ODEX System and soil disturbance
ODEX System and soil disturbance
(OP)
For those who are familiar with the ODEX-type drilling system, is there any infomation regarding the amount of soil disturbance it causes and relation to blow counts? We just recently used this system for the first time in an alluvial area containing poorly graded sands and gravels. The drillers claim there is no soil disturbance caused by the downhole hammer but there is obviously some level of disturbance.





RE: ODEX System and soil disturbance
RE: ODEX System and soil disturbance
RE: ODEX System and soil disturbance
If you are below the water table and need a precise blowcount (for liquefaction assessment for example), insist on water or mud.
RE: ODEX System and soil disturbance
On this job that we used the ODEX, we had tried to use rotary wash but the soil was so gravelly and had so little supporting matrix that even the mud couldn't hold it up and was caving the hole...and this was all happening even before we hit the ground water. We didn't want to use hollow-stem due to heaving issues (although it sounds like ODEX isn't any better with heaving). Our blowcounts were reasonable though for the type of material we were in so it's hard to say how much effect the jetting air/pounding/heaving really had on blow counts. Ideally it would be nice to punch an ODEX hole right next to a hollow-stem hole and be able to compare the differences in blow counts.
It sounds like in the future we'll avoid using ODEX if possible as the blow counts and sample quality are both in question.
RE: ODEX System and soil disturbance