JILesarri
Geotechnical
- Sep 14, 2011
- 1
I am designing a 40 feet drilled shaft wall in DFW located in Eagle Ford shale.
There are some contradictions between some designs I have seen and it is not clear what long term strength parameters I should use as well as whether or not the apparent earth pressure diagram that all the publications provide is applicable in this case.
Additionally none clearly resolves my concerns about the hydrostatic pressure in this almost impervious formation as well as whether or not to consider the initial stresses in the ground due to its history.
The earth pressure diagrams I am receiving are based on an apparent trapezoid plus hydrostatic pressure. Ko gets dissipated once the drilled shafts are installed and the ground deforms outwards.
Effecive cohesion is neglected. Direct shear tests result in a fi=30 deg and c'=300psf (peak).
I have seen short term cuts in Gran Praire up to 40 feet standing up easily although also heard horrible histories about the shale when fails.
Any help with similar experience will be highly appreciated.
There are some contradictions between some designs I have seen and it is not clear what long term strength parameters I should use as well as whether or not the apparent earth pressure diagram that all the publications provide is applicable in this case.
Additionally none clearly resolves my concerns about the hydrostatic pressure in this almost impervious formation as well as whether or not to consider the initial stresses in the ground due to its history.
The earth pressure diagrams I am receiving are based on an apparent trapezoid plus hydrostatic pressure. Ko gets dissipated once the drilled shafts are installed and the ground deforms outwards.
Effecive cohesion is neglected. Direct shear tests result in a fi=30 deg and c'=300psf (peak).
I have seen short term cuts in Gran Praire up to 40 feet standing up easily although also heard horrible histories about the shale when fails.
Any help with similar experience will be highly appreciated.
