Location

San Diego, California

Session Start Date

3-26-2001

Session End Date

3-31-2001

Abstract

Dynamic centrifuge modeling requires special boundary conditions in order to minimize the effects of model containers on the performance of the soil within them, especially due to reflection of stress waves. This concern has lead to the development of the Equivalent Shear Beam (ESB) model container, which matches container stiffness to that of the soil column, the performance of which is evaluated in this paper. A series of centrifuge test involving loose and dense, dry and saturated models of homogeneous horizontal sand layers have been carried out, and measurements taken to quantify the effects of the boundaries on soil behaviour. Miniature Cone Penetration Tests (CPT) were conducted in fIight, before and after earthquake loading to investigate boundary effects on the densification of sand near the end walls during dynamic loading, and arching of soil and shear transfer to the end-walls. The influence of boundary effects is shown based on centrifuge test data by comparing CPT profiles adjacent to the end walls with those taken near the center of the model container. The results verily the uniformity of the soil model prior to earthquake loading. Also they show that the penetration resistance changes after the earthquake loading. In case of loose dry sands, there is densification at the boundary relative to the center of model. In case of loose saturated models, the densification occurred at the middle of the model relative to the boundary region.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

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

Meeting Name

Fourth Conference

Publisher

University of Missouri--Rolla

Publication Date

3-26-2001

Document Version

Final Version

Rights

© 2001 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Mar 26th, 12:00 AM Mar 31st, 12:00 AM

CPT Assessment of Boundary Effects in Dynamic Centrifuge Modelling

San Diego, California

Dynamic centrifuge modeling requires special boundary conditions in order to minimize the effects of model containers on the performance of the soil within them, especially due to reflection of stress waves. This concern has lead to the development of the Equivalent Shear Beam (ESB) model container, which matches container stiffness to that of the soil column, the performance of which is evaluated in this paper. A series of centrifuge test involving loose and dense, dry and saturated models of homogeneous horizontal sand layers have been carried out, and measurements taken to quantify the effects of the boundaries on soil behaviour. Miniature Cone Penetration Tests (CPT) were conducted in fIight, before and after earthquake loading to investigate boundary effects on the densification of sand near the end walls during dynamic loading, and arching of soil and shear transfer to the end-walls. The influence of boundary effects is shown based on centrifuge test data by comparing CPT profiles adjacent to the end walls with those taken near the center of the model container. The results verily the uniformity of the soil model prior to earthquake loading. Also they show that the penetration resistance changes after the earthquake loading. In case of loose dry sands, there is densification at the boundary relative to the center of model. In case of loose saturated models, the densification occurred at the middle of the model relative to the boundary region.