Trenchless technology is a type of subsurface construction work that requires few trenches or no continuous trenches. Trenchless technology is the science of installing, repairing and renewing underground Pipes, ducts and cables using techniques which minimize or eliminate the need for excavation. It can reduce environmental damage, Social costs and produce an alternative to open trench method of installation, renewal and repair it includes in, development of all kinds of underground napping techniques, tunnelling devices and specialist materials and equipment.
It is a rapidly growing sector of the construction and civil engineering industry. It can be defined as a family of methods, materials, and equipment capable of being used for the installation of new or replacement or rehabilitation of existing underground infrastructure with minimal disruption to surface traffic, business, and other activities.
Trenchless Technology Methods
On an overall the trenchless technology methods (TT) can be classified into 2 main divisions:
- Trenchless Construction methods (TCM)
- Trenchless Renewal Methods (TRM)
The trenchless construction methods involve different techniques that are related to the commencement of a new work or new project in underground. It may be a new conduit or pipeline installation in the site or any other new utility. The trenchless renewal methods that facilitate already existing utilities. It may be renewing or rehabilitation or renovation. This work is applied on old, existing utility or pipeline systems that may have some problem with their performance.
Categorisation of Trenchless Renewal Methods
The trenchless technologies, to meet the purpose of renovation are still under development. These methods possess the key features to give a new life to an existing utility system. They can be used to:
- Enlarge pipe systems
The trenchless renewal method involves the following types:
- Underground coatings and linings
- Modified Slip lining
- Close-fit pipe
- In-line replacement
- Cured-in-place pipe
- Slip lining
- Localized Repair
- Lateral Renewal
- Thermoformed Pipe
- Sewer manhole renewal
- The need of the system
In general, trenchless technology minimizes highway damage, environmental impacts, and traffic problems. The disadvantages and difficulties encountered in conventional trenching methods have resulted in thinking of the need for trenchless technology. The advantages of the no-dig technology are also responsible for the need of this technology to be adopted in mainly urban areas. Disadvantage of Open trench methods the open trench is going to create obstruction roads, busy areas, diversions have to be provided before the start of any digging work. As the obstruction is created, the traffic has to be rerouted causing traffic jams. Many a time, while cutting deep trenches in congested areas appear in the adjacent buildings. Another difficulty, which is encountered very often is the damage caused to other service lines or cables present underground. While cutting open trenches, trees, shrubs, gardens etc. may have to be destroyed damaging the environment.
- Reduces the damage of valuable surface
- Reduces the danger of improperly compacted excavations saves resources is accident-free avoids traffic and saves underground space
- Reduces the impact on the environment
- Provides a hassle-free road surface Conclusion
By adopting this technology we can successfully implement pipes under the surface without making any disruptions to the environment and public.
Parameters of Trenchless Construction
Irrespective of the type of construction project, the trenchless construction or renewal methods depends upon certain factors or parameter. They are:
- Type of application
- Range of work in diameter
- Maximum length of installation
Why is No-Dig and Trenchless Technology Important?
Trenchless technology has come a long way over the last few years, and many underground maintenance and repair jobs can now be completed without the need for any extensive excavation. Trenchless technology has a number of potential benefits that come with not having to conduct extensive excavations. Trenchless technology represents a number of different methods and specialized pieces of equipment meant to allow access to underground utilities, such as sewer lines or electrical lines, without disturbing much of the surface area. Generally these processes involve the boring of small and precisely located holes that provide direct access to an affected area, without the need to expose the entire underground utility. This technology is often used in sewer line repair, where an old pipe is repaired by pulling a slip through its interior to plug any holes or a brand new pipe is pulled through as the old one is burst using a special bursting head.
While trenchless technology is not always cheaper than excavating, it often can be. The more that you need to excavate, the more expensive it is going to be. In addition, the cost only increases with the value of what you need to excavate and replace, from roads and parking lots to gardens and structures. Trenchless technology can often offer big savings by allowing an underground task to be completed without the need for potentially expensive excavation.
Not only can excavation be expensive, but it can also take a lot of time. Preparing the area, performing the excavation, filling the excavated area back in and restoring the area above the surface can take days or even weeks in some cases. Trenchless technologies allow you to skip a lot of time and mess associated with excavations, particularly when it is done in a busy or high-value area, like a street or garden.
One of the benefits of trenchless technology that is often overlooked is the safety advantages that it offers. Excavation is messy and dangerous work. Moreover, this danger extends far beyond just the contractors who are working in the area. The danger can extend to your family, pets, property and neighbours. Any large and messy hole in the ground is basically an accident or a lawsuit waiting to happen, so avoiding this problem altogether is often a major advantage of trenchless technology.
Thee technology is becoming more appealing today as a cost-effective way to get things done. The use of trenchless is growing exponentially each year, which is a great thing. Municipalities are learning how to stretch the money they have to spend.
The rapid growth of urban population coupled with the reducing subsurface, as well as ground spaces for laying utilities, are the base catalysts for the application of trenchless techniques in India and other nations of South Asia.
Added to this, the deteriorating state of existing physical subsurface infrastructure evolves into a situation where the conventions are giving way to advancements – trenchless technologies.
In India 10 years ago, the trenchless technique was a term known only for advancements and automation and the information in subsurface construction. Even that knowledge at the time was rather bookish. During the last decade, Indian Trenchless markets have seen a substantial growth in the population of drilling rigs – in fact, the population grew from non-existence to the current total of more than 400 operating units.
Similarly, lining businesses, which started with a few meters of demonstration applications, have evolved into businesses worth millions of dollars. A recent project executed in New Delhi boasts of CIPP lining with diameters up to 1,900 mm with an approximate length of 7 km. A substantial amount of glass-fibre reinforced pipe (GRP) linings have also been executed during this period and at times, it serves as a cost-effective alternative to CIPP.
Indian Subsurface infrastructure has a varied age, starting from newly laid pipes tones that are as old as 200 years. Lengthwise, New Delhi has one of the largest subsurface pipe networks with approximately 5,000 km in length. There are functional sewers in old cities such as Benaras, Kolkata or Mumbai, with pipe ages exceeding 100 years.
In New Delhi, the lines are not only silted but settlements of the crown and other structural failures are rampant in some of the other locations. In some of the cities, such as Coimbatore, another type of problem is the ageing of the pipes where the pipe materials have completely failed.
Apart from the above problems, another difficulty dogging the Indian Subsurface networks is at times the failure of proper grades for gravity lines, necessitating an all-weather round pumping due to sluggish flow. Moreover, the present state of affairs is that after an extremely long period of neglect, now the utility service providers have started feeling the pinch as to the failure of the networks, which are now leading to serious environmental disasters.
One prominent example is the of the Yamuna River. Faced with such situations all over, several utility services providing authorities have embarked upon Environmental Improvement Projects (EIPs). Some of the examples are Rajasthan Urban Infrastructure Development Project (RUIDP), Tamil Nadu Urban Development Project-III (TNUDP-III), Kolkata Environmental Improvement Project (KEIP), etc.These are from Gurgaon, a town in the National Capital Region where the road has settled and cars fell into the ditch one after the another.
With trenchless technology, underground utilities can be installed, replaced or renewed with minimal excavation and disruption to residents, businesses and traffic. Trenchless construction techniques are often more environmentally sensitive and cost effective than traditional surface excavation methods, and can be used in fragile environments where open-cut is not an option. Trenchless technologies have proven effective for numerous utility applications, including water, sewer, gas, industrial, electrical and fiber optics.
Application-wise, the largest need for trenchless techniques is in the water and sewer sector, where the networks are either failing badly or deteriorated to an extent where new installations are becoming a necessity. There are, however, lines where rehabilitation work can still be done and even this work is substantial.
An interesting fact to note is that although India has a large population of drilling rigs, micro-tunnelling machines are still few and far between – despite the huge need for them. For an example, in New Delhi alone a substantial length of various diameter pipelines needs to be installed by microtunneling and pipe jacking methods, as open-cut has been completely ruled out in those cases.
The next popular application of trenchless is in the oil and the gas sectors, where the networks are not as old as the water and sewer lines and are presently under development. Naturally, in this case, the new installation techniques are more applicable and some of the new drilling rigs of larger size and push/pullback capabilities have started arriving in India because of these projects.
One such job under construction is at Paradeep in Orissa. With the growth of oil and gas pipeline networks, such projects are expected to continue to increase. Although the lines for oil and gas are not that old, there are lines like HBJ, where the rehabilitation need is apparent. The Indian Society for Trenchless Technology (INDSTT) has been interacting with different project owners and service providers and has been promoting the application of trenchless techniques in all such projects.
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