipes between magnitudes of 10% to 35% is typical for this type of temporary repair. The expander system is inflated with hydraulic pressure or, alternatively, a hydraulic mole forces steel 'petals' outwards by hydraulic rams. The plastic or metal clip is scrolled around the expander and secured prior to. After positioning under CCTV control, the clip is expanded with sufficient pressure to re-round the pipe. Care must be taken with severely damaged pipes since the unit will take the path of least resistance when expanding.
Trenchless Lining Techniques
Lining techniques involve various systems including: cement mortar lining systems, epoxy spray lining systems, cure in place pipe lining, sliplining, swage & die draw lining, deformed pipe lining, spirally wound lining, live insertion and service pipe renovation methods. Cement Mortar Lining Systems Cement mortar lining is the application of a cement mortar (typically about 4mm thick) to the inside of pipelines to protect against corrosion. Epoxy Spray Lining Systems These are methods of lining pipes with a thin lining of resin (typically 1mm thick), which are sprayed onto the surface of a cleaned main. The aim of these techniques is to isolate the host pipe from the conveyed medium. There may be some potential for these techniques to be used to reinforce the structural capabilities of the host main. Cure In Place Pipe Lining Method of lining with a flexible tube impregnated with a thermosetting resin, which produces a pipe after resin cure. The lining may be set by the use of heat or UV light. Widely used in sewer applications less used in drinking water applications. Sliplining Techniques by which continuous or discreet pipes are inserted within existing pipes: examples include the pulling in of long lengths of PE pipes within water mains or the insertion of individual pipes within sewers. This is generally a low cost technique, which has the disadvantage of reduction of bore. Swage & Die Draw Lining Close-fit thermoplastic pipe lining systems, which are achieved by stretching a liner pipe by pulling it through one or more dies, to produce a temporary reduction in its diameter. This enables the liner pipe to enter the host pipe and then expand to give a tight fit against the inside of the host. Rolldown Close-fit thermoplastic pipe lining systems, which are achieved by pushing a liner pipe by pulling it through one or more sets of rollers, to produce a temporary reduction in its diameter. This enables the liner pipe to enter the host pipe. It is then expanded to give a tight fit against the inside of the host. Deformed Pipe Lining Compact Pipe- In this system PE pipe is factory extruded in a "C" shape and coiled onto a drum. This shape creates a clearance for the installation of the PE pipe into the host pipe. The folded pipe is then pressurized with steam, which rounds the liner, to form a close fit within the host pipe, sealing leakage and preventing corrosion. The system is designed for distribution and small trunk mains. Subline- The Subline system involves the folding of thin walled polyethylene (PE) into a U shape to enable it to be installed within an existing pipe. The shape is held by a series of bands. This creates a clearance for the installation of the PE pipe into the host pipe, which is to be renovated. The folded pipe is then pressurized. This snaps the bands allowing the liner to revert back to its original shape, to form a close fit within the host pipe, sealing leakage and preventing corrosion. The system is designed for trunk mains. Subcoil- In the Subcoil system PE pipe is factory folded into a "U" shape, which is held by a continuous sleeve. The product is then coiled onto a drum. The folding creates a reduction in diameter, which gives clearance for the installation of the liner into the host. The folded pipe is then cold pressurized which snaps the sleeve allowing the liner to revert back to its original shape, to form a close fit within the host pipe, sealing leakage and preventing corrosion. The system is designed for the renovation of distribution and small trunk mains. Thermopipe- Thermopipe is a circular woven, high tensile polyester reinforced, polyethylene lining system. It is ideally suited for the renovation of water distribution mains and other pressurized piping systems. Supplied as a factory folded 'C' shaped liner, Thermopipe is semi-rigid when cool. Once pulled into the pipe, inflated and heated it becomes flexible and expands. This enables it to achieve a close fit to the host pipe, providing structural lining. Spirally Wound Lining In this system a plastic strip is spirally or helically wound to form a continuous lining. This is held in place initially by the expansion of the helix. A grout layer may be injected between the liner and the host pipe wall. The system is typically used in sewers. Live Insertion Live Insertion is a method of sliplining a cast iron pipe with new PE whilst maintaining gas supplies to consumers. The old cast iron pipe is kept live during the insertion process. Once insertion is complete, the old main is again kept live to supply customers via the annular space. When operationally convenient, services can be transferred to the new PE which has also been 'gassed up'. Whilst primarily used on low pressure mains, the technique can also be used where the PE is tied into a new medium pressure system.
Lining techniques involve various systems including: cement mortar lining systems, epoxy spray lining systems, cure in place pipe lining, sliplining, swage & die draw lining, deformed pipe lining, spirally wound lining, live insertion and service pipe renovation methods.
Cement mortar lining is the application of a cement mortar (typically about 4mm thick) to the inside of pipelines to protect against corrosion.
These are methods of lining pipes with a thin lining of resin (typically 1mm thick), which are sprayed onto the surface of a cleaned main. The aim of these techniques is to isolate the host pipe from the conveyed medium. There may be some potential for these techniques to be used to reinforce the structural capabilities of the host main.
Method of lining with a flexible tube impregnated with a thermosetting resin, which produces a pipe after resin cure. The lining may be set by the use of heat or UV light. Widely used in sewer applications less used in drinking water applications.
Techniques by which continuous or discreet pipes are inserted within existing pipes: examples include the pulling in of long lengths of PE pipes within water mains or the insertion of individual pipes within sewers. This is generally a low cost technique, which has the disadvantage of reduction of bore.
Close-fit thermoplastic pipe lining systems, which are achieved by stretching a liner pipe by pulling it through one or more dies, to produce a temporary reduction in its diameter. This enables the liner pipe to enter the host pipe and then expand to give a tight fit against the inside of the host.
Close-fit thermoplastic pipe lining systems, which are achieved by pushing a liner pipe by pulling it through one or more sets of rollers, to produce a temporary reduction in its diameter. This enables the liner pipe to enter the host pipe. It is then expanded to give a tight fit against the inside of the host.
In this system a plastic strip is spirally or helically wound to form a continuous lining. This is held in place initially by the expansion of the helix. A grout layer may be injected between the liner and the host pipe wall. The system is typically used in sewers.
Live Insertion is a method of sliplining a cast iron pipe with new PE whilst maintaining gas supplies to consumers. The old cast iron pipe is kept live during the insertion process. Once insertion is complete, the old main is again kept live to supply customers via the annular space. When operationally convenient, services can be transferred to the new PE which has also been 'gassed up'. Whilst primarily used on low pressure mains, the technique can also be used where the PE is tied into a new medium pressure system.
Trenchless Replacement Techniques
Replacement techniques of existing utility lines including gas pipes, ducts, water pipes, sewers and potentially cables take place through methods including: pipebursting, pipe splitting, pipe eating and lead extraction and lead replacement systems. PIPEBURSTING: STATIC BURSTING, MANHOLE, HYDRAULIC BURSTER, EXPANDIT PIPE BURSTING, SILT TRENCHES, FRACTURABLE PIPE Pipe Bursting is a method of online replacement of fracturable pipe usually from excavations 10-200m apart. Extensive proving work by the gas and water industries has demonstrated the feasibility of upsizing gas mains, water mains and sewers. An expanding device which, may be either pneumatic or hydraulic, is introduced into the defective pipeline, shattering the pipe and drawing in the new line behind it. Insertion of short lengths may be made from pits but this involves jointing of the pipeline within the pit. This can be avoided by the use of silt trenches to insert pipe strings. Three methods are commonly used as outlined below. Static Bursting (Rod Or Winch Systems)- the pipe to be replaced is exposed and cut out at two points, typically 100 - 120 metres apart in gas/water/ducting applications and 5 - 50 metres in man hole entry applications. The hydraulic burster is positioned in the excavation and the rods individually connected and pushed into the old pipe. Each rod is unscrewed and removed, or in the case of two-way bursting, fed directly into the next 100 metres of pipe, on reaching the hydraulic burster the tooling is disconnected from the new pipe and removed Pneumatic- the pipe to be replaced is exposed and cut out at two points, typically anything from 5 - 100 metres apart. a winch cable is pulled into the old pipe with a cobra flexible rod. using the cobra flexible rodding, the air supply hoses are pulled through the new pipe to be installed and connected to the compressor and the rear of the cracker. The new pipe is secured to the rear of the cracker, which is in turn connected to the winch cable and drawn into the launch pit and the air supply turned on. Expandit Pipe Bursting- The expandit system is a true manhole-to-manhole method of pipe bursting, with no need for excavations. The 2 manholes are prepared for bursting by the removal of the benching and the two pipe entry points. The expandit head is lowered into the launch manhole, whilst a winch is positioned above the reception manhole. The head is then hydraulically expanded & contracted, which bursts the existing pipe, pushing the fragments into the existing pipe bed/surround. The head is then jacked forward using segmental pipe, which is machined to suit the size of the manholes, as jacking progresses, the winch is used to maintain straight-line stability of the head, and to ensure it stays central within the existing pipe. Pipe Splitting Pipe splitting is similar in technique to pipe bursting but is used on non-fragmental pipes such as steel, ductile iron or polyethylene. The technique is generally the same but instead of utilising conical burst head and blade formats the systems use specialist splitting heads designed to cut through the pipe wall, and joints, and expand the existing pipe into the surrounding ground. Pipe Eating Predominantly used on concrete sewer installations this system allows for size for size replacement and upsizing. Pipe eating is an on-line microtunnelled replacement technique. The existing defective pipeline is crushed (or eaten), by the tunnelling machine and removed through the new pipeline. Lateral connections must be disconnected in advance and may be replaced by rider sewers or reconnected by angled drilling. Lead Extraction & Replacement Systems Various systems of extraction are used to predominantly replace lead and steel service pipes. Techniques are varied with impact moles and pipe pulling machines - which utilise clamping jaws to extract the existing steel or lead (which have previously inserted with a steel cable) pipes. All of the systems rely on good strength of the existing material and for the service line to be relatively straight. Pipe & cables installation techniques include: impact moling, pipe ramming, auger boring & thrust boring, pipe jacking, micro tunnelling, guided rod pushing, guided boring & directional drilling, rock boring, cable pulling and cable blow in systems Impact Moling Impact moling is a technique in which a percussive mole (soil displacement hammer) is launched from an excavation to displace the soil and form a bore. The new conduit is normally drawn in behind the mole or pulled back into the bore using the hammers reverse action. Pneumatically driven moles, in which the soil is displaced by the action of a percussive piston, have been developed in the range 30 - 180mm diameter for a single operation, with repetitive multiple passes to achieve 200 - 250mm diameter. Pipe Ramming Pipe ramming is a simple technique utilising a pneumatic hammer to drive steel casings through the ground from one pit to another. Rams of pipes up to and over 2m diameter and exceeding 70m in length have been achieved. During the basic operation, the correct size of rammer is chosen by assessing casing diameter, length of ram and the prevailing ground conditions, positioned on the tracing or 'H' Beam in the launch pit, the rammer and first casing length are connected directly or via ram cones, using adjustable cradles or air-bags, the assembly is aligned and levelled on target, the air supply is partly applied to start the rammer and slowly increased as the first casing enters the ground. Full power is applied when the skin friction on the casing is sufficient to overcome the back stroke of the piston, as each casing length is entered the rammer is removed, the next casing welded in place and the rammer replaced and restarted, on completion of the ram, the soil in the casing can be removed by one of several methods including: pressurisation and blow-out, pressure jetting, mini excavator or by any combination.
Replacement techniques of existing utility lines including gas pipes, ducts, water pipes, sewers and potentially cables take place through methods including: pipebursting, pipe splitting, pipe eating and lead extraction and lead replacement systems.
Pipe Bursting is a method of online replacement of fracturable pipe usually from excavations 10-200m apart. Extensive proving work by the gas and water industries has demonstrated the feasibility of upsizing gas mains, water mains and sewers. An expanding device which, may be either pneumatic or hydraulic, is introduced into the defective pipeline, shattering the pipe and drawing in the new line behind it. Insertion of short lengths may be made from pits but this involves jointing of the pipeline within the pit. This can be avoided by the use of silt trenches to insert pipe strings. Three methods are commonly used as outlined below.
Pipe splitting is similar in technique to pipe bursting but is used on non-fragmental pipes such as steel, ductile iron or polyethylene. The technique is generally the same but instead of utilising conical burst head and blade formats the systems use specialist splitting heads designed to cut through the pipe wall, and joints, and expand the existing pipe into the surrounding ground.
Predominantly used on concrete sewer installations this system allows for size for size replacement and upsizing. Pipe eating is an on-line microtunnelled replacement technique. The existing defective pipeline is crushed (or eaten), by the tunnelling machine and removed through the new pipeline. Lateral connections must be disconnected in advance and may be replaced by rider sewers or reconnected by angled drilling.
Various systems of extraction are used to predominantly replace lead and steel service pipes. Techniques are varied with impact moles and pipe pulling machines - which utilise clamping jaws to extract the existing steel or lead (which have previously inserted with a steel cable) pipes. All of the systems rely on good strength of the existing material and for the service line to be relatively straight.
Pipe & cables installation techniques include: impact moling, pipe ramming, auger boring & thrust boring, pipe jacking, micro tunnelling, guided rod pushing, guided boring & directional drilling, rock boring, cable pulling and cable blow in systems
Impact moling is a technique in which a percussive mole (soil displacement hammer) is launched from an excavation to displace the soil and form a bore. The new conduit is normally drawn in behind the mole or pulled back into the bore using the hammers reverse action. Pneumatically driven moles, in which the soil is displaced by the action of a percussive piston, have been developed in the range 30 - 180mm diameter for a single operation, with repetitive multiple passes to achieve 200 - 250mm diameter.
Pipe ramming is a simple technique utilising a pneumatic hammer to drive steel casings through the ground from one pit to another. Rams of pipes up to and over 2m diameter and exceeding 70m in length have been achieved. During the basic operation, the correct size of rammer is chosen by assessing casing diameter, length of ram and the prevailing ground conditions, positioned on the tracing or 'H' Beam in the launch pit, the rammer and first casing length are connected directly or via ram cones, using adjustable cradles or air-bags, the assembly is aligned and levelled on target, the air supply is partly applied to start the rammer and slowly increased as the first casing enters the ground. Full power is applied when the skin friction on the casing is sufficient to overcome the back stroke of the piston, as each casing length is entered the rammer is removed, the next casing welded in place and the rammer replaced and restarted, on completion of the ram, the soil in the casing can be removed by one of several methods including: pressurisation and blow-out, pressure jetting, mini excavator or by any combination.
Pipe & Cables Installation Techniques
The use of pipe & cables installation techniques can reduce environmental impact, social costs and at the same time provide economic alternatives to traditional open cut methods. Pipe & cables installation techniques include: Micro Tunnelling Micro tunnelling is used here as a general term to describe remotely controlled mechanical tunnelling systems where the spoil is removed from the cutting head within the new pipeline which is advanced by pipe jacking. Micro tunnelling machines have now been developed to work from drive shafts in almost all types of ground conditions. The cutting head has to be carefully selected to deal with the expected ground conditions, with the appropriate cutting tools and crushing devices for the range of gravels, sands, silts, and clays. Water or bentonite may be used to convert the soil into slurry at the cutting face. The slurry is then pumped to the surface where the solids are separated before disposal. Both systems provide face support by mechanical earth pressure balance. Slurry pressure at the face can also be used to combat external ground water. Guided Boring & Directional Drilling Horizontal Directional Drilling (Guided Boring) is ideal for the underground installation of gas, electric, water, telecommunication or soil remediation lines - without excavation or trenching. Horizontal directional drilling ensures minimal or no environmental disruption and is an excellent choice for installations in diverse rock and soil conditions. Once the pilot bore is completed, a reamer/backreamer is attached to the drill stem string and pulled back -- enlarging the bore wall to comfortably accommodate the product wire, conduit or pipe that is subsequently pulled into place. Rock Boring Rocks can be classified in strength as: soft rock 2,500 to 5000 psi, (17 to 35 mpa) medium rock 5000 to 10,000 psi (35 to 70 mpa) hard rock 10000 psi upwards. Hardest surface rocks being max 40,000 psi (270 Mpa). The key to successful ``Rock Boring`` is by engineering, planning and selection of the correct drilling package knowing the particular ground conditions / rock strengths etc. We can still use the ``Directional Drilling m/c`` but with certain modifications / special tooling, comprising of: drill bit drill motor hole opener / reamer The drill bit is probably the most important of all the tooling. Depending on the rock strength it is usually either roller cone bit, either a TCI (tungsten carbide inserts) or milled tooth diamond. These hole openers rotate at only 50 to 100 rpm. Optimum penetration rates are achieved by operating the "Drill Motor" at the recommended flow rate for Drill Bit size (diameter). This mud flow rate is dictated by; mud pump flow rate bore diameter of drill rods Drill Rods as well as having a large enough bore for the mud flow should also be have enough strength for the rotary torque and the pull back of the Hole Openers /pipe weight. Guidance of the "Pilot Bore" is either a "walk-over" or remote "wire line" tracking system as is normally used with Horizontal Direction Drilling. Cable Pulling Cable pulling is the oldest method of inserting a cable into existing ducting. This entails feeding a winch rope through the ducting and attaching it to the cable with a compression sleeve or sock. As the cable is winched into the ducting the sock tightens its grip on the cable. On larger cables a cable pusher is used to assist the winch and thus reduce tension in the cable. Cable Blow in Systems Cable blowing is used to insert relatively small diameter, light weight electric or fibre optic cables into existing ducting. Compressed air is introduced into the duct and the velocity of the air moves the cable. This is particularly relevant to fibre optic cables. LOCATION, DETECTION & INSPECTION There are various systems involved in location, detection and inspection of underground tunnels and infrastructure, including: Ground Probing Radar (GPR) The first ground penetrating radar survey was performed in Austria in 1929 to sound the depth of a glacier. Since then its development has permitted extensive use in many sectors of industry from utilities to archaeology. GPR uses electromagnetic wave propagation and scattering to image, locate and quantitatively identify changes in electrical and magnetic properties in the ground (Olhoeft, 2000). The resolution of the image produced depends on the ground strata but with favourable conditions it is in the magnitude of ustomize s. Mapping & GIS Most if not all Utilities hold information about their networks electronically. These systems provide the ability to display a utility’s networks in relation to a background map. This allows utilities to hold accurately surveyed information to pinpoint the exact location of their services although data accuracy is still a contentious issue with many utilities. Data in systems such as geographical information systems (GIS) is held as features or objects and each feature can be held as a separate map layer allowing users to ustomize the display. Leak Detection Since its peak in 1994/95 leakage has fallen by a commendable 33% or the equivalent of the daily needs of about 12 million people. The 2001/02 leakage level was down to 146 litres per person per day, the equivalent of 1.5 baths per person per day. Traditional methods can now be supplemented by exciting new techniques such as ground penetrating radar. Intelligent Pigging The purpose of intelligent pigging is to assess the condition of a metallic pipeline. By far the majority of pipeline inspection is on steel pipes with some on Ductile Iron pipe. There is a selection of pigs available to determine different aspects of pipe condition. The loss of wall thickness can be determined, lamination can be detected as can damage to a pipeline. In the majority of instances differential pressure across the pig is used to move it forwards at a controlled speed. On board intelligence records data regarding the pipelines condition and location, which can then be used to locate any faults found from ground level, following down loading of the information at a data gathering facility. EQUIPMENT & MATERIALS pipe handling equipment pipe pushers ancillary pipe equipment PE pipes & fittings clayware pipes & fittings concrete pipes & fittings metal pipes & fittings
The use of pipe & cables installation techniques can reduce environmental impact, social costs and at the same time provide economic alternatives to traditional open cut methods. Pipe & cables installation techniques include:
Micro tunnelling is used here as a general term to describe remotely controlled mechanical tunnelling systems where the spoil is removed from the cutting head within the new pipeline which is advanced by pipe jacking. Micro tunnelling machines have now been developed to work from drive shafts in almost all types of ground conditions. The cutting head has to be carefully selected to deal with the expected ground conditions, with the appropriate cutting tools and crushing devices for the range of gravels, sands, silts, and clays. Water or bentonite may be used to convert the soil into slurry at the cutting face. The slurry is then pumped to the surface where the solids are separated before disposal. Both systems provide face support by mechanical earth pressure balance. Slurry pressure at the face can also be used to combat external ground water.
Horizontal Directional Drilling (Guided Boring) is ideal for the underground installation of gas, electric, water, telecommunication or soil remediation lines - without excavation or trenching. Horizontal directional drilling ensures minimal or no environmental disruption and is an excellent choice for installations in diverse rock and soil conditions. Once the pilot bore is completed, a reamer/backreamer is attached to the drill stem string and pulled back -- enlarging the bore wall to comfortably accommodate the product wire, conduit or pipe that is subsequently pulled into place.
Rocks can be classified in strength as:
Hardest surface rocks being max 40,000 psi (270 Mpa). The key to successful ``Rock Boring`` is by engineering, planning and selection of the correct drilling package knowing the particular ground conditions / rock strengths etc. We can still use the ``Directional Drilling m/c`` but with certain modifications / special tooling, comprising of:
The drill bit is probably the most important of all the tooling. Depending on the rock strength it is usually either roller cone bit, either a TCI (tungsten carbide inserts) or milled tooth diamond. These hole openers rotate at only 50 to 100 rpm. Optimum penetration rates are achieved by operating the "Drill Motor" at the recommended flow rate for Drill Bit size (diameter). This mud flow rate is dictated by;
Drill Rods as well as having a large enough bore for the mud flow should also be have enough strength for the rotary torque and the pull back of the Hole Openers /pipe weight. Guidance of the "Pilot Bore" is either a "walk-over" or remote "wire line" tracking system as is normally used with Horizontal Direction Drilling.
Cable pulling is the oldest method of inserting a cable into existing ducting. This entails feeding a winch rope through the ducting and attaching it to the cable with a compression sleeve or sock. As the cable is winched into the ducting the sock tightens its grip on the cable. On larger cables a cable pusher is used to assist the winch and thus reduce tension in the cable.
Cable blowing is used to insert relatively small diameter, light weight electric or fibre optic cables into existing ducting. Compressed air is introduced into the duct and the velocity of the air moves the cable. This is particularly relevant to fibre optic cables.
LOCATION, DETECTION & INSPECTION
There are various systems involved in location, detection and inspection of underground tunnels and infrastructure, including:
The first ground penetrating radar survey was performed in Austria in 1929 to sound the depth of a glacier. Since then its development has permitted extensive use in many sectors of industry from utilities to archaeology. GPR uses electromagnetic wave propagation and scattering to image, locate and quantitatively identify changes in electrical and magnetic properties in the ground (Olhoeft, 2000). The resolution of the image produced depends on the ground strata but with favourable conditions it is in the magnitude of ustomize s.
Most if not all Utilities hold information about their networks electronically. These systems provide the ability to display a utility’s networks in relation to a background map. This allows utilities to hold accurately surveyed information to pinpoint the exact location of their services although data accuracy is still a contentious issue with many utilities. Data in systems such as geographical information systems (GIS) is held as features or objects and each feature can be held as a separate map layer allowing users to ustomize the display.
Since its peak in 1994/95 leakage has fallen by a commendable 33% or the equivalent of the daily needs of about 12 million people. The 2001/02 leakage level was down to 146 litres per person per day, the equivalent of 1.5 baths per person per day. Traditional methods can now be supplemented by exciting new techniques such as ground penetrating radar.
The purpose of intelligent pigging is to assess the condition of a metallic pipeline. By far the majority of pipeline inspection is on steel pipes with some on Ductile Iron pipe. There is a selection of pigs available to determine different aspects of pipe condition. The loss of wall thickness can be determined, lamination can be detected as can damage to a pipeline. In the majority of instances differential pressure across the pig is used to move it forwards at a controlled speed. On board intelligence records data regarding the pipelines condition and location, which can then be used to locate any faults found from ground level, following down loading of the information at a data gathering facility.
EQUIPMENT & MATERIALS
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