Location

St. Louis, Missouri

Session Start Date

3-11-1991

Session End Date

3-15-1991

Abstract

In order to determine dynamic parameters to use for seismic microzoning purposes in a new development area near Florence, the dynamic behavior of the alluvial silty clays situated in the upper 60 m of the deposit was experimentally investigated using geophysical surveys and cyclic laboratory tests. Previous studies on the geotechnical properties of the clays of Florence revealed that, in spite of some similarities in a comparison with other coeval clays described in the literature this soil exhibits a few anomalies, as e.g. higher variations between field and laboratory shear waves velocities and remarkable differences in the coefficients of the empirical relations that link the shear modulus to other geotechnical parameters. Moreover, many current correlations from CPT and DMT tests resulted not valid. This peculiar behavior cannot be explained in terms of cementation, because the carbonatic contents values, even if scattered, are practically normal. The objectives of the test program herein described were, therefore, as much to deepen our knowledge of the dynamic behavior of the soil both in situ and in laboratory, at low and high strain level, as to find out the reasons for this different behavior, by examining the possible influence of sample disturbance and of long-term effects, as well as of different geophysical survey techniques. The results of crosshole tests (CH), of spectral analysis of superficial waves surveys (SASW), of resonant column tests (RC) and of triaxial tests with measurement of shear and longitudinal wave velocities (Vt1), as well as the empirical relationships obtained between geotechnical parameters are analyzed and discussed.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Meeting Name

Second Conference

Publisher

University of Missouri--Rolla

Publication Date

3-11-1991

Document Version

Final Version

Rights

© 1991 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Mar 11th, 12:00 AM Mar 15th, 12:00 AM

In Situ and Laboratory Tests for the Evaluation of Dynamic Geotechnical Properties of a Cohesive Deposit in Florence

St. Louis, Missouri

In order to determine dynamic parameters to use for seismic microzoning purposes in a new development area near Florence, the dynamic behavior of the alluvial silty clays situated in the upper 60 m of the deposit was experimentally investigated using geophysical surveys and cyclic laboratory tests. Previous studies on the geotechnical properties of the clays of Florence revealed that, in spite of some similarities in a comparison with other coeval clays described in the literature this soil exhibits a few anomalies, as e.g. higher variations between field and laboratory shear waves velocities and remarkable differences in the coefficients of the empirical relations that link the shear modulus to other geotechnical parameters. Moreover, many current correlations from CPT and DMT tests resulted not valid. This peculiar behavior cannot be explained in terms of cementation, because the carbonatic contents values, even if scattered, are practically normal. The objectives of the test program herein described were, therefore, as much to deepen our knowledge of the dynamic behavior of the soil both in situ and in laboratory, at low and high strain level, as to find out the reasons for this different behavior, by examining the possible influence of sample disturbance and of long-term effects, as well as of different geophysical survey techniques. The results of crosshole tests (CH), of spectral analysis of superficial waves surveys (SASW), of resonant column tests (RC) and of triaxial tests with measurement of shear and longitudinal wave velocities (Vt1), as well as the empirical relationships obtained between geotechnical parameters are analyzed and discussed.