Evaluation of SCPT-surveys as method for accessing dynamic modulus
The purpose of this master thesis is to evaluate the results from the completed SCPT (Seismic Cone Penetration Test) surveys with respect to the methods ability to estimate dynamic young´s modulus. This has been done by comparing the result from SCPT to other seismic methods and dynamic parameters c...
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Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser
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ndltd-UPSALLA1-oai-DiVA.org-ltu-687562018-06-01T06:12:55ZEvaluation of SCPT-surveys as method for accessing dynamic modulusengGranskär, JoakimLuleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser2018SCPTDynamic modulusSeismic surveysGeotechnical EngineeringGeoteknikThe purpose of this master thesis is to evaluate the results from the completed SCPT (Seismic Cone Penetration Test) surveys with respect to the methods ability to estimate dynamic young´s modulus. This has been done by comparing the result from SCPT to other seismic methods and dynamic parameters converted from “static” geotechnical surveys. SCPT is a relatively new method which has not been used by Sweco or in Sweden to any greater extent and is therefore of interest to be looked in to. By adding two geophones to an ordinary CPT (Cone Penetration Test) equipment as well as including strike plates, hammer and logger system one can log dynamic parameters in addition to the regular parameters logged by a CPT system. This is done by stopping the otherwise continuous CPT survey every meter and striking the strike plates, which are placed under the tracks of the drilling rig. Seismic waves will then travel through the soil down to the geophones and be used to calculate dynamic parameters. For this master thesis a total of 47 geotechnical and geophysical surveys have been considered. The location of these 47 are approximately 7 km north of Norrköping and have been conducted between the years 2016-2017 for the East Link Project. The geotechnical surveys are composed of weight-sounding, ram-sounding and CPT while the geophysical ones are SCPT, refraction-survey and MASW (Multichannel Analysis of Surface Waves). Static elastic parameters have been calculated using the geotechnical survey results according to the Swedish transportation administrations standardized methods. These have then been converted to dynamic parameters with the help of different relationships. When these have been converted they can be compared to SCPT results and other seismic survey methods which also use wave velocity, Poisson’s ratio and density to calculate dynamic elastic parameters. Based on the results from this thesis it can be concluded that the seismic test add-on to a standard CPTu survey is a good method for accessing dynamic modules and it gives extended information of the soil stratigraphy from one single survey point. After the studies and analyses conducted for this thesis it can be concluded that the proposed conversion between static and dynamic young’s modulus using the Alpan curve gives slightly higher values than the ones derived directly from shear waves using SCPT. The other conversion using cone tip resistance to shear wave velocity gives on the other hand slightly lower values than the ones measured with the SCPT. The analysis also indicate similar trends in results between the different seismic methods. These results does however also shows that the used assumptions are somewhat general for accurate comparisons between the methods. Student thesisinfo:eu-repo/semantics/bachelorThesistexthttp://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-68756application/pdfinfo:eu-repo/semantics/openAccess |
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English |
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Others
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SCPT Dynamic modulus Seismic surveys Geotechnical Engineering Geoteknik |
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SCPT Dynamic modulus Seismic surveys Geotechnical Engineering Geoteknik Granskär, Joakim Evaluation of SCPT-surveys as method for accessing dynamic modulus |
description |
The purpose of this master thesis is to evaluate the results from the completed SCPT (Seismic Cone Penetration Test) surveys with respect to the methods ability to estimate dynamic young´s modulus. This has been done by comparing the result from SCPT to other seismic methods and dynamic parameters converted from “static” geotechnical surveys. SCPT is a relatively new method which has not been used by Sweco or in Sweden to any greater extent and is therefore of interest to be looked in to. By adding two geophones to an ordinary CPT (Cone Penetration Test) equipment as well as including strike plates, hammer and logger system one can log dynamic parameters in addition to the regular parameters logged by a CPT system. This is done by stopping the otherwise continuous CPT survey every meter and striking the strike plates, which are placed under the tracks of the drilling rig. Seismic waves will then travel through the soil down to the geophones and be used to calculate dynamic parameters. For this master thesis a total of 47 geotechnical and geophysical surveys have been considered. The location of these 47 are approximately 7 km north of Norrköping and have been conducted between the years 2016-2017 for the East Link Project. The geotechnical surveys are composed of weight-sounding, ram-sounding and CPT while the geophysical ones are SCPT, refraction-survey and MASW (Multichannel Analysis of Surface Waves). Static elastic parameters have been calculated using the geotechnical survey results according to the Swedish transportation administrations standardized methods. These have then been converted to dynamic parameters with the help of different relationships. When these have been converted they can be compared to SCPT results and other seismic survey methods which also use wave velocity, Poisson’s ratio and density to calculate dynamic elastic parameters. Based on the results from this thesis it can be concluded that the seismic test add-on to a standard CPTu survey is a good method for accessing dynamic modules and it gives extended information of the soil stratigraphy from one single survey point. After the studies and analyses conducted for this thesis it can be concluded that the proposed conversion between static and dynamic young’s modulus using the Alpan curve gives slightly higher values than the ones derived directly from shear waves using SCPT. The other conversion using cone tip resistance to shear wave velocity gives on the other hand slightly lower values than the ones measured with the SCPT. The analysis also indicate similar trends in results between the different seismic methods. These results does however also shows that the used assumptions are somewhat general for accurate comparisons between the methods. |
author |
Granskär, Joakim |
author_facet |
Granskär, Joakim |
author_sort |
Granskär, Joakim |
title |
Evaluation of SCPT-surveys as method for accessing dynamic modulus |
title_short |
Evaluation of SCPT-surveys as method for accessing dynamic modulus |
title_full |
Evaluation of SCPT-surveys as method for accessing dynamic modulus |
title_fullStr |
Evaluation of SCPT-surveys as method for accessing dynamic modulus |
title_full_unstemmed |
Evaluation of SCPT-surveys as method for accessing dynamic modulus |
title_sort |
evaluation of scpt-surveys as method for accessing dynamic modulus |
publisher |
Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser |
publishDate |
2018 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-68756 |
work_keys_str_mv |
AT granskarjoakim evaluationofscptsurveysasmethodforaccessingdynamicmodulus |
_version_ |
1718690937939427328 |