Advancing hand auger probes through caving soil/stone
Advancing hand auger probes through caving soil/stone
(OP)
Our firm does frequent geotechnical investigations utilizing hand auger probings with DCP testing in lieu of other in-situ testing due to project/site constraints. For us, and maybe many of you, some of the constraints of trying to perform a geotechnical investigation within the footprint of an existing structure results are as follows:. Once exposed, the auger probing can be advanced through the subbase and finally, the subgrade can be reached. However, the majority of our problems stem from the type of material used as subbase and the thickness of the subbase. These problems may include:
1. What are some effective ways to remove washed stone from a hand auger probing?
In the past, I've found that using a typical 3" diameter hand auger bucket provides poor to moderate results when the stone thickness is 6 inches or less, and as the stone thickness increases, the results become poor to non-existent. More recently, we've added the use of a wet/dry shop vacuum to are arsenal of hand auger field equipment. The results were more promising given the following:
Are there any hand auger buckets specifically made for washed stone?
Are there any modifications that can be made to readily available hand auger buckets that facilitate use in washed stone?
Any other suggestions are welcome.
2. What are some effective tools used to prevent caving of loose soil/stone in hand auger boring?
Another additional method we've employed has been the use of a standard size 4.0" diameter PVC pipe as a casing for hand auger probings. The casing does what it is intended to do (keep the hole from caving) but it has its drawbacks.
Has anyone used a different method of casing a hand auger probing with success?
Has anyone used a different type of material as a casing with success?
Is there a way to add vibration to the casing to help advance it through washed stone? If not, would using one of these in the washed stone help advance the casing? (Apparently the v-word is picked up on the language filter.)
Any other suggestions are welcome.
Thank you for your time. =)
- Low overhead clearance
- Limited access for drilling/sounding rigs by physical dimension, weight, etc
- Noise
- Cost
- Other reasons
- Caving subbase (such as washed stone)
- Trying to loosen up compacted ABC stone
- Spending too much fighting the aforementioned items
1. What are some effective ways to remove washed stone from a hand auger probing?
In the past, I've found that using a typical 3" diameter hand auger bucket provides poor to moderate results when the stone thickness is 6 inches or less, and as the stone thickness increases, the results become poor to non-existent. More recently, we've added the use of a wet/dry shop vacuum to are arsenal of hand auger field equipment. The results were more promising given the following:
- Your vacuum has good suction power
- Your vacuum hose diameter is large enough to accommodate the size of the aggregate
- The thickness of the stone is less than 2.0 feet or so (the deeper you're trying to remove stone, the more power/airflow you'll need)
Are there any hand auger buckets specifically made for washed stone?
Are there any modifications that can be made to readily available hand auger buckets that facilitate use in washed stone?
Any other suggestions are welcome.
2. What are some effective tools used to prevent caving of loose soil/stone in hand auger boring?
Another additional method we've employed has been the use of a standard size 4.0" diameter PVC pipe as a casing for hand auger probings. The casing does what it is intended to do (keep the hole from caving) but it has its drawbacks.
- PVC is weak and can damage if abused
- A 6.0" diameter core is needed to fit the 4.5" outer-diameter casing
- The casing and hand auger cannot be advanced simultaneously
- The when retracting the hand auger from the casing, the friction between the hand auger, casing, and washed stone will pull the casing out of the hole
Has anyone used a different method of casing a hand auger probing with success?
Has anyone used a different type of material as a casing with success?
Is there a way to add vibration to the casing to help advance it through washed stone? If not, would using one of these in the washed stone help advance the casing? (Apparently the v-word is picked up on the language filter.)
Any other suggestions are welcome.
Thank you for your time. =)
RE: Advancing hand auger probes through caving soil/stone
To the rest of your post, yes all the things you mention can and do happen.
f-d
¡papá gordo ain’t no madre flaca!
RE: Advancing hand auger probes through caving soil/stone
RE: Advancing hand auger probes through caving soil/stone
I guess it's judging collateral damages and such.
f-d
¡papá gordo ain’t no madre flaca!
RE: Advancing hand auger probes through caving soil/stone
let me know if it works out for you.
RE: Advancing hand auger probes through caving soil/stone
I found air heating duct pipes of aluminum to be just too weak to do the job.