Railway Tunnel Formwork Construction

What is tunnel formwork?

Railway Tunnel Formwork Construction – The tunnel form is a formwork system that allows the contractor to cast walls and slabs in one operation in a daily cycle. It combines the speed, quality and accuracy of factory / off-site production with the flexibility and economy of in-situ manufacturing and is recognized as a modern method of manufacture (MMC).

The result is a cellular reinforced structure, the surfaces of which are sufficiently high quality to require only minimal finishing for straight decoration, while the end walls and facades are easily completed with thermally insulated units that are Can be worn as required.

The system creates an efficient load-bearing structure for use in a wide variety of applications. It is particularly effective in projects suited to repetitive cellular construction such as residential blocks, hotels, student housing, barracks and prisons.

Tunnel Formwork- A Leap from Conservative Formwork System

Tunnel Formwork is that system that allows casting walls and slabs in one operation by the contractor in a daily cycle. The formwork is recognized as a modern method of construction or MMC that involves speed, accuracy of factory/off-site production, quality underpinned with flexibility and cost-cutting measure of in-situ construction. A cellular-like reinforced structure with a sufficiently high quality surface is the final product of the tunnel formwork that requires minimal finishing for direct designing. The end and front walls of the structure are completed with thermally insulated units easily. An efficient load bearing structure is also formed by the system that can be used widely in a variety of applications. The structure is particularly effective in projects that are well-suited to repetitive cellular construction including hotels, barracks, prisons, residential blocks, and student accommodation. Every different customer formwork can be specifically hydraulic formworkor portal type on rails, full round, self-supporting, etc.

Tunnel Formwork- A Progress in Indian Construction Industry

Tunnel formwork is mainly adapted to simplify construction projects. The use of prefabricated forms and reinforcement of cages and the repetitive nature of the system adapts to the building purposes. Tunnel formwork smoothen the operation. The system is well recognized in the industry for its less reliance on skilled labor and faster process with no compromise on the quality of construction. The even steel face of tunnel formwork creates a smooth finish! As a result, the finished product is enhanced with quality with the least preparation required for decoration.

The capability rendered for direct designing reduces the additional cost in following trades and make the process cost effective. Tunnel formwork also provides an integral working platform and cut edge protection system spanned with safety. The flexibility of the system allows minimum tool requirement and equipments, thus, reducing the risk of on-site accidents. The in-situ casting of units and availability of local ready-mixed concrete supplies cut down on transportation impacts.

NPEC- A Leading Tunnel Fabricator in India

Tunnel formwork System is the wind of change from the conventional formwork. With rapid advancement in industrial constructions in India, tunnel formwork can boost efficiency and reduce cost of construction by 40% and time by 60%. When multi-storey construction and repetitive modular structure are becoming an integral part of the construction industry, tunnel formwork has paralleled the conventional concrete method with new formwork techniques and detailed planning. NPEC is the leading tunnel formwork fabricatorthat is ready to make the cut in the Indian construction industry.

We are a Team Providing Cutting-Edge Hydraulic Tunnel Solutions

NPEC is the ultimate hydraulic tunnel fabricator that offers hydraulic tunnel solutions and hydraulic tunnel gantryformwork that suits your project requirements. Our hydraulic tunnels are designed for major dams, vertical shafts, trailrace tunnel, bridges, etc. We are proficient in providing self-reacting system that is hydraulic coupled with a ring nut cylinder that facilitates arming and disarming with no intervention of mechanical tools. NPEC hydraulic tunnel fabricator manufactures in-situ hydraulic tunnel formwork according to the construction requirements- we offer what your dream projects need.

NPEC- Your Most Preferred Railway Tunnel Fabrication Partner

NPEC is specialist in delivering infrastructural tunneling formworks used in making subways and rail tunnels. Our railway tunnel fabricators design railway tunnel solutions to not only replace the manual labor but also focus on the safety facet spanned with efficiency and progressiveness. We design formworks matching the customer’s specifications with cutting edge technology. We have pioneered railway tunnel formworks thatare controlled with hydraulic or electricity applied side wings system that gives way to faster assembly rate by 30%, quicker supply rate, higher installation precision and strength. Our standard railway tunnel formwork increases reutilization ration and improves one-time use to several.

Offering End-to-End Tunneling Solutions Matching Your Requirements

Our engineering solutions inspire innovation and expertise that compensate for low skilled labors within reduced time frame. Enhance the quality of repetitive modular multi-storied construction and infrastructural construction with formwork techniques offered by NPEC- we are the ultimate solution to your tunnel problems. Our cutting-edge services make us the most trusted and dynamic company with strong traditions and clientele base.

Tunnel Formwork System

Tunnel formwork is a system that casts wall and slab concrete together. The system is suitable for home projects, hotels, mall projects and other buildings that replicate architectural details. Use of its structural properties and using wire mesh, the diurnal cycle is allowed for casting. The initial investment of tunnel formwork is expensive compared to classic conventional systems, but 500 times using formwork; The unit formwork cost for solid surface is lower than all systems. When we compared the tunnel formwork system with classical systems, the advantages of the tautunline formwork outweigh the disadvantages.

Tunnel Formwork Benefits

The building

The formwork is specifically adapted for each project. The iterative nature of the system and the use of prefabricated forms and strong mats / cages simplify the entire manufacturing process, leading to a smoother and faster operation. The technologies used are already familiar to the industry, but dependence on skilled labor is low with tunnel construction.


The quality has increased despite the speed of construction. The precise, even steel face of the formwork creates a smooth, high-quality finish capable of achieving straightforward embellishment with minimal preparation (a skim coat may be required). This reduces the need for the following trades, thus providing additional cost savings and speeding up the entire process.

The design

Large blocks constructed using the form of the tunnel provide exceptional flexibility in the design and layout of the building and allow a high degree of freedom in final appearance.


The tunnel farm has an integral working platform and edge protection system. In addition, the repetitive, predictive nature of the tasks involved encourages familiarity with operations, and, once training is completed, productivity improves as construction progresses. The minimum requirement of equipment and equipment while moving as a tunnel minimizes the risk of accidents on site.


The local availability of insulating castings and ready-mix concrete supplies at the site minimizes transportation impacts.

Just-in-time delivery and near zero wastage produces an overall tidier site with associated cost savings and safety benefits.

The thermal mass of concrete combined with the right insulation and boiler design reduces heating costs and can even reduce air conditioning requirements

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Website – http://www.npec.in/

Qustion Asked On Tunnel Formwork

What is Tunnel Formwork?

Tunnel formwork or tunnel construction is a method of underground construction that is done through digging of soil or hard rock. It is a hollow tube or a horizontal passageway situated underground. Tunnels can be created by environmental forces like erosion but manmade tunnels are considred as engineering masterpieces created by the process of excavation. Construction of tunnels is done in a way that ensures its static position during the dead load (weight of the structure) and live load (load created by vehicles and people that transverse through the tunnel).

Tunnels can be used for transportation like canals, road vehicles, trains, subways- for mining purposes- and for conducting water and sewage. Underground excavations that often connect tunnels and shafts are used for underground hydroelectric power plants, pumping stations, storage of oil and water, light manufacturing, etc. Tunnels are a result of planning, the outcome of which is a solution to a specific infrastructural challenge. Tunnel construction is heavily dependent upon the material (hard or soft rock) through which it may pass. Every different material demands unique approach to techniques.

What are the Different Methods of Tunnel Formwork?

Considered as one of the most sophisticated and engineering marvels, Tunnel construction is a challenging job, especially when the methods of building a tunnel depend on unprecedented environmental factors. Every different geological aspect demands unique approach to techniques and specialized methods.

Some of the common methods used for building tunnels are:

1. Cut-and-cover Tunnel:

This is one of the simplest methods of tunnel construction. The tunnel structure is precast in an excavation or cast-in-situ. Cut-and-coverconstruction is ideal for tunnels that are located in shallow depths. This type of tunnel construction method is adopted for building underpasses, tunnels in flat terrain or shallow areas, and approach sections of other tunnels. The excavation is done through the surface without collapsing the excavation walls when it is economically favorable.

Bottom-up and top-down are the two types of Cut-and-coverconstruction.

2. Bored or Mined Tunnel:

Bored Tunnels are constructed without excavating the surface and the tunnels built under this method are named in accordance to the material through which it must be excavated. Reducing time and being usually more economical, bored Tunnel is a predominant type of tunnel formwork system used in-situ for mining operations. Excavation in bored tunneling takes places at the portal, thus, deterring the usual impacts on noise quality, utilities, air, and traffic.

3. Immersed Tube Tunnel:

Immersed tube tunnel is the most commonly used system for underwater tunnel formwork. Consisting of large pre-cast concrete or concrete-filled steel tunnels that are likely to be fabricated in the land and later installed on the submerged bed. After the structure is installed, it is back-filled. Mainly used to sink into a water body or water surface, Immersed tunnels are also installed for rail connections and roads. These tunnels are designed in required lengths in improvised flooded basins or in dry rocks or shipways.

4. Jacked Box Tunnel:

Jacked Box tunneling technique was adopted from pipe jacking technology and is used in soft surface grounds for relatively shorter lengths of tunnels. In such constructions, prefabricated box structures are jacked through the soil horizontally through the clay against a driving wall. This method is used to construct tunnels in railroad embankments and underground runways.

5. Soft Ground Tunnel:

Tunnels that are constructed by excavating soft soil material using a shield or by mining methods like sequential excavation method (SEM) are considered as soft ground tunnels. Ground material may differ from cohesive soils to non-cohesive soils and silty sands.

6. Rock Tunnel:

Tunnels that are constructed through excavation of rocks using the methods of blasting or drilling, are called as Rock tunnels. Mechanized excavators are adopted in this type of tunnel methodology in case of soft rock or sequential excavation method (SEM) or even rock tunnel boring machines are used. Considering the behavior of rocks differing in every location depending on the measures of stabilization that range from no support at all to heavily reinforced concrete lining or a combination of all, this is the most challenging tunneling geology.

What is Lining of Tunnel?

Tunnel lining, a precast concrete segment in the form of rings is the wall formed against the tunnel. The use of precast tunnel lining was patented in 1874 by James Henry Greathead. It is indicated as the finishing touch rendered to the cross section of the tunnel. Tunnel lining as the most fundamental stage of tunnel construction, determines the underground structural strength, durability, safety, and support of the service as well as the final aeration, lighting, and ventilation.

Tunnel Lining is of two types:

Temporary Lining- It is provided during the tunnel construction for lending support to the roof and the walls of tunnel.

Permanent Lining – It is provided in soft clay material, likely to disintegrate. Ideal lining must be economical, durable, easy to build and maintain.

How Tunnel Lining is Done?

Based on the tunneling method used, construction site and conditions available, materials used for tunnel lining may be cast-in-place concrete, cast iron, steel, and prefabricated reinforced concrete. Lining shape and size are defined by the depth, size and function of the tunnel and the type of take-up load (traffic, hydrostatical pressure, rock pressure, structure force, etc). Cast-in-place lining is used for tunnel construction entailing big cross-section and the most complex structure. On the other hand, precast lining is mainly used for shield and erector- mostly in subway tunnels or arm tunneling.

  •  Concrete tunnel lining is carried out in two or three parts- overt, invert and kerb.
  •  Shutter forms of travelling type of suitable length are used for lining of overt of the tunnel.
  •  Concrete lining is done to prevent seepage of water in immersed tunnels.
  •  Concrete Lining is done in portions where rock formation requires additional support for tunnels constructed to be used in traffic.