TY - THES

T1 - Correlations and empirical relations between static and dynamic elastic ground parameters in shallow geotechnical site investigations

AU - Pölzl, Harald

N1 - embargoed until null

PY - 2012

Y1 - 2012

N2 - Determination of parameters like Young’s Modulus, Shear Modulus and Bulk Modulus is integral part of any geotechnical site investigation. On the one hand well established, but mostly cost and time intensive static methods offer point measurements of moduli over a broad stress and strain range. On the other hand dynamic methods provide measurements of acoustic wave velocities in larger volumes at an arguable amount of time and money that can be easily linked to very small strain dynamic moduli via density. Making use of the advantages and trying to overcome the disadvantages of each approach a method for the derivation of power law empirical relations is presented to estimate static moduli from dynamic moduli with an improved accuracy compared to conventional linear approaches. The available data involves static unconfined compression, triaxial and dilatometer tests and dynamic methods like the spectral analysis of surface waves, downhole seismics, full waveform sonic logging, crosshole seismics and ultrasonic velocity measurements in laboratory performed in carbonatic, siliciclastic, metamorphic and plutonic rocks. Beside the estimation of static moduli a not very successful attempt of estimating UCS from acoustic velocities only is presented. To increase accuracy of UCS estimation velocity, porosity and stress rate are considered additionally, leading to an excellent linear relation between for UCS.

AB - Determination of parameters like Young’s Modulus, Shear Modulus and Bulk Modulus is integral part of any geotechnical site investigation. On the one hand well established, but mostly cost and time intensive static methods offer point measurements of moduli over a broad stress and strain range. On the other hand dynamic methods provide measurements of acoustic wave velocities in larger volumes at an arguable amount of time and money that can be easily linked to very small strain dynamic moduli via density. Making use of the advantages and trying to overcome the disadvantages of each approach a method for the derivation of power law empirical relations is presented to estimate static moduli from dynamic moduli with an improved accuracy compared to conventional linear approaches. The available data involves static unconfined compression, triaxial and dilatometer tests and dynamic methods like the spectral analysis of surface waves, downhole seismics, full waveform sonic logging, crosshole seismics and ultrasonic velocity measurements in laboratory performed in carbonatic, siliciclastic, metamorphic and plutonic rocks. Beside the estimation of static moduli a not very successful attempt of estimating UCS from acoustic velocities only is presented. To increase accuracy of UCS estimation velocity, porosity and stress rate are considered additionally, leading to an excellent linear relation between for UCS.

KW - Statischer Modul

KW - dynamischer Modul

KW - empirische Gleichungen

KW - Geotechnik

KW - static modulus

KW - dynamic modulus

KW - empirical equations

KW - geophysical site investigation

M3 - Master's Thesis

ER -