Tunel pdf

History has seen the evolution of tunneling starting with cave formation, for water management, under ground transportation, mineral extraction and for warfare purposes. Initially hand dug with crude tools like chisels, Hammers, spades and shovels, the civil engineering tunneling technology has seen progress in leaps and bounds.

The ever increasing needs of the modern human race have driven the tunneling technology to its pinnacle. This is being realized through rapid advancements in terms of geological and hydro-geological engineering, tunnel design, capacity, construction methods and speed and maintenance during operations.

Safety during construction and operations is getting integrated in all aspects through conscious and educated decisions. In most of the cases tunnel construction is expensive but it saves time and provides comfort. Large excavation of soil or rock etc. With the availability of modern equipment, excavation and backfilling has become easier. In this paper we will explore some advanced methods of tunneling.

TBM is nothing but an inbuilt underground factory which carries out all the activities Shotcreteing, rock bolting and many more required during the construction, for a stable tunnel. TBMs are large machines that tunnel through ground, progressively installing concrete linings, to support the excavated tunnel. Excavated material is transported through the machine to the surface, for removal by trucks. TBMs are typically used in the construction of underground tunnels.

They are tailored for specific ground conditions and are more than meters long and weigh up to 1, tones. TBM is designed based on the geological conditions, for hard rock condition, soft rock conditions or mixed conditions requirement torque, thrust type cutter head and many parameters are different.

So, to predetermine the type and specifications of the TBM study of geology is of utmost importance. If the TBM is not powerful enough for the rock the machine will be overstressed and be prone to breakdown.

Similar to an electric drill the TBM operated by using the thrust and torque. Like the drill, the motor rotates the cutter head, whereas the thrust for the electric drill is provided by the person operating the drill, TBM receives its thrust by cylinders that push the cutter head against the rock face.

TBM gets its forward thrust by pushing against the precast segmental linings. Figure: 1 Shield This component provides the closure to the TBM, it helps in carrying our construction activities inside the TBM as the shield protects the excavated heading portion from collapsing inside the machine. This shield provides safety for the workers inside the machine. Cylinders These cylinders provide thrust force for the rotation of the cutter head. Design of these cylinders for the thrust force is very important.

In hard rock conditions thrust force should be sufficient enough to meet the requirement for rotation of cutter heads otherwise overstressing and breakdown of the machine may occur. In soft rock conditions thrust force should not be more or less than its requirement. If thrust is more cutter heads may cut the face in an uneven and non uniform pattern causing change in the alignment of the machine which may get stuck eventually.

Erecting Device This component helps in installation of segmental linings throughout the periphery of the tunnel section. While ring building of the precast or cast in situ segmental linings, there is always one key, which is very critical in its Impact Factor JCC : 4. Key is nothing but a last segmental portion which completes the ring. As space required is minimum it is the most tricky and difficult part.

After installation of segments annular grouting is done to fill the gap between installed segments and the exposed ground face. The type of tool is determined by type or hardness of the rock. In soils or very weak rock, drag type tools are used. For hard rock, disk cutters are used. Disc cutters are the standard TBM cutters used now days. The disc cutter generally consists of solid steel alloy disc with a tapered cutting edge with a replaceable cutting edge of hardened steel around the perimeter.

Following are types of cutter heads: Figure 2: Single Disc Cutters Figure 3: Twin Disk Cutters Figure 4: Centre Disk Cutter Scraper These scrapers consists of buckets which collect the excavated muck which is produced during the excavation by cutting tools.

This muck is collected in the buckets and transported via belt conveyors. Conveying Devices Conveying system in the form of belt conveyors collects the excavated muck collected by scrapers and transports it to the muck deposition yard. Longitudinal joints of every adjacent ring should be staggered. This thrust force is achieved from the thrust action from the previously installed segmental rings, so while designing the segments consideration of this thrust force is very important.

Packers are the interlocking arrangement for every ring which is bolted through the packers. TBM is safer as shield protects the working area and there is no blasting of explosives is involved as it is in NATM, so it is comparatively safer.

Because in TBM blasting activity is not involved there is no concern with vibrations and over break. However use TBM is a costly affair as initial capital cost is high and mobilization time is longer. In NATM no initial capital investment is required and mobilization time is also less.

In TBM operation highly skilled workers are required. The major disadvantage of TBM is its lack of versatility with regards to tunnel shape and its inadaptability in varying or mixed geological conditions. Power requirement is huge and many times TBM as a whole unit cannot be reused in different projects as requirements and demands can be completely different.

Flexibility in the operation and construction works is the main advantage of the NATM technique. It can be used for hard rock conditions, soft rock conditions and for mixed ground conditions as well.

Impact Factor JCC : 4. To have a good idea about the ground conditions bore holes at required locations are taken. Whether, a wedge cut or a burn cut. Charging with Explosives In this process explosives are inserted into the drilled holes and are connected with detonators. Finally all the detonators are connected at one prime connection. Charging and Blasting In this process the prime connection where all the detonators are connected is exploded which consecutively allows the explosion of each explosive placed in each drilled hole at a designed interval generally at 1 millisecond interval.

Scaling and Mucking This process starts after complete removal of the dust and harmful gases which occurred during blasting. In this process loose cuts which remain intact on the face are removed.

NATM has been particularly successful in conditions where complex geological features which cause uncertainties in the prognosis of the rock mass behaviour are encountered The main features of NATM are: a. The lining is form by a flexible combination of rockbolts, wire mesh, steel ribs and a thin layer of shotcrete. It is. Monitoring: Sophisticated instrumentation is installed around the tunnel wall before the first shotcrete lining is placed. It is used to monitor the deformations of the excavation and the build-up of load in the support, so that the lining measures can be increased if necessary.

A submerged tunnel is a sub-aqueous tunnel constructed by the prefabrication of tunnel units and then submerged and jointed on the seabed. It is usually. The first cross harbour tunnel in Hong Kong is made of steel but reinforced concrete ones are preferred now. Reinforced concrete tubes are not only cheaper than steel ones, but can be more easily made in rectangular cross sections, which were more suitable for multi-lane road tunnels. In addition, they can be. The principal operations in construction of submerged tunnels are: 1.

Tunnels units are pre-fabricated in a dry dock. The dry dock is usually an excavated basin beside seashore at a depth several meters below water level. Besides the structural frame, fittings and accessories are installed onto the units. While the tunnel units are pre-fabricated in the dry dock, a trench on the seabed for laying the tunnels units will be prepared at the same time.

The trench may be excavated by dredging or by grabbing. The sides of the trench are usually sloped back to a stable angle. To ensure the stability of the tunnel units on the seabed, the foundation of the tunnel units shall be prepared. There are two methods for the preparation of the foundation: Screeding method, and Sand jetting method Seabed leveller.

Granular trench bedding materials are laid on the trench bed and then smoothed by a leveller. Sand Jetting Method Concrete pads are constructed at suitable locations on the trench bed for supporting hydraulic jacks. The tunnel bedding will be prepared by sand jetting method after the tunnel segment has been placed. The open ends of the units will be closed with watertight temporary steel bulkheads to enable them to float. The floodgate of the casting basin is opened to let the seawater flowing in.

The unit is then floated and towed to its final position. The unit can be laid by fixed-leg platform, or more often nowadays by floating pontoons. In the later case, two pontoons are placed on top of the tunnel unit to be sunk.

There are transit winches on the pontoons for adjusting the position of the pontoons. The wires from the winches are tied to heavy concrete block anchors on the seabed. The sinking operation starts with water ballasting of the. Its position under water is carefully controlled by means of the surveying tower. At an end of each tunnel units, there are a bulkhead with a locating nib, and a Gina gasket or a steel bearing plate installed.

The unit is lowered slowly until the locating nibs are engaged. Now the moving of the unit is taken over by hydraulic jacks. The jacks pulled the newly sunk unit towards its neighbour until sufficient contact pressure is established between the Gina and the bearing plate. This initial compression provides an isolation of the water inside the gap from the outside. Thereafter the water is discharged from the joint. The unbalanced hydrostatic pressure on the further end of the new unit will press the units tightly together.

The bulkheads at the joints are then removed. The waterproofing of the joint is further reinforced by installing an omega seal and covered with a steel plate by welding. Finally the joint is filled with concrete or cement grout. If the tunnel bedding is placed by sand jetting, the sand and water are mixed and pumped down from a barge through deliver pipes to nozzles beneath the tunnel unit which are placed at 4 to 8 m intervals.

Following the sand jetting. Selected backfill comprising of granular material which will compact naturally under water is placed to mid-way of the tunnel depth. General fill or granular fill material which would not cause damages to the tunnel waterproofing is placed on top until a cover of at least 2 m for the tunnel unit is attained. Rock armour should also be provided near the shore for protection of tunnel from damages by vessels. Open navigation menu. Close suggestions Search Search. User Settings.

Skip carousel. Carousel Previous. Carousel Next. What is Scribd? Explore Ebooks. Bestsellers Editors' Picks All Ebooks. Explore Audiobooks. Bestsellers Editors' Picks All audiobooks. Explore Magazines. Editors' Picks All magazines. Explore Podcasts All podcasts. Difficulty Beginner Intermediate Advanced. Explore Documents. Uploaded by ea Document Information click to expand document information Original Title Tunnel.

Did you find this document useful? Is this content inappropriate? Report this Document. Flag for inappropriate content. Download now. Save Save Tunnel. Original Title: Tunnel. Related titles. Carousel Previous Carousel Next.

Jump to Page. Search inside document. Introduction Tunnels can be defined as underground passages constructed for the purpose of transportation connection between two points. Type of Tunnels There are many types of tunnels and can be classified in many ways: Classified by Purpose Example of tunnels Railway tunnels, metro system, highway tunnels, pedestrian tunnels, water tunnels, sewage tunnels, services tunnels, storage tunnels.

Tunnel lining materials Permanent linings are required in most tunnels, always in soft ground and frequently in rock. Sometimes the joints are also caulked with rubberised bituminous strips. Voids behind the preformed segments are filled by bentonite cement grout. Pre-deck method of tunneling R. Pipe Jacking For small diameter pipes, bullet-shaped solid metal heads are fixed to the leading end of the pipe, which is jacked into the ground displacing the earth.

The excavated spoil is Pipe Jacking Method liquefied by mixing with bentonite slurry and removed by pump and pipeline. Shield Tunnelling Method Use of Compressed Air in Tunneling When tunnelling in water bearing ground, ground water infiltration will create problems. Full Face Method In this method, the whole tunnel face is blasted at the same time.

The advantages of this method are that it allows tunnelling in one operation and is efficient. It is essential that the lining remains in full contact with the rock and both deflect together. Submerged Tunnel A submerged tunnel is a sub-aqueous tunnel constructed by the prefabrication of tunnel units and then submerged and jointed on the seabed.

It is usually advantageous to construct submerged tunnel rather than bored tunnel below seabed because a cover of at least 10 m is required for the safe construction of a bored tunnel under seabed. In addition, they can be constructed rather long to reduce the numbers of sinking and jointing operation. There are two methods for the preparation of the foundation: Screeding method, and Sand jetting method Seabed leveller Screeding Method Granular trench bedding materials are laid on the trench bed and then smoothed by a leveller.

Documents Similar To Tunnel. Bhaskar Reddy. Kunal Khubani. Hanamant Hunashikatti. Asim Amin. Mohamed H. Vanu Vamalai. Jasminka Vilotijevic Bozinovic. Bob Moncrieff. Sanket Bansal. Kurt Cargo. Sanjoy Sanyal. Melinda Gordon. Catalin Boroianu. Will Wonka. Prem Sharma. Leslie 'Beau' Dodoo. More From ea Siddeshkn Siddesh. Popular in Engineering. Putra Kusuma Hardito. Anand Kulkarni. Anonymous 10AptpgWG. Aircraft-Simulation-of-Beechcraft-Model 1. Jason Hall.

Carlos Martinez. A review of the past, present and future of the European loss prevention and safety promotion in the process industrie.