Excavator mounted SPT hammer

[Energy234]

As far as I'm aware, an excavator mounted hydraulic auto SPT hammer doesn't exist.

Is there any technical reason why something like that wouldn't work in the field? Obviously, it wouldn't be as efficient as a terrier rig, but I'm thinking that application during a wider trial pitting programme could offer benefits and overcome some difficulties in terms of rig availability.

Ultimately, who wouldn't like to have SPT values alongside TP logs?

 

[MTNClimber]

I think there would be a variety of technical difficulties there. From how to pull the sampler after driving to the excavation contractor not taking good care of the SPT equipment. Cheap alternatives would be using a DCP or 3' rebar and 5 lb hammer. Or, just hire a driller to come in after the test pits are completed like every other geotech.

 

[TigerGuy]

I worked with a drilling contractor that had a GeoProbe mounted on a skid steer. It had the auto hammer and all tooling for GeoProbe sampling and SPT/auger drilling. It was a tracked skid steer, so it was much more efficient when you needed the tracked rig, but didn't want to wait for 1.5 mph between borings.

Alternatively, you can always bring the cathead out of retirement.

 

[EireChch]

Just use a DPSH (Dynamic Probe Super Heavy), very commonly used in the UK. Can get rigs which are just two wheels, and can be pushed/manueovered in place by 2 people. Very accessible.

 

[GeoEnvGuy]

An auto hammer works on hydraulics typically so you in theory can attach the SPT hammer on an excavator arm by disconnecting the bucket or adding more hydraulic lines to it. Not sure what hammer efficiency you would get with an odd arrangement. Also what is the thought process for testing are you just doing the top 2 feet because I wouldn't think digging down with the bucket and doing another test after relieving the overburden confining stress over the size of a bucket compared to a drill hole diameter is a good idea.