An empirical approach to estimate Epmt and Pl of silty clays based on SPT

Akbar Cheshomi, Ehsan Bakhtiyari, Hossein Masoumi

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4 Citations (Scopus)


The use of in-situ soil testing has become popular in many geotechnical projects because of its high measurement accuracy and low disturbance of the soil sample during the testing process. Pressuremeter Test (PMT) and standard penetration test (SPT) are two important in-situ tests in geotechnical engineering. The former is an expensive and time-consuming experiment that can measure some detailed mechanical properties of soil while the latter is low-cost and can estimate some basic soil specifications. Thus, identifying the relationship between PMT and SPT parameters can help improve the mechanical characterization of soil samples through a cost-saving methodology. In this research, 47 SPT and 47 PMT were performed on very stiff and hard silty clay and clay soil samples. The variation range of EPMT and the N60 are in the range of 16.55-75.95 MPa and 16-51, respectively. Empirical equations were proposed between EPMT-N60, PL-N60, and EPMT-PL with R2 ≥ 0.65. Regression analysis by determining ‘R2 ’, ‘Sig.’, and ‘F’ values demonstrated that the proposed models are highly significant and strongly meaningful. The Mean Square Error (MSE) and Root Mean Square Error (RMSE) values for each relation showed that the estimation error is very small, and the relationships are acceptable. The equations proposed in this research can be used for very stiff and hard silty clay and clay soil types. Also, by comparing the N60 and EPMT/PL values, silty clay and clay soil were classified in terms of consistency according to EPMT/PL ratio. Finally, the results from this study were grouped and compared with those reported earlier, leading to a practical advisory methodology for the estimation of PMT parameters from the SPT data applicable to a wide range of soil samples.

Original languageEnglish
Pages (from-to)310-323
Number of pages14
JournalActa Montanistica Slovaca
Issue number3
Publication statusPublished - 2020


  • Limit Pressure
  • PMT
  • Pressuremeter Modulus
  • SPT

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