2-MPES 2012 (Application of computerized drill jumbos at the Chenani-Nashri tunnelling site in...

Application of computerized drill jumbos at the Chenani-Nashri tunnelling

site in Jammu-Kashmir, India

H. SCHUNNESSON / LULEÅ UNIVERSITY OF TECHNOLOGYV. POULOPOULOS AND K. BASTIS / LEIGHTON WELLSPUNG

N. PETTERSEN AND A. SHETTY / ATLAS COPCO

MPES 2012November 28-30, New Delhi, India

• part of the planned four-lane widening of the National Highway 1A (NH1A) between Jammu and Srinagar

• The new tunnels will reduce the distance between the two towns by almost 51 km

• The entire mountainous stretch between Jammu and Srinagar passes through steep mountain areas and has significant issues related to weather and safety with frequent slope failures, rock falls and avalanche.

• During the winter 2011/2012 the road was closed for more than 2 months, due to bad weather and geo-mechanical safety problems.

• The tunnel has a maximum overburden of 1050 m. The remote location of the tunnel in the Himalayan mountain ranges with complex geology and logistic constraints raise several engineering and management challenges to the contractors.

Application of computerized drill jumbos at the Chenani-Nashri tunnelling site in Jammu-Kashmir, India

National Highway 1A (NH1A) between Jammu and Srinagar

Bench

Gallery

The Chenani Nashri Tunnel project involves construction of an 8900 m two lane main tunnel (13.3 m diameter) along with a parallel escape tunnel (5 m diameter) from Chenani (south portal) to Nashri (north portal)

• The tunnels are being constructed by the New Austrian Tunnelling Method (NATM).

• Construction of the tunnel began in September 2011 and is expected to be completed by 2015.


The main tunnel is excavated by fully automated 3-boom rigs (Boomer XE3) from Atlas Copco

With a computerised control (RCS) system


Rock Mass CharacterisationMeasurement While Drilling (MWD) During Production Drilling


MWD-technique (data logging)

What is the rock conditions? Is the rock stable?

Is the pre-investigation reliable?What reinforcement is required?

MWD Parameters are: Penetration rate cm/min Feed pressure bar Percussive pressure bar Rotation pressure bar Rotation speed rpm Damper pressure bar Water pressure bar Water flow lit/min

Minimum logging interval 2 cm.(Data are measured every 100 ms and presented as an average over the specified interval)


MWD Logging have been possible for several years! But what do we log???

Rock massproperties

RCSAnti jamming etc.

GeometriesHole lengthEtc.

Drill parameters such as: Percussive pressure Feed pressure Rotation Etc.

Logged penetration rate

Operator

Hole length

Pene

trati

on ra

te


Rock hardness The parameter rock hardness is based on the penetration rate, that has been compensated for variations in hole length and in other drill parameters such as percussive pressure, feed pressure etc.

Hole length

Pene

trati

on ra

te

The Rock hardness parameter is un-calibrated meaning that is has to be customized for local, site specific rock conditions.


Rock fracturing

Hole length (m)

Pene

trati

on ra

te (m

/min

)

0 1 2 3 4 5 6 7 8 9

0.0

0.5

1.0

1.5

2.0

Homogeneous rockFractured rock

The parameter rock fracturing is based the variation of the penetration rate curve and rotation pressure curve

The Rock fracturing parameter is un-calibrated meaning that is has to be customized for local, site specific rock conditions.


Round hole Bolt hole Injection holes

MWD for different holes


Sections of rock along the tunnel form the foundation for graphical maps.

tunnel slicing





Calibration

Geological mappingFracture mappingSchmidt-Hammer testsRock testingUni-axial compressive strengthOther tests


Calibration

140 MPa 55 MPa100 MPa

Calibration


Calibration



The most common rock types along the tunnel stretch are sandstone, siltstone and clay stone.

The sandstone is normally competent with compressive strength in the range of 50-180 MPa. The siltstone is also fairly competent with a compressive strength in the range of 40-80 MPa. Clay stone on the other hand have sometimes very low compressive strength below 10 MPa.

Sand stone

Silt stoneClay stone

0 MPa 50 Mpa 100 Mpa 150 Mpa 200 MPa



Round hole Bolt hole Injection holes

MWD for different holes




Soft rock

Hard rock

Hard rock


• Today, the market for mining equipment is changing and new demands require new options and functions. As a result of the increased demand for automation, the equipment is regarded as only part of an integrated production system rather than the system as a whole.

• The risks and cost due to a mismatch between tunnel design and the construction can be minimised with modern computerised planning tools and drill rigs.

• In the Chenani-Nashri tunnel project this new technologies have been taken to the edge, providing the management an efficient tool to achieve a high quality tunnel and an efficient tunnelling operation.


Many thanks to:

Leighton Welspung Contractors Pvt. Ltd.For allowing us to publish data from the Chenani-Nashri tunnelling project.


Date post:	12-Apr-2017
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2-MPES 2012 (Application of computerized drill jumbos at the Chenani-Nashri tunnelling site in...

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