IN-SITU AND LABORATORY SHEAR VELOCITY AND MODULUS

Field and laboratory shear wave velocity and shear modulus data are presented and compared. Field tests included down-hole and large-strain cross-hole geophysical methods while laboratory tests included resonant column and cyclic and static triaxial tests. The low-strain velocity values measured by two field testing methods (down-hole and cross-hole) were in reasonably good agreement but the low-strain data from laboratory resonant column tests were approximately 50 percent lower than the corresponding field values. The modulus reduction data (G/G sub max) from field cross-hole tests in general fell between the Seed-Idriss sand and clay reduction curves. Based on the data presented herein and elsewhere, obtaining the maximum shear modulus based on shear strength should be used with caution, if at all. The low-strain velocity in the field for most soils may be estimated approximately by multiplying the velocity value obtained from laboratory cyclic triaxial tests at 0.1 percent strain by an empirically determined value of 2.3. The field shear wave velocity may be higher than the laboratory determined shear wave velocity by about 100 percent at low strain and by about 25 percent at high strain. These differences were probably caused by disturbance and differences in boundary conditions. Finally, obtaining modulus reduction curves by combining field test data and laboratory test data may result in a significant error. /Author/

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 198-212

Subject/Index Terms

Filing Info

  • Accession Number: 00179747
  • Record Type: Publication
  • Report/Paper Numbers: Proceeding
  • Files: TRIS
  • Created Date: Oct 12 1978 12:00AM