Drained and undrained shear strength of clay for shoring design
Drained and undrained shear strength of clay for shoring design
(OP)
Dear all,
Why undrained strengths (or total stress approaches) instead of drained strengths (or effective stress approaches)are adopted in shoring design in CLAY?
How does drained and undrained shear strength of clay affect the design of temporary or permanent sheetpile? which type of parameter is to be used for the design?
I think undrained parameters of the CLAY are used to assess the short term stability, and it does not imply that the long term stability is satisfactory. Therefore, effective parameters of the CLAY are also needed to determine for assessing the long term stability of the shoring.
Thx.
Why undrained strengths (or total stress approaches) instead of drained strengths (or effective stress approaches)are adopted in shoring design in CLAY?
How does drained and undrained shear strength of clay affect the design of temporary or permanent sheetpile? which type of parameter is to be used for the design?
I think undrained parameters of the CLAY are used to assess the short term stability, and it does not imply that the long term stability is satisfactory. Therefore, effective parameters of the CLAY are also needed to determine for assessing the long term stability of the shoring.
Thx.





RE: Drained and undrained shear strength of clay for shoring design
RE: Drained and undrained shear strength of clay for shoring design
Yes, I agree with u.
For N.C. clay, positive pore water pressure will built up during shearing and short term effect for the design is more critical. But, suction in O.C. clay will dissipate with time and long term effect controls the design.
My next question is:
If loading history of the site is not known, any in-situ testings or laboratary testings can be assigned to determine the OCR of the soil?
RE: Drained and undrained shear strength of clay for shoring design
RE: Drained and undrained shear strength of clay for shoring design
RE: Drained and undrained shear strength of clay for shoring design
Would u pls tell me the details and the reference of the emperical relationship as u suggested.
I know there is a correlation between the ratio of undrained shear strength of N.C. clay (cu) and effective vertical stress (v') to plasticity index (Ip)as proposed by Skempton.
Cu/v' = 0.11 + 0.0037Ip
But, I wonder the above equation can be used to determine OCR?
RE: Drained and undrained shear strength of clay for shoring design