Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.
Tunnelling Tips!
Drilling and blasting in dense urban areas
THINKING
It’s a common practice
Drilling & blasting is common practice
in cities such as Hong Kong due to the large
volume of tunne...
Is it really better to blast?
Blasting methods are proven to be
more effective at removing hard
rock than mechanical excav...
Think before you drill…
There are many considerations
& hazards that you must be aware
of when using this method in highly...
Know what
you’re up
against.
Know your challenges
THINKING
• Proximity - close to many sensitive receivers
• Potential impacts on the community
• Possi...
Know your challenges
• Higher level of confidence required
for approval authorities
• Needs of the community vs rising
con...
Be a step ahead
know your hazards
THINKING
• Ground-borne vibrations
• Fly rock
• Dust and fumes
• Air overpressure
• Expl...
Are you aware of the
Sensitive receivers?
THINKING
• Temporary excavation support
• Public utilities
• Retaining walls and...
Prepare
before you
blast
Prepare before you blast
THINKING
Address your
hazards & sensitive
receivers by
making the
appropriate
considerations…
Take action
Prepare before you blast
THINKING
Ensure monitoring
and control
measures are in
place before you
drill & blast
THINKING
Vibration
monitoring
procedures and
inspections are
to be put in place
Reduction of air
overpressure
needs to be
...
• Explosives delivery and handling procedures
are to be drawn up
• Public notification and traffic management
needs to be ...
THINKING
Prepare before you blast
Ensure Vibration
Prediction work
and Monitoring
procedures are
ready to go
This validate...
This involves…
• Setting vibration limits
• Predicting vibrations acting at sensitive
receivers
• Limiting explosive charg...
THINKING
Prepare before you blast
Know your limits
THINKING
Prepare before you blast
The vibration equation?
Write it up
Write it up
Contractor’s Blasting Assessment Report
This report demonstrates that the blasting works
are feasible without ...
Write it up
Blasting Method Statement (BMS)
THINKING
The contractor will also
need to prepare a
Blasting Method
Statement ...
Blasting Assessment Report (BAR)
needs to be approved by the Mines
Division of the Civil Engineering and
Development Depar...
Measure up
Measuring the vibrations
You need a
minimum of
monitoring stations
for each blast
(MTR projects)
6
What you need
THINKING
Measuring the vibrations
What you need
THINKING
Use a Vibrograph
(velocity seismograph)
to measure and record
PPV and ampl...
AAA
trigger
system
Measuring the vibrations
What you need
THINKING
• Alert
• Action
• Alarm
Contact:
Jack Muir
Associate – Transport
jack.muir@aurecongroup.com
Nick Bedford
Senior Civil Engineer – Transport
nick.be...
Upcoming SlideShare
Loading in …5
×

Tunnelling tips! Drilling and blasting in dense urban areas

14,628 views

Published on

A guide to effective drilling and blasting in dense urban areas that discusses common safety hazards, challenges and sensitive receivers associated with this method.

Published in: Engineering

Tunnelling tips! Drilling and blasting in dense urban areas

  1. 1. Tunnelling Tips! Drilling and blasting in dense urban areas THINKING
  2. 2. It’s a common practice Drilling & blasting is common practice in cities such as Hong Kong due to the large volume of tunnelling work. THINKING
  3. 3. Is it really better to blast? Blasting methods are proven to be more effective at removing hard rock than mechanical excavation. THINKING
  4. 4. Think before you drill… There are many considerations & hazards that you must be aware of when using this method in highly dense areas. THINKING
  5. 5. Know what you’re up against.
  6. 6. Know your challenges THINKING • Proximity - close to many sensitive receivers • Potential impacts on the community • Possible constraints on contractors
  7. 7. Know your challenges • Higher level of confidence required for approval authorities • Needs of the community vs rising construction costs THINKING
  8. 8. Be a step ahead know your hazards THINKING • Ground-borne vibrations • Fly rock • Dust and fumes • Air overpressure • Explosives handling
  9. 9. Are you aware of the Sensitive receivers? THINKING • Temporary excavation support • Public utilities • Retaining walls and cut slopes • Natural terrains • Existing building structures • Piled Foundations • Historic buildings
  10. 10. Prepare before you blast
  11. 11. Prepare before you blast THINKING Address your hazards & sensitive receivers by making the appropriate considerations…
  12. 12. Take action Prepare before you blast THINKING Ensure monitoring and control measures are in place before you drill & blast
  13. 13. THINKING Vibration monitoring procedures and inspections are to be put in place Reduction of air overpressure needs to be considered Physical protection measures are essential Prepare before you blast Take action
  14. 14. • Explosives delivery and handling procedures are to be drawn up • Public notification and traffic management needs to be appropriately planned • Site supervision must be arranged • Blasting Assessment Report (BAR) needs to be written THINKING Take action Prepare before you blast
  15. 15. THINKING Prepare before you blast Ensure Vibration Prediction work and Monitoring procedures are ready to go This validates design predictions & ensures PPV limits are not exceeded
  16. 16. This involves… • Setting vibration limits • Predicting vibrations acting at sensitive receivers • Limiting explosive charge weight • Measuring and recording vibrations THINKING Prepare before you blast Take action
  17. 17. THINKING Prepare before you blast Know your limits
  18. 18. THINKING Prepare before you blast The vibration equation?
  19. 19. Write it up
  20. 20. Write it up Contractor’s Blasting Assessment Report This report demonstrates that the blasting works are feasible without exceeding the impact criteria of nearby sensitive receivers. In this report, you will: • Identify the location and condition of sensitive receivers • Propose allowable vibration limits • Estimate allowable charge weights • Examine possible hazards and adverse consequences • Propose protection measures and safety procedures to ensure that the hazards are controlled THINKING
  21. 21. Write it up Blasting Method Statement (BMS) THINKING The contractor will also need to prepare a Blasting Method Statement (BMS) with specific detail of work sequence, blast design, protective measures, monitoring and contingency plans.
  22. 22. Blasting Assessment Report (BAR) needs to be approved by the Mines Division of the Civil Engineering and Development Department (CEDD) before going ahead. Get it approved THINKING
  23. 23. Measure up
  24. 24. Measuring the vibrations You need a minimum of monitoring stations for each blast (MTR projects) 6 What you need THINKING
  25. 25. Measuring the vibrations What you need THINKING Use a Vibrograph (velocity seismograph) to measure and record PPV and amplitude of ground motion
  26. 26. AAA trigger system Measuring the vibrations What you need THINKING • Alert • Action • Alarm
  27. 27. Contact: Jack Muir Associate – Transport jack.muir@aurecongroup.com Nick Bedford Senior Civil Engineer – Transport nick.bedford@aurecongroup.com Read more on our website!

×