Using RMR System to Determine Mass Strength of Jet Grout or Concrete
Using RMR System to Determine Mass Strength of Jet Grout or Concrete
(OP)
I am wondering if anyone has used the RMR system or Q system to rate or determine the mass strength of anything other than rocks such as unique concretes like soilcrete.
I am trying to apply the RMR or Q system to insitu Jet Grout material. I am having issues as the RMR system is mainly governed by discontinuities within rocks whereas my insitu jet grout material does not have any major discontinuities. Instead, it is full of soil inclusions and voids.
If there are any other ideas on ways to rate and evaluate the mass strength of a large mass (width = 20 m length=6 m depth=25 m) of soilcrete (approx 2 Mpa) underground, I would be very interested to hear them.
Additional Information: The jet grout is being used as a headwall for a tunnel boring machine and its primary function is groundwater cut-off with a secondary function as part of the support of excavation for the exit shaft of the tunnel boring machine.
Thanks!
I am trying to apply the RMR or Q system to insitu Jet Grout material. I am having issues as the RMR system is mainly governed by discontinuities within rocks whereas my insitu jet grout material does not have any major discontinuities. Instead, it is full of soil inclusions and voids.
If there are any other ideas on ways to rate and evaluate the mass strength of a large mass (width = 20 m length=6 m depth=25 m) of soilcrete (approx 2 Mpa) underground, I would be very interested to hear them.
Additional Information: The jet grout is being used as a headwall for a tunnel boring machine and its primary function is groundwater cut-off with a secondary function as part of the support of excavation for the exit shaft of the tunnel boring machine.
Thanks!





RE: Using RMR System to Determine Mass Strength of Jet Grout or Concrete
Richard A. Cornelius, P.E.
WWW.amlinereast.com
RE: Using RMR System to Determine Mass Strength of Jet Grout or Concrete
My main problem is to come up with an ideal way to assess the overall mass strength and integrity of the jet grout. If a test pit is created with test jet grout columns and sequentially excavated to allow mapping of the grout, what rating system would be most applicable to this material. RMR and Q seem difficult to adapt to a soilcrete since they are mostly geared towards rock.
Thank you.
RE: Using RMR System to Determine Mass Strength of Jet Grout or Concrete
The only way to get the strength of your soilcrete is to prepare samples and have them tested (unconfined compression).