Comparison of Standard Penetration Test (SPT) N-value with Alternative Field Test Methods in Determining Moduli for Settlement Predictions

In the determination of immediate settlements, the stiffness of the soil is a critical parameter. The selected value of the modulus of elasticity is typically obtained from published correlations using blow counts from standard penetration tests and tip or skin friction resistances from cone penetration tests. Other methods include the use of dilatometer, pressuremeter, and geophysical seismic tests. Numerous correlations can be used to calculate the modulus of elasticity of the soil. Due to the uncertainty in obtaining adequate elastic moduli for designs, engineers typically use conservative approaches to mitigate risks. Lack of knowledge of the most appropriate field test method and correlation to obtain accurate moduli causes the engineer typically to assign a conservative value, which often leads to overpredictions of ground surface settlements. A comprehensive evaluation of the methods used to determine the modulus of elasticity and calculate immediate settlements is necessary for the granular soil conditions in Florida. At a site at the University of Central Florida, full-scale tests were conducted to measure immediate settlements in a soil profile typical of Florida granular soil conditions. Three conical load tests and a comprehensive laboratory testing program were conducted, and the results are presented to understand the main variables involved in the geotechnical mechanisms that govern immediate settlements in Florida. Numerical finite element analyses were also conducted to provide guidance for researchers and practitioners on an alternative way of calculating immediate settlements using two constitutive models: hardening soil and hardening soil small, which can be easily calibrated from correlations with relative density of granular soil materials. The numerical model results matched well the measured values from conical load tests presented in this research.

Language

  • English

Media Info

  • Media Type: Digital/other
  • Edition: Draft Final Report
  • Features: Appendices; Figures; Photos; References; Tables;
  • Pagination: 263p

Subject/Index Terms

Filing Info

  • Accession Number: 01766053
  • Record Type: Publication
  • Contract Numbers: BDV24-977-29
  • Files: TRIS, ATRI, STATEDOT
  • Created Date: Feb 9 2021 4:06PM