• Geotechnical Engineering
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• v.12 no.2
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• pp.9-18
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• 1996

The results of a series of triaxial compression tests on remolded normally consolidated clay are compared with the predictions .by the isotropic single -hardening constitutive model, which incorporates eleven parameters. The parameters can be determined from undrained triaxial compression tests on isotropically consolidated specimens of remolded clay. The model with the determined parameters is applied to predict the stress-strain and pore pressure behaviors for untrained triaxial compresion tests on anisotropically consolidated specimens. Also the model is utilized to predict the stress strain and voltmetric strain behavior for drained triaxial compression tests on both isotropic and anisotropic specimens. The predicted response agrees well with the measured behavior for undrained triaxial compression tests on not only isotropically but also anisotroically but also anisotropically consolidated specimens. The initial volumetric strain is, however, predicted to be less than the measured value from drained triaxial compression tests, while the predicted volumetric strain close to failure is greater than the measured value. Nevertheless, it may be stated generally that overall acceptable predictions are produced. Therefore, the results of this study indicate that the applicability of the model on prediction of the behavior of normally consolidated clay is achieved sufficiently.

• Journal of the Korean Geotechnical Society
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• v.26 no.2
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• pp.5-14
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• 2010

In this study, cyclic triaxial tests were performed under anisotropically consolidated condition by using irregular earthquake loading to consider in-situ condition and seismic wave. Jumunjin sand with a relative density 50 percent was used in the tests. The consolidation pressure ratio (K) was changed from 0.5 to 1.0. The Ofunato and Hachinohe wave were applied as irregular earthquake loadings and liquefaction resistance strengths of each specimen were estimated from the excess pore water pressure (EPWP) ratio. As a results of the cyclic triaxial tests, EPWP ratio increased with increased K value. It shows that isotropically consolidated sand is more susceptible to liquefaction than anisotropically consolidated sand under equal confining pressure and dynamic loadings. From the test results, the relationship between K and EPWP ratio normalized by effective confining pressure and deviator stress was proposed. And a new factor which corrects the liquefaction resistance strength for the in-situ stress condition is proposed.

• Journal of the Korean Geotechnical Society
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• v.23 no.10
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• pp.47-56
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• 2007

In this research, the effects of the gravel content on the liquefaction behavior for both of the isotropically and $K_0-anisotropically$ consolidated gravel-sand mixtures are investigated. for this purpose, the cyclic triaxial tests for the specimens with the same relative density (Dr=40%) and variations of gravel content were performed. On the other hand, a series of undrained cyclic triaxial tests were carried out on the isotropically consolidated gravel-sand mixtures with the same void ratio (e=0.7) and from 0% to 30% gravel contents. Void ratios of gravel-sand mixtures with the same relative density (Dr=40%) are found to decrease significantly with the increase of the gravel content from 0% to about 70% and increase thereafter. But the void ratio of the sand matrix among the gravel skeleton increases with the increase of the gravel contents. Test results are as follows : for the isotropically consolidated specimen with 40% of relative density and low gavel contents (GC=0%, 20%, 40%), pore water pressure development and axial strain behavior during undrained cyclic loading show similar behavior to those of the loose sand because of high void ratio, and the specimens with high gravel content (70%) both pore pressure and strata behaviors are similar to those of dense sand. And the isotropically consolidated specimens with the same void ratio (e=0.7) and higher gravel contents show the same behavior of pore water pressure and axial strain as that of the loose sand, but for the lower gravel content this behavior shows similar behavior to that of dense sand. The liquefaction strength of the isotropically consolidated specimens with the same relative density increases with gravel content up to 70%, and the strength decreases with the increase of the gravel content at the same void ratio. Thus, it is confirmed that the liquefaction strength of the gravel-sand mixtures depends both on relative density and void ratio of the whole mixture rather than the relative density of the sand matrix filled among gravels. On the other hand, the behavior of pore water pressure and axial strain for the $K_0-anisotropically$ consolidated gravel-sand mixtures shows almost the same cyclic behavior of the sand with no stress reversal even with some stress reversal of the cyclic loading. Namely, even the stress reversal of about 10% of cyclic stress amplitude, the permanent strain with small cyclic strain increases rapidly with the number of cycles, and the initial liquefaction does not occur always with less than maximum pore water pressure ratio of 1.0. The liquefaction resistance increases with the gravel contents between 0% and 40%, but tends to decrease beyond 40% of gravel content. In conclusion, the cyclic behavior of gravel-sand mixtures depends on factors such as gravel content, void ratio, relative density and consolidation condition.

• Journal of the Korean GEO-environmental Society
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• v.1 no.1
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• pp.5-12
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• 2000

Mudstone, found Du-Ho Dong and around there in Po-Hang, is used as construction material. When it is exposed to the air and contacts with water, the strength is decreased rapidly and then it causes a lot of problems. In the field, clay soils with $K_o$ condition have anisotropic characteristics which behave differently according to the change of principal stress direction. In this study, $K_o$ consolidation is performed to make the completely weathered mudstone under the same conditions of construction place. Then, the triaxial compression test is performed at different shear velocity and anisotropy by sampling degree and the stress - strain behavior is shown the strain softening behavior. The stress - strain relationship from triaxial compression test is compared with the prediction value of Cam-clay model. From the results of tests, $K_o$ value decreases with the increase of sampling degree. Generally the behavior of $K_o$ consolidated specimen shows work-softening characteristic. The trend of behaviour of the measured is nearly to same to the predicted by Cam-clay model. But the measured value of deviator stress is very higher than the predicted. Therefore, Cam-clay model was not appropriate to the completely weathered mudstone consolidated with $K_o$ condition in Pohang region.