Finally someone who explains in concise detail how the whole process of drilling works. The animation really helped me understand all those details that mere filmed material wouldn't. Thank you!
Also hollow flight augers are basically useless in anything but soft soils and for shallow holes. Also no drill rig actually hits the casing into the ground it has to be pushed or drilled into the ground. Almost any drilling capable of drill over 6m will not use hollow aurgers
When the drilling and you have reached the test depth you stop the fluids flowing through the drill head and a hose will attached to the casing whicjmh can constantly fill the hole as the rods are removed
Pls tell me where I can see a drilling rig that uses the rotary mud technique without casing as a normal practice. Can you imagine the amount of drilling fluid you would need if you just pump it out of the hole without retaining it. If a pump can pump around 100L a minute and rotary mud drilling 1.5m time will vary from 1min to 30 minutes so to drill a 50m hole at a rate of 1.5m per 3minutes not including the amount of time it takes to do a test U50 could be up to 10m and an spt could be up to 20minutes so to drill like this I would need an Olympic swimming pool worth of water.
@@danotorioust2867 Not necessarily true geo techs, design various retaining walls. There is slope factors, lateral earth factors, seepage, drainage, determing types of soil is vital information needed for a retaining wall.
Turn the water off and disconnect the hose OMG so when you talk about hydrostatic pressure on the hole wall yes correct but what happens if you turn off the water flow to the hole. Just think about filling your bath up hop in and out what happens to the water level. If you turn the water flow off then remove the drilling rods the hydrostatic pressure will be dramatically reduced causing the walls to actually cave in it's the weight of the drilling fluids that hold the hole open
Split spoon sampler driven by 140# hammer free falling 30" if I remember correctly...you get the sample and penetration data. I ran a geotech rig about thirty years ago.
The SPT is a sampling method that also provides a measure of in situ soil properties (the N value). It can be performed in a cased hole or an uncased hole.
An SPT is a 450mm long hollow tube that is lowered to the bottom of the hole a slide hammer and anvil are attached to the drill rod and 3 measurements of 150mm are marked on the drill rod the engineer counts the hits for each 150mm section the first 150mm is for cave (cuttings still in the hole) and the next two sections hit count is recorded the two numbers add up to make the N value Example test at 24m will read like this on the bore logs 24m spt 8-12-16 N= 28 If the soil resistance is great then 30 hits for the first 150mm the test the test we be terminated and the depth targeted to test
In my experience, percussion drilling is not normally used is soil or rock sampling. This is more commonly use in drilling hard rock for anchor bolts or pile foundations, but not for gathering samples for lab testing. There are other drilling methods which are not covered in the webcast such as sonic drilling (very interesting method). I recently found that air rotary is a common method in West Texas. It's much like mud rotary but uses compressed air rather than drilling mud to bring up the cuttings. I'm sure there are other regional methods I have not encountered.
