Month: February 2020

18 Safety Precautions in Tunnelling

Tunnelling is an underground construction and there are many types of risks during construction. Therefore, it is essential to take measures to protect the workers from accidents. Following are the 18 Safety Precautions in Tunnelling.

1. The floor of the tunnel should be kept dry and clean.
2. Open flames, electric short-circuiting should be avoided by providing proper covering over the power line and light.

3. Medical equipment and doctors should always be available at the site.

4. Fire fighting equipment with an excellent operator and sufficient water supply should be available at the site at all times.

5. Light and electric lines need to be entirely secured and insulated.

6. Unnecessary machines, tools, and construction material should be avoided to store in the tunnel.
7. All the machines and tools should be maintained in usable condition.

Read Also: Basic Construction Tools List

8. Working platforms should be checked periodically.

9. The communication system (like; a telephone) should be installed inside the tunnels for receiving and sending important information about tunnel conditions.

10. All the internal systems like communication systems, power systems, safety devices, and lighting should be checked periodically.

11. The double power supply should be provided so that the power from the standby unit can be restored during the power failure of one power supply.

12. Removal of rock protrusions by immediate hammering in the wake of blasting is known as scaling. The hammer stroke sound must be hard, not hollow. The hollow sound means loose rock.

13. Every worker must be aware of their safety.

14. Protective clothing, steel helmet, rubber gloves, goggles, etc. should be put on by every worker during their work.

15. The proper ventilation system should be provided in the tunnel as required.

16. Proper drainage must be provided.

17. Safety signboards should be provided at various places along the tunnel.

18. Without permission, no unauthorized person should be permitted to enter the tunnel.

Read More:

Maintenance of Railway Tunnels

Shapes of Tunnels

Classification of tunnel Drainage System

Maintenance of Railway Tunnels

Generally, P.W.I. inspects every tunnel in his section, and he is personally responsible for maintaining the track through tunnel in perfect running condition. The following points should be noted in connection with the maintenance of railway tunnels.

1. It should be noticed whether the structure of the tunnel has weakened, cracked or deteriorated.

2. Any type of movement of the masonry parts should be noticed.

3. Under the safety of engineering signals, the maintenance of tunnels should be carried out.

4. The track through the tunnel should be in line and level.

5. The P.W.I is liable for the safety of trains and the protection of men who are employed for the maintenance of railway tunnels.

6. The dimensions of the tunnel section should conform to the original dimension.

7. The tunnel tracks’ renewal work should be performed with the utmost priority.

8. The side drains of the tunnel should be cleaned periodically.

9. Light and power lines should be checked to ensure they are properly insulated.

10. It should assure that the tunnel ventilation system is working properly.

11. All weep holes should be cleaned properly.

12. The ventilation shaft should be kept free from growth of vegetation.

13. The precautions to prevent any leakage through masonry joints should be taken.

14. The position of level pillars should be monitored periodically.

15. To avoid the effect of corrosion of rails and sleepers should be examined periodically.

16. The lining of the tunnel should be examined.

17. It should be concerned that unwanted machines, tools, and construction materials are not stored in the tunnel.

Different Shapes of Tunnels

Safety Precaution in Tunnelling

Ash Pits in Railway Locomotives

It is essential to remove ashes from a locomotive boiler at frequent intervals. The ash pits are provided to receive the ashes from the locomotives. They are usually rectangular in shape.

The depth of an ash pit is around 1.067 m or slightly more or less than this value, and the length is kept slightly more than the length of the longest engine expected to use the ash pits.

The rails are fixed on longitudinal beams provided at the top of the walls. The beams may be of steel, concrete or timber. The timber beams should be well protected against the heating effect of ashes.

The ashes which are collected in the ash-pits should be as possible as early removed from there. For this purpose, a proper drainage system and the required water supply should be provided.

The bottom surface of the ash-pits should be given sufficient slope so that water can be taken out by sump and drain arrangement.

Sometimes the ash pits are located near the water column so that the locomotives can dispose off ashes while taking over water from the water column.

Read More:

Loop line in Railway

Types of Railway Platform

Classification of Tunnel Drainage System

Tunnel Drainage systems are classified as:

(1) Drainage system provided at the time of construction or temporary drainage system.
(2) Drainage system provided in completed tunnels or permanent drainage system.

Classification of Tunnel Drainage System

(1) Temporary Drainage System

This is provided to remove groundwater from the tunnel at the time of construction. In this system, water is removed either by (i) Open-ditch drainage system or (ii) Pumping system.

a) Open Ditch Drainage System:

In this system, water is collected and removed in open ditches, laid with proper slopes at some distance away from the place of work. The open drains or ditches are constructed along the tunnel on both sides at the invert. This drainage system is suitable for rock bases and water-resistant soil.

b) Pumping System:

In this system, sumps are constructed at regular intervals of around 300 m to 500 m. The water is collected in the sumps and is pumped out. For pumping the water, any types of centrifugal pump could be used.

(2) Permanent Drainage System

Permanent Drainage System is provided in one of the following methods:

a) By providing a central Drain

In this system, a central drain is provided between two railway tracks or under the road pavement. It should have sufficient capacity to control the expected water in the tunnel. It should be provided with facilities for inspection and clearing. Inspection manholes should be provided at a distance of 30 m to 50 m.

b) By providing Side Drains

This system is effective for single lane road or railway tunnel where the volume of water to be drained is small. In this system, drains are constructed on either side of the railway track or on the road.

c) By providing corrugated iron shed and side drains

This is provided in tunnels in which water leaks from the roof and side walls of tunnels. By providing corrugated iron shed, shaped to the contour of the roof, water is prevented from dropping on the pavement or railway track. The corrugated shed guides the water to the side drains and is drained out.

Read More:

Shapes of Tunnels

Methods of Ventilation in Tunnels

Necessity of Tunnels

Linoleum Flooring | Building Construction

Linoleum Flooring

Linoleum flooring is used as a covering, mostly laid over concrete or wooden floors to get more attractive looks of the floor.

The linoleum flooring material is formed by mixing linseed oil, pigments, gums, cork dust, resin, wood flour and other filling materials in a correct proportion.

It is available in a variety of colours, printed on both sides, in a rolling form. The width of the linoleum flooring varies from 180 cm to 362 cm, and thickness varies from 2 mm to 7 mm.

Higher thicknesses( 5 to 7 mm) are preferable in the place where the traffic movement is heavy, like in the hospital, cinema hall, public sector, theatre etc. Linoleum tiles are also available in the market.

Read Also: Different Types of Flooring

Advantages

Following are the advantages of linoleum flooring

1. The linoleum flooring material is cheap.
2. It is durable.
3. It gives an attractive look.
4. It reduces noise to a considerable extent.
5. This floor is comfortable for the users.
6. It can be easily cleaned.

Disadvantages

1. It is not suitable for the wet or moist place, because it is subjected to rotting when kept wet.

Read More:

Weight of Rail Per Meter Length in India & Maximum axle Load

Weight of Rail Per Meter Length in India

Rails are usually specified by their weight. If any rail has a section XR, it implies that the weight of the rail section per meter length is X kg.

For example, 35 R rail section means the wight of the rail section per meter length is 35 kg, and same as for 55 R, 45 R, 30 R, 25 R rails section.

Weight of Rail Per Meter Length in India & Maximum axle Load

Following are the standard rail sections with their weight as per Indian Railway.

S. No	Gauge	Rail Section	Weight (kg per meter)
1.	Broad Gauge(B.G)	55 R 45 R 35 R	55 45 35
2.	Meter Gauge(M.G)	35 R 30 R 25 R	35 30 25
3.	Narrow Gauge(N.G)	25 R	25

In India, 45 kg weight rail for B.G and 25 to 30 Kg weight rails for M.G are used.

It is proved experimentally that 55 kg/m rail is more suitable than a 45 kg/m rail for B.G. track.

How to determine the Maximum Axle load?

The axle loads on locomotives directly depend on the weight of rails used in the track. Following is the rule used for determining the maximum axle load of a given rail section.

Maximum axle load = 512 * Weight of rail section in kg per meter or Ibs per yard.

For Example: 45 R rail section

In this case, the weight of the rail section will be 45 kg per meter. Hence, the maximum axle load = 512 * 45 = 23040 kg = 23.04 tonnes.

Read More:

Size and Section of Railway Ballast

Types of Rail Section

Switch Angle in Railway

Railway Water Columns

The water columns in the railway are provided to supply water to the locomotives. Two or more water columns may be installed for a single station, it depends on their importance and requirements.

The water columns should be placed in such a way that traffic is not obstructed by them. The water columns bring water from an overhead tank.

The various parts of a water column are shown in the above picture. A horizontal pipe can be located around the vertical pipe, in a horizontal plane, and a foot valve is fitted with the verticle pipe to regulate the quantity of water. The bag hose directs the water to fall into the tank of the locomotive.

The water columns are usually installed near ash-pits so that ashes can be removed from the engine when it is taking water from the water column. The height of the water column is about 4.42 m from the ground level, and its projection from the verticle pipe is about 2.55 m.

Read More:

Railway Turntable

Railway Triangle

Ash Pits in Railway

Railway Turntable

The railway turntable is constructed for changing the direction of the rail engine. Triangle and turntable are used for the same purposes but the cost of construction is different. Turntable installation is more costly than a triangle track junction. However, it is possible to construct at important stations where space available is limited. The railway turntable is circular in shape and installed in a circular pit.

A turntable consists of a track on a level platform which is supported by a pair of girders. the girders are fixed on a central pivot. There are two or more tracks radiate from the circumference of the pit circle.

When the direction of an engine is to be changed, the engine is brought on the turntable, and after loosening the locking keys, the turntable is rotated with a certain mechanism. After a rotation of 180 degrees, it is then placed on the same tracks or on any other track with exact rotation as needed.

The diameter of the turntable depends on the length of the engine. Hence, the diameter should be long enough to accommodate the longest engine feasible to use the turntable. In India, usually, the length of the turntable is 19.8 metres, but some turntables are 25.91 metres in length as well.

Read More:

Switch Angle in Railway

Angle of Crossing in Railway

Loop line in Railway

Benching – Excavation or Cutting

Benching

The art of cutting side slopes in steps is called benching. When the embankment is constructed on hillside slopes, it is necessary to bench the surface of the hill slope to add stability to the slope.

These benches should have a gentle fall towards the hillsides. Thus benching reduces the probability of sides of slopes.

Read More:

Borrow Pits

Spoil Bank

What is Spoil Bank? Earthwork

Spoil Bank

The bank constructed from surplus excavated earth on the side cutting parallel to the road alignment or main canal bank is known as a spoil bank.

In other words, when the excavated earth is not completely required for the forming of the canal bank or the road embankment. In such a case, the extra earth is deposited in the form of small banks which are known as spoil banks.

The height of the spoil bank should be nearly 1.5 m. They should be constructed at a distance of 3 m from the top edge of the cutting.

The spoil bank is not continuous along the main bank, adequate spaces are left between the two adjacent spoil banks for proper drainage.

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Turfing

How much is PMP certification

Lead an d Lift in Earthwork

Procedure For Doing Earthwork in Embankment