Open AccessAnalysis of yield stress ratio and overconsolidation ratio as parameter determination preconsolidation in eemian gyttja
Author(s) -
Edyta Malinowska,
Marek Bajda
Publication year - 2018
Publication title -
annals of warsaw university of life sciences-sggw. land reclamation
Language(s) - English
Resource type - Journals
eISSN - 2081-9617
pISSN - 1898-8857
DOI - 10.2478/sggw-2018-0009
Subject(s) - oedometer test , geotechnical engineering , subsoil , yield (engineering) , stress (linguistics) , geology , overburden pressure , soil water , materials science , soil science , composite material , linguistics , philosophy
The preconsolidation stress is an important phenomenon that determines the value of stress history exerted in the past on the subsoil in the geotechnical engineering. Overconsolidation ratio ( OCR ) is one of the main criteria conditioning soil behaviour and its characteristics. Here thought, the yield stress ratio ( YSR ) is used to determine the value of preconsolidation stress resulting from mechanical overburden than can be changed by many post depositional processes like secondary and tertiary compressibility, cementation, aging, temperature change and others. The yield stress ratio ( YSR ) is defined as the relationship between vertical yield stress ( σ ’ vy ) to the effective vertical stress ( σ ’ v 0 ). The eemian gyttja was used as a foundation in the engineering construction. In practical geotechnical engineering, evaluation of stress history is usually based on the overconsolidation ratio ( OCR ). The yield stress ratio ( YSR ) was used in the laboratory as one of the basic parameters for the geotechnical design of the structure. To know the relation between geological background, history and mechanical behaviour in long-time process of the soil aims a knowledge that can help engineers who often have to predict soil behaviour based upon the soil geological history and a few geotechnical data. In order to evaluate the yield stress ratio of eemian gyttja it is necessary to restore this soft, organic soil as much as possible to the in situ conditions. The laboratory tests were used to determinate the vertical yield stress and then the yield stress ratio. The laboratory tests were made in the automatic oedometer and the in situ tests were carried out on the dilatometer test (DMT). The comparison between the determination the yield stress ratio of eemian gyttja from the laboratory and the overconsolidation ratio from in situ test has been done. The studies have shown that the values of the overconsolidation ratio determinate from the laboratory tests are a little higher than determinate from the in situ tests.