Controlling vibration due to rock socketing

[KCRatnayake]

I have to solve above specific problem at earliest. Client is going to build a highrise building 5m away from his 7-storeyed existing building. His prime requirement is to keep the vibration level at 0.1g as he's having some delicate communication equipment inside the existing building.

Piling contractors indicated me that this is not possible during rock socketing. Can you please guide me to solve this problem? Details are given below.

Depth to rock = 17m
Pile diameter = 1800mm
Location = Sri Lanka


Thanks,
Clefcon

 

[jdonville]

clefcon,

Drilling the socket will produce some vibration. Suggest that the delicate equipment be removed or shut down during this work, or at least until it can be shown that vibration will not exceed the limit based on monitoring.

A demonstration excavation with monitoring at a more remote location will let you know just what kind of vibrations to expect.

Jeff

 

[lallatin]

Your only problems are a client and a contractor playing CYA. The magnitude of any vibration from a boring operation even centimeters from the foundation of a seven-story building are infiniticimal. Do not waste money on this issue.

 

[BigHarvey]

If you use a chisel for rock socketing, you will induce vibrations. We did lots of measurement on a diaphragm wall in limestone in France. peak particle velocities were maximum 5 mm/s at a distance of 5 m and 0.2 mm/s at 20 m. The chisel was weighing 5.5Tons and UCS of limestone was around 20 MPa. I believe it is not an issue and it certainly should not be one if it's the same owner for both buildings !

 

[KCRatnayake]

BigHarvey,
Can you little bit elaborate on peak paticle velocity please?

Clefcon

 

[BigHarvey]

you have 3 ways of defining vibrations : acceleration, velocity and amplitude ( going from one to the other is just a mathematical process ). When you talk about safe criteria for structures they are generally given in terms of velocity. Rule of thumb for blasting is generally not to exceed a peak particle velocity of 1 inch per second for normal constructions

 

[KCRatnayake]

Thanks