Methods to mitigate expansion of pyritic shales below slabs

[dschauble]

Project in construction where unforeseen pyritic shale has been encountered beneath a portion of the building. Impacted foundation and utility excavations are being treated with bitumastic seal prior to concrete/utility placement; however, in areas where the pyritic material is present at the building pad subgrade elevation, looking for alternatives. Is there a rule of thumb for minimum depth of remaval and replacement? Should forms which allow for expansion be utilized to "support" the slab-on-grade to allow for long-term potential expansion of the pyritic material? or is that an cost=prohibitive option. Thanks in advance for your assistance.

dschauble
AdvantageEngineers.com

 

[fattdad]

Don't use lime or cement stabilization.

Not sure about undercut requirements.

f-d

¡papá gordo ain’t no madre flaca!