Unconsolidated gravels, cobbles, boulders - Coastal Wharf project
Unconsolidated gravels, cobbles, boulders - Coastal Wharf project
(OP)
Hi everyone, I have a site with about 5m thick Silty Clay / Sandy Clay overlying Unconsolidated gravels, sands, cobbles/boulders. We did drilling (wash boring and HQ coring) with SPT, most refusing on cobbles/boulders at depth. size of cobbles/boulders is unknown. In addition, the unconsolidated sediments are subject to active movements due to submarine landslide (underwater slides) off the adjacent coastline. My question is, what are my foundation options for wharf construction? basis of ultimate bearing capacity? groundwater/seawater is at 0 to 1m below ground surface. Any thoughts / experience sharing would be appreciated.
RE: Unconsolidated gravels, cobbles, boulders - Coastal Wharf project
When you say "...most refusing on cobbles/boulders at depth" I assume you are referring to your SPTs- you then go on to say the "size of cobbles/boulders is unknown".
If you cored into the cobbles and boulders (HQ coring), how is their size not known? Surely the size of the cored dimension was measured?
If you mean to say that your boreholes were terminated at the top of the cobble/boulder horizon, and given the documented activity in the area, I would strongly suggest you obtain a full profile before speculating on foundation types...you need to ensure your foundations are taken into something stable, as opposed to just considering bearing capacity etc. - go and core through the boulders down to bedrock in at least a few strategically-spaced borings!
All the best,
Mike
RE: Unconsolidated gravels, cobbles, boulders - Coastal Wharf project
RE: Unconsolidated gravels, cobbles, boulders - Coastal Wharf project
Bottom line, define first your geotechnical constraints and then plan for the type of step.