Tunnel Engineering for Indian Railways

Pir Panjal Tunnel

Pir Panjal Tunnel

The tunnel is almost straight, extending from north to south. It is 8.4m wide and 7.3m high.

Pirpanjal Tunnel

Pir Panjal (or T-80) is India's longest transportation railway tunnel at 10.96km.

The tunnel section is a part of the 202km Udhampur - Srinagar - Baramulla rail link project undertaken by the Northern Railways

Pirpanjal Tunnel

It operates 440m below the existing Jawahar Tunnel, which is the only road link from the region to the rest of India.

Tunnel engineering at a glance

• Topographic survey done for 2000m length and for a width of 100m on either side of centre line of the tunnel

• Resolution with a grid of size 25m x 25m

• Gradient of 1 in 200 adopted in the tunnel throughout for easy drainage

1. Topographic survey

• 9 bore holes with a maximum depth of 51.0m below natural ground level

• Rotary type boring machine with diamond bits was used.

• Jointed basalt (above crown), breccia (in the Tunnel section), Amygdaloidal basalt, volcanic ash (below invert) etc are encountered.

2. Geotechnical investigations

3. Field tests

(a) Electrical resisitivity tests• Current applied in the outer pair of

electrodes• Potential difference measured at the

central pair of electrodes• Resistivity governed by the amount of

pore water and arrange of pores

3. Field tests

(b) Pressure meter tests (Stress – Strain relationship of soil mass and deformation modulus, E)

• Determine rock strength parameters, E for Basalt is 5000 MPa

3. Field tests

(c) Lugeon tests (Permeability characteristics of rock mass

• Permeability values are found to be low.

•Assessment of grouting requirement.

3. Field tests

(d) Seismic Tomography• Fast emerging powerful tool and precise in-situ determination of seismic velocities

• Detailed information about the soil and rockmass properties

• Separation of drill bore holes not more than 60m to give better resolution

4. Tunnel Design

Design parameters:1.Density2.Water absorption3.UCS4.Core recovery5. RQD6.E value7.Tensile strength8.RMR9.Q value

Tunnelling Video

Manual

Tunnel Boring Machine

TUNNELS IN SOUTH CENTRAL RAILWAY

• Tunnel length: 1500 RM

Construction of BG Single line Railway Tunnel between Margutti (H) and Kamalapur stations In Bidar – Gulabarga section

Tunnel layout

Main tunnel

Escape tunnel

Trolley refuge at every 100m

AREA-55.19 sqm

area:25.94 sqm

Tunnel radio system VIDEO

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