Variation of CPTu-based transformation models for undrained shear strength of Finnish clays

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Variation of CPTu-based transformation models for undrained shear strength of Finnish clays. / Knuuti, Mika ; Länsivaara, Tim.

In: Georisk, Vol. 13, No. 4, 02.10.2019, p. 262-270.

Research output: Contribution to journal › Article › Scientific › peer-review

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@article{e30bbae3eae64cafb44155f8894b5c93,

title = "Variation of CPTu-based transformation models for undrained shear strength of Finnish clays",

abstract = "The determination of a design soil property may include multiple sources of uncertainty. One of the sources originates from transformation model used to evaluate soil parameters when they are not measured directly. This study focuses on the transformation uncertainty related to three different transformation models used in evaluation of undrained shear strength from CPTu borings. The used correlation models are common models found in literature and calibrated at Tampere University. The CPTu data used in this study was taken from Knuuti and L{\"a}nsivaara [2019. Variation of Measured CPTu Data. ISGSR], and it consisted of four different soft clay sites in Finland. The transformation uncertainty was calculated for each transformation model at each site. Moreover, every CPTu boring was analysed separately. The results showed that the transformation uncertainty was lowest for models based on the net cone resistance (COV = 0.033–0.084) and pore pressure (COV = 0.024–0.085). For the third model, the uncertainty was little higher as it included more uncertainty in the initial parameters. This suggests that the transformation models based on net cone resistanse (qNET) and pore pressure (u2) could be more suitable for practice.",

keywords = "coefficient of variation, correlation models, CPTu, reliability, statistics, undrained shear strength",

author = "Mika Knuuti and Tim L{\"a}nsivaara",

year = "2019",

month = "10",

day = "2",

doi = "10.1080/17499518.2019.1644525",

language = "English",

volume = "13",

pages = "262--270",

journal = "Georisk",

issn = "1749-9518",

publisher = "Taylor and Francis Ltd.",

number = "4",

}

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TY - JOUR

T1 - Variation of CPTu-based transformation models for undrained shear strength of Finnish clays

AU - Knuuti, Mika

AU - Länsivaara, Tim

PY - 2019/10/2

Y1 - 2019/10/2

N2 - The determination of a design soil property may include multiple sources of uncertainty. One of the sources originates from transformation model used to evaluate soil parameters when they are not measured directly. This study focuses on the transformation uncertainty related to three different transformation models used in evaluation of undrained shear strength from CPTu borings. The used correlation models are common models found in literature and calibrated at Tampere University. The CPTu data used in this study was taken from Knuuti and Länsivaara [2019. Variation of Measured CPTu Data. ISGSR], and it consisted of four different soft clay sites in Finland. The transformation uncertainty was calculated for each transformation model at each site. Moreover, every CPTu boring was analysed separately. The results showed that the transformation uncertainty was lowest for models based on the net cone resistance (COV = 0.033–0.084) and pore pressure (COV = 0.024–0.085). For the third model, the uncertainty was little higher as it included more uncertainty in the initial parameters. This suggests that the transformation models based on net cone resistanse (qNET) and pore pressure (u2) could be more suitable for practice.

AB - The determination of a design soil property may include multiple sources of uncertainty. One of the sources originates from transformation model used to evaluate soil parameters when they are not measured directly. This study focuses on the transformation uncertainty related to three different transformation models used in evaluation of undrained shear strength from CPTu borings. The used correlation models are common models found in literature and calibrated at Tampere University. The CPTu data used in this study was taken from Knuuti and Länsivaara [2019. Variation of Measured CPTu Data. ISGSR], and it consisted of four different soft clay sites in Finland. The transformation uncertainty was calculated for each transformation model at each site. Moreover, every CPTu boring was analysed separately. The results showed that the transformation uncertainty was lowest for models based on the net cone resistance (COV = 0.033–0.084) and pore pressure (COV = 0.024–0.085). For the third model, the uncertainty was little higher as it included more uncertainty in the initial parameters. This suggests that the transformation models based on net cone resistanse (qNET) and pore pressure (u2) could be more suitable for practice.

KW - coefficient of variation

KW - correlation models

KW - CPTu

KW - reliability

KW - statistics

KW - undrained shear strength

U2 - 10.1080/17499518.2019.1644525

DO - 10.1080/17499518.2019.1644525

M3 - Article

VL - 13

SP - 262

EP - 270

JO - Georisk

JF - Georisk

SN - 1749-9518

IS - 4

ER -

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