What Equipment to excavate rock and best type of foundation 1

[Rakra]

What type of equipment is available for use to excavate a rock with UCS rock strenght of 3.5MPa? Its a calcareous siltstone with cherty nodules. Secondly, most of the site has bedrock at surface. I'm thinking either pad or strip footing with minimum embedment depth of 0.5m into the compentent rock (0-0.5m is moderately weathered)would be ok. Which footing type would be the best option? Also thinking of ease of running utility lines.

Any responses would be appreciated.

 

[dgillette]

I'm not the rock excavation expert, but I suggest you add a bit more information, as follows:

For excavating rock, unconfined strength may not matter much unless the rock is very massive. Far more important are the spacing and orientation of the discontinuities. Commonly, they can make the difference between easy ripping and blasting, but your rock is quite weak (if I converted correctly from MPa to psi, the units to which I am accustomed), so blasting may not be necessary even if the rock is massive.

Another thing that could be important is whether you are excavating to a free face (so you could pull it off with a hoe bucket), or going straight down.

Also, you should say something about the size of the excavation. Is this just for getting to relatively sound rock for the footings? For rockfill borrow? For a basement?