The SPT (Standard Penetration Test) is one of the most widely used geotechnical investigations in... more The SPT (Standard Penetration Test) is one of the most widely used geotechnical investigations in the world; the test is usually interpreted with site-specific empirical experimental correlations, that are not physically based; in the author's previous papers [Froldi, 2024, Rational SPT], a procedure based on robust energetic and mechanical principles was illustrated, with which to scientifically and rationally evaluate the test. Very frequently, in coarse or very compacted fine soils, the SPT test is only practicable with the use of the solide steel cone (closed conical tip) with an angle of 60°, whose penetration mechanics are very different from those of the standard sampler; it has been observed that, if not adequately corrected, the result in terms of N SPT leads to large overestimates in the strength parameters obtained from the usual correlations (sampler correlations). This paper compares the mechanics of the closed conical tip versus the standard drive shoe as well as the tip resistance models in granular soils that can be adopted to estimate the friction angle.
The SPT (Standard Penetration Test) is one of the most widely used investigations in the world fo... more The SPT (Standard Penetration Test) is one of the most widely used investigations in the world for the soils geotechnical characterization; in most cases is still interpreted using site-specific experimental empirical correlations but this approach in not physically based and almost always does not consider the boundary conditions of the test (confining pressure, water table, ecc.). In the previous paper, the the main physical-mechanical criteria for a correct and scientific interpretation of the SPT test were established [Froldi, 2024]; the procedure outlined was called "Rational interpretation of the SPT". In this paper, the results of the interpretation of several tests on granular soils and the developments of the described procedure are presented. The discussion is focused on the calibration of the data deduced from the tests, in order to correctly adjust the analytical procedure already described.
The rational interpretation of the SPT (Standard Penetration Test), 2024
The SPT (Standard Penetration Test) is still, since the 1950s, one of the most widely used invest... more The SPT (Standard Penetration Test) is still, since the 1950s, one of the most widely used investigations in the world for the soils geotechnical characterization; in most cases, this soils geotechnical characterization takes place through the use of site-specific experimental empirical correlations. Despite their wide and experienced diffusion, these correlations are not physically based and generally work on the raw parameter N SPT which does not represent a quantity with mechanical meaning; for this reason, the analytical solutions, such as those illustrated in this paper, represent a more effective and reliable method in engineering design practice. Starting from the dynamic analysis of the test, its static equivalence is deduced to determine the resistance characteristics of granular soils.
The SPT (Standard Penetration Test) is one of the most widely used geotechnical investigations in... more The SPT (Standard Penetration Test) is one of the most widely used geotechnical investigations in the world; the test is usually interpreted with site-specific empirical experimental correlations, that are not physically based; in the author's previous papers [Froldi, 2024, Rational SPT], a procedure based on robust energetic and mechanical principles was illustrated, with which to scientifically and rationally evaluate the test. Very frequently, in coarse or very compacted fine soils, the SPT test is only practicable with the use of the solide steel cone (closed conical tip) with an angle of 60°, whose penetration mechanics are very different from those of the standard sampler; it has been observed that, if not adequately corrected, the result in terms of N SPT leads to large overestimates in the strength parameters obtained from the usual correlations (sampler correlations). This paper compares the mechanics of the closed conical tip versus the standard drive shoe as well as the tip resistance models in granular soils that can be adopted to estimate the friction angle.
The SPT (Standard Penetration Test) is one of the most widely used investigations in the world fo... more The SPT (Standard Penetration Test) is one of the most widely used investigations in the world for the soils geotechnical characterization; in most cases is still interpreted using site-specific experimental empirical correlations but this approach in not physically based and almost always does not consider the boundary conditions of the test (confining pressure, water table, ecc.). In the previous paper, the the main physical-mechanical criteria for a correct and scientific interpretation of the SPT test were established [Froldi, 2024]; the procedure outlined was called "Rational interpretation of the SPT". In this paper, the results of the interpretation of several tests on granular soils and the developments of the described procedure are presented. The discussion is focused on the calibration of the data deduced from the tests, in order to correctly adjust the analytical procedure already described.
The rational interpretation of the SPT (Standard Penetration Test), 2024
The SPT (Standard Penetration Test) is still, since the 1950s, one of the most widely used invest... more The SPT (Standard Penetration Test) is still, since the 1950s, one of the most widely used investigations in the world for the soils geotechnical characterization; in most cases, this soils geotechnical characterization takes place through the use of site-specific experimental empirical correlations. Despite their wide and experienced diffusion, these correlations are not physically based and generally work on the raw parameter N SPT which does not represent a quantity with mechanical meaning; for this reason, the analytical solutions, such as those illustrated in this paper, represent a more effective and reliable method in engineering design practice. Starting from the dynamic analysis of the test, its static equivalence is deduced to determine the resistance characteristics of granular soils.
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Papers by piergiuseppe froldi