• Geomechanics and Engineering
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• v.21 no.6
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• pp.527-536
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• 2020

An elastic-plastic solution for cavity expansion problem considering strength degradation, undrained condition and initial anisotropic in-situ stress is established based on the Tresca yield criterion and cavity expansion theory. Assumptions of large-strain for plastic region and small-strain for elastic region are adopted, respectively. The initial in-situ stress state of natural soil mass may be anisotropic caused by consolidation history, and the strength degradation of soil mass is caused by structural damage of soil mass in the process of loading analysis (cavity expansion process). Finally, the published solutions are conducted to verify the suitability of this elastic-plastic solution, and the parametric studies are investigated in order to the significance of this study for in-situ soil test.

• Geomechanics and Engineering
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• v.19 no.2
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• pp.141-151
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• 2019

A novel theoretical solution is presented for created (zero initial radius) cavity expansion problem based on CamClay model and considers the effect of initial anisotropic in-situ stress and drained conditions. Here the strain of this theoretical solution is small deformation in elastic region and large deformation in plastic region. The works for cylindrical and spherical cavities expanding in drained condition from zero initial radius are investigated. Most of the conventional solutions were based on the isotropic and undrained condition, however, the initial stress state of natural soil mass is anisotropy by soil deposition history, and drained cavity expansion calculation is closer to actual engineering in permeable soil mass. Finally, the parametric study is presented in order to the engineering significance of this work.

• Geotechnical Engineering
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• v.12 no.6
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• pp.87-100
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• 1996

This paper verifies the accuracy and efficiency of the implicit stress integration algorithm for an anisotropic hardening constitutive model developed in a companion paper[Oh & Lee (1996)3. Simulation of undrained triaxial test results shows the accuracy of the method through an error estimation, and analyses of accuracy and convergence were performed for a numerical excavation problem. As a result, the stress was accurately integrated by the algorithm and the nonlinear solution was converged to be asymptotically quadratic. Furthermore nonlinear FE analysis of a real excavation problem was by performed considering the initial soil conditions and the in-situ construction sequences. The displacements of wall induced by excavation were more accurately estimated by the anisotropic hardening model than by the Cam-clay model.

• Journal of the Korean Geotechnical Society
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• v.18 no.5
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• pp.169-178
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• 2002

The stress~strain characteristics of geosynthetics reinforced clayey soil were investigated by triaxial compression tests. All the tests were peformed either on unreinforced or reinforced soils under fully drained condition after having been consolidated isotropically or anisotropically to the required level of effective stresses by the small increment of 0.05kgf/$cm^2$. The anisotropically consolidated drained tests were performed to simulate the in-situ condition of reinforced soil structures such as reinforced soil wall, abutment and embankment which are generally in the anisotrpic state. From a series of tests it was ffund that the behavior of the anisotropically consolidated reinforced clayey soils was very different from stress~strain characteristics of consolidated reinferced clayey soils. It was found especially that the initial Young's moduli of anisotropically consolidated reinforced clayey soils were higher than those of isotropically consolidated reinforced clayey soils. It was found also that the reinforcement effect in anisotropically consolidated reinforced soils developed at a much lower level of axial strain(0.01%) compared with isotropically consolidated ones(about 1.0~5.0%).