This study investigated the effects of tube sampling disturbances on undrained shear characteristics of reconstituted samples of three coastal soils. The values of undrained shear strength (s sub u) and initial tangent modulus (E sub i) were reduced, whereas axial strain at peak deviator stress (epsilon sub p) increased because of a disturbance caused by penetration of samplers. Disturbances also reduced initial effective stress (sigma' sub i) and pore pressure changes considerably. The changes in soil parameters between the "in situ" and "tube" samples depended markedly on the geometry of samplers used to retrieve tube samples. Values of s sub u, E sub i, and sigma' sub i of samples were reduced, whereas the values of epsilon sub p increased with an increasing area ratio (or decreasing external diameter to thickness ratio) and an increasing outside cutting edge angle of the samplers. Different reconsolidation procedures were adopted to assess the suitability of reconsolidation of tube samples to recover in situ properties. It was found that the coefficient of earth pressure at rest-reconsolidation of tube samples to vertical effective stresses equal to 1.5 and 2.5 times the in situ vertical effective stress produced the best overall estimate of in situ characteristics.


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  • Accession Number: 00798319
  • Record Type: Publication
  • Contract Numbers: NAS8-38779, MSM 8858001
  • Files: TRIS
  • Created Date: Aug 31 2000 12:00AM