Which is the best method for lining of concrete tunnel?
Steel ribs, bars etc are used for thick concrete lining. Form-work for the tunnel is made up of steel or wood or combination of both. The form should be designed so as to resist the pressure of the concrete during its placement.
What is used for lining the tunnel?
The basic materials for tunnel lining construction are cast-in-place concrete, cast-in-place and prefabricated reinforced concrete, cast iron and steel. These materials are chosen according to conditions of construction area and tunnelling methods.
Why steel fiber reinforced concrete is used in tunnel lining?
The production process of the segments is simpler and the formation of cracks during handling and installation is distinctly reduced. Due to their higher resistance against corrosion and cracking stresses as well as their great impact toughness, the segments are more durable.
What are the types of tunnel lining?
1. Tunnel lining type
- (1) Spray anchor support (lining)
- (2) Integral lining.
- (3) Compound lining.
Why concrete lining is high quality lining?
Steel and ductile iron pipes can be lined with cement-sand mortar or spun concrete and these form some of the best and most cost effective types of interior protection. The cement mortar or concrete lining generates a high pH environment which passivates the metal and prevents corrosion.
What is concrete tunnel lining?
Sprayed concrete is used to provide temporary support for tunnels through weak rock, stabilising the rock by filling crack and openings. It also seals the surface, preventing water ingress.
What is meant by tunnel lining?
i. The timber, brick, concrete, or steel supports erected in a tunnel to maintain dimensions and safe working conditions.
What is tunnel ventilation?
The typical feature of a tunnel ventilation system is the fans installed in the rear gable of a house and an air inlet at the front of the house, or vice versa. This configuration causes the so-called tunnel effect where air flows over the animals at great speed.
What is benching in tunnel?
In large tunnels and when the quality of the rock is not satisfactory, heading and benching method is often used. This method involves the driving the top portion of the tunnel in advance of the bottom portion. The lining of roof arch can then be constructed first by using the bottom bench as temporary supports.
What are the requirements of good lining?
Following are the essential properties of a good lining: The lining should be strong and durable. Initial cost of lining and its subsequent maintenance cost should be low. The lining should not get damaged by tramping of cattles. It should resist growth of weeds and attack of burrowing animals.
What is concrete lining?
Concrete canal lining is often used due to its high structural strength and longevity. Concrete used for canal lining is typically non-reinforced, as a way to reduce cost. A common method for constructing concrete lining is the use of slip forms, which are drawn down the length of the canal as the concrete is poured.
What is the purpose of tunnel lining?
Tunnel lining is a permanent support structure built with reinforced concrete and other materials along the periphery of the tunnel body to prevent deformation or collapse of the surrounding rock. After the tunnel is excavated, in order to maintain the stability of the surrounding rock, support (lining) is generally required.
Can straight wall lining be used in a tunnel?
When in a tunnel, most of the surrounding rock is below grade 4, and only a few sections are grade IV wall rock, straight wall lining can also be used. Straight wall lining is composed of three parts: upper arch ring, vertical side walls on both sides and bottom bottom.
What type of boron lining should be used in highway tunnels?
Among the three types of spray anchor support (lining), integral lining and complex table lining, the type of boron lining used in highway tunnels should depend on the surrounding rock geological conditions, construction conditions and use requirements.
What is the excavation width of a typical tunnel?
For modern highway tunnels, the excavation width is generally 10m ~ 20m, and the excavation section is 80m2 ~ 150m2.