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Priyantha W. Jayawickrama - One of the best experts on this subject based on the ideXlab platform.

  • Side-by-Side Correlation of Texas Cone Penetration and Standard Penetration Test Blowcount Values
    Geotechnical and Geological Engineering, 2018
    Co-Authors: William D. Lawson, Earnest O. Terrell, James G. Surles, Rozbeh B. Moghaddam, Hoyoung Seo, Priyantha W. Jayawickrama
    Abstract:

    This paper presents side-by-side comparisons of blowcount values for the Texas cone Penetration (TCP) Test and the Standard Penetration Test (SPT). The comparisons yielded statistically-significant regression models for both coarse-grained soils and fine-grained soils. Consistent with expected trends and published data, the TCP–SPT relationship is nonlinear, with weak to fair correlation strength ( R ^ 2  = 23–44%). For TCP blowcounts ( N _ 60, TCP ) varying from 25 to 200 blows/30 cm (1 ft), corresponding SPT blowcounts ( N _ 60, SPT ) are typically 30–60% lower than N _ 60, TCP in fine-grained soils. Likewise, corresponding N _ 60, SPT blowcounts are 10–70% lower than N _ 60, TCP in coarse-grained soils, all other things being equal. Comparative data were obtained from published sources and from project-specific field research sites used for full-scale deep foundation load Tests. The final dataset consisted of 225 Test pairs obtained in similar soils and geomaterials, at equivalent depths, with all blowcounts normalized to 30 cm (12 in.) Penetration (i.e., blows/30 cm or blows/ft) within the bounds of typical Test precision, and corrected to 60% hammer efficiency. The generally weak correlations do not support conversion of N _ 60, TCP to N _ 60, SPT (or vice versa) to compute foundation capacity for final design. But, engineers can certainly get an intuitive feel about site conditions and preliminary foundation capacity by using the correlation equations to translate their knowledge of one Test to the other. This study extends previous work by formally comparing and contrasting the similar yet different SPT and TCP Test methods in such a way as to make the results useful to users of both Tests and to the broader geotechnical engineering community.

William D. Lawson - One of the best experts on this subject based on the ideXlab platform.

  • Side-by-Side Correlation of Texas Cone Penetration and Standard Penetration Test Blowcount Values
    Geotechnical and Geological Engineering, 2018
    Co-Authors: William D. Lawson, Earnest O. Terrell, James G. Surles, Rozbeh B. Moghaddam, Hoyoung Seo, Priyantha W. Jayawickrama
    Abstract:

    This paper presents side-by-side comparisons of blowcount values for the Texas cone Penetration (TCP) Test and the Standard Penetration Test (SPT). The comparisons yielded statistically-significant regression models for both coarse-grained soils and fine-grained soils. Consistent with expected trends and published data, the TCP–SPT relationship is nonlinear, with weak to fair correlation strength ( R ^ 2  = 23–44%). For TCP blowcounts ( N _ 60, TCP ) varying from 25 to 200 blows/30 cm (1 ft), corresponding SPT blowcounts ( N _ 60, SPT ) are typically 30–60% lower than N _ 60, TCP in fine-grained soils. Likewise, corresponding N _ 60, SPT blowcounts are 10–70% lower than N _ 60, TCP in coarse-grained soils, all other things being equal. Comparative data were obtained from published sources and from project-specific field research sites used for full-scale deep foundation load Tests. The final dataset consisted of 225 Test pairs obtained in similar soils and geomaterials, at equivalent depths, with all blowcounts normalized to 30 cm (12 in.) Penetration (i.e., blows/30 cm or blows/ft) within the bounds of typical Test precision, and corrected to 60% hammer efficiency. The generally weak correlations do not support conversion of N _ 60, TCP to N _ 60, SPT (or vice versa) to compute foundation capacity for final design. But, engineers can certainly get an intuitive feel about site conditions and preliminary foundation capacity by using the correlation equations to translate their knowledge of one Test to the other. This study extends previous work by formally comparing and contrasting the similar yet different SPT and TCP Test methods in such a way as to make the results useful to users of both Tests and to the broader geotechnical engineering community.

Chris R Daniel - One of the best experts on this subject based on the ideXlab platform.

  • energy transfer and grain size effects during the Standard Penetration Test spt and large Penetration Test lpt
    2008
    Co-Authors: Chris R Daniel
    Abstract:

    The Standard Penetration Test (SPT) is the most widely used in-situ soil Test in the world. "Large Penetration Test" (LPT) is a term used to describe any scaled up version of the SPT. Several types of LPT have been developed around the world for the purpose of characterizing gravel deposits, as SPT blow counts are less reliable in gravels than in sands. Both Tests suffer from the lack of a reliable means of determining transferred energy. Further, the use of LPT blow counts is generally limited to calculation of equivalent SPT blow counts using correlation factors measured in sands. Variation of LPT blow counts with grain size is assumed to be negligible. This research shows that safety hammer energies can be reliably estimated from measurements of hammer impact velocity for both SPT and LPT. This approach to determining transferred energy is relatively simple, and avoids the primary limitation of existing methods, which is the inability to calibrate the instrumentation. Transferred energies and hammer impact velocities are collected from various sources. These data are used to determine the ratio between the hammer kinetic energy and the transferred energy (energy transfer ratio, ETR), which is found to follow a roughly Normal distribution for the various hammers represented. An assessment of uncertainty is used to demonstrate that an ETR based approach could be superior to existing energy measurement methods. SPT grain size effects have primarily been characterized as the variation of an empirical relative density correlation factor, (CD)SPT, with mean grain size. In this thesis, equivalent (CD)LPT data are back-calculated from measured SPT-LPT correlation factors (CS/L). Results of a numerical study suggest that SPT and LPT grain size effects should be similar and related to the ratio of the sample size to the mean grain size. Based on this observation, trend-lines with the same shape as the (CD)SPT trend-line are established for the back-calculated (CD)LPT data. A method for generating the grain size effect trend-line for LPT is then proposed. These trend lines provide a rational approach to direct interpretation of LPT data, or to improved prediction of equivalent SPT blow counts.

  • Discussion of “Review of Standard Penetration Test Short Rod Corrections” by Chris R. Daniel, John A. Howie, R. Scott Jackson, and Brian Walker
    Journal of Geotechnical and Geoenvironmental Engineering, 2006
    Co-Authors: Chris R Daniel, John A. Howie, R. Scott Jackson, Brian Walker
    Abstract:

    The authors are to be commended for bringing up the matter of whether or not to correct the NSPT values for rods shorter than 10.0 m. The Standard Penetration Test SPT International Reference Test Procedure IRTP Decourt et al. 1988 has been mentioned in this paper; and the discusser, as one of the authors of that document, would like to offer additional information on this matter. First, the document mentioned in the paper was not actually the official SPT International Reference Test Procedure. Rather, it was just a preview of the official document that the Swedish Geotechnical Society published one year later, during the 12th International Conference of Soil Mechanics and Foundation Engineering, held in Rio de Janeiro in 1989. The former document presented an analysis of energy measurements that was based on the pioneer work by Schmertmann and Palacios 1979 ; and, as mentioned by the authors, used the F2 method. Schmertmann, by the way, was also one of the authors of the IRTP. Nevertheless, within the committee that elaborated the IRTP, no consensus existed about the adequacy of this method

  • Discussion of "Review of Standard Penetration Test Short Rod Corrections"
    2006
    Co-Authors: Chris R Daniel, John A. Howie, R. Scott Jackson, Brian Walker
    Abstract:

    values for rods shorter than10.0 m.The Standard Penetration Test SPT International ReferenceTest Procedure IRTP Decourt et al. 1988 has been mentionedin this paper; and the discusser, as one of the authors of thatdocument, would like to offer additional information on thismatter.First, the document mentioned in the paper was not actuallythe official SPT International Reference Test Procedure. Rather, itwas just a preview of the official document that the SwedishGeotechnical Society published one year later, during the 12thInternational Conference of Soil Mechanics and FoundationEngineering, held in Rio de Janeiro in 1989.The former document presented an analysis of energy mea-surements that was based on the pioneer work by Schmertmannand Palacios 1979 ; and, as mentioned by the authors, used the

  • Review of Standard Penetration Test short rod corrections
    Journal of Geotechnical and Geoenvironmental Engineering, 2005
    Co-Authors: Chris R Daniel, John A. Howie, R. Scott Jackson, Brian Walker
    Abstract:

    Short rod corrections are used to reduce Standard Penetration Test blow counts recorded using rod lengths shorter than 10 m to values that would have been recorded if longer rods had been used. They are based on the assumption that energy transferred during secondary impacts does not contribute to sampler Penetration. This paper describes modifications made to a safety hammer to provide hammer–anvil contact histories. Data collected demonstrate the occurrence of secondary impacts prior to the time at which the hammer and anvil were originally assumed to separate. These impacts can be predicted given only the dimensions of the hammer and rods. Secondary impacts are also observed after this time and the energy transferred is quantified. The data suggest that the total transferred energy is independent of rod length and that the secondary impacts occur early enough to contribute to sampler Penetration. Modified short rod corrections may still be justified if transferring energy over a series of impacts leads...

  • a method for correlating large Penetration Test lpt to Standard Penetration Test spt blow counts
    Canadian Geotechnical Journal, 2003
    Co-Authors: Chris R Daniel, John A. Howie, A. Sy
    Abstract:

    The Standard Penetration Test (SPT) split-spoon sampler is too small for investigations in gravelly soils. For this reason, several researchers have developed scaled-up versions of the SPT, commonl...

Earnest O. Terrell - One of the best experts on this subject based on the ideXlab platform.

  • Side-by-Side Correlation of Texas Cone Penetration and Standard Penetration Test Blowcount Values
    Geotechnical and Geological Engineering, 2018
    Co-Authors: William D. Lawson, Earnest O. Terrell, James G. Surles, Rozbeh B. Moghaddam, Hoyoung Seo, Priyantha W. Jayawickrama
    Abstract:

    This paper presents side-by-side comparisons of blowcount values for the Texas cone Penetration (TCP) Test and the Standard Penetration Test (SPT). The comparisons yielded statistically-significant regression models for both coarse-grained soils and fine-grained soils. Consistent with expected trends and published data, the TCP–SPT relationship is nonlinear, with weak to fair correlation strength ( R ^ 2  = 23–44%). For TCP blowcounts ( N _ 60, TCP ) varying from 25 to 200 blows/30 cm (1 ft), corresponding SPT blowcounts ( N _ 60, SPT ) are typically 30–60% lower than N _ 60, TCP in fine-grained soils. Likewise, corresponding N _ 60, SPT blowcounts are 10–70% lower than N _ 60, TCP in coarse-grained soils, all other things being equal. Comparative data were obtained from published sources and from project-specific field research sites used for full-scale deep foundation load Tests. The final dataset consisted of 225 Test pairs obtained in similar soils and geomaterials, at equivalent depths, with all blowcounts normalized to 30 cm (12 in.) Penetration (i.e., blows/30 cm or blows/ft) within the bounds of typical Test precision, and corrected to 60% hammer efficiency. The generally weak correlations do not support conversion of N _ 60, TCP to N _ 60, SPT (or vice versa) to compute foundation capacity for final design. But, engineers can certainly get an intuitive feel about site conditions and preliminary foundation capacity by using the correlation equations to translate their knowledge of one Test to the other. This study extends previous work by formally comparing and contrasting the similar yet different SPT and TCP Test methods in such a way as to make the results useful to users of both Tests and to the broader geotechnical engineering community.

James G. Surles - One of the best experts on this subject based on the ideXlab platform.

  • Side-by-Side Correlation of Texas Cone Penetration and Standard Penetration Test Blowcount Values
    Geotechnical and Geological Engineering, 2018
    Co-Authors: William D. Lawson, Earnest O. Terrell, James G. Surles, Rozbeh B. Moghaddam, Hoyoung Seo, Priyantha W. Jayawickrama
    Abstract:

    This paper presents side-by-side comparisons of blowcount values for the Texas cone Penetration (TCP) Test and the Standard Penetration Test (SPT). The comparisons yielded statistically-significant regression models for both coarse-grained soils and fine-grained soils. Consistent with expected trends and published data, the TCP–SPT relationship is nonlinear, with weak to fair correlation strength ( R ^ 2  = 23–44%). For TCP blowcounts ( N _ 60, TCP ) varying from 25 to 200 blows/30 cm (1 ft), corresponding SPT blowcounts ( N _ 60, SPT ) are typically 30–60% lower than N _ 60, TCP in fine-grained soils. Likewise, corresponding N _ 60, SPT blowcounts are 10–70% lower than N _ 60, TCP in coarse-grained soils, all other things being equal. Comparative data were obtained from published sources and from project-specific field research sites used for full-scale deep foundation load Tests. The final dataset consisted of 225 Test pairs obtained in similar soils and geomaterials, at equivalent depths, with all blowcounts normalized to 30 cm (12 in.) Penetration (i.e., blows/30 cm or blows/ft) within the bounds of typical Test precision, and corrected to 60% hammer efficiency. The generally weak correlations do not support conversion of N _ 60, TCP to N _ 60, SPT (or vice versa) to compute foundation capacity for final design. But, engineers can certainly get an intuitive feel about site conditions and preliminary foundation capacity by using the correlation equations to translate their knowledge of one Test to the other. This study extends previous work by formally comparing and contrasting the similar yet different SPT and TCP Test methods in such a way as to make the results useful to users of both Tests and to the broader geotechnical engineering community.