PSI - Issue 17

M. Zhelnin et al. / Procedia Structural Integrity 17 (2019) 316–323 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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b

Fig. 4. (a) distribution of the mechanical pressure (blue line) and Mises stress (green line) along the boundary of the freezing well at t = 200 day; (b) distribution of effective plastic strain in the second computational domain at t = 200 day.

observed. In Fig. 5 distribution of the radial displacement and the vertical displacement are shown at t = 200 day. It can be seen that within the phase transition zone radial displacement increases. Similar to results presented in Fig. 2(b), the soil stratums are subsided to down. Maximal value of the vertical displacement attains at the interface of clay and sand stratums.

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Fig. 5. Distributions of the radial displacement (a) and the vertical displacement (b) in the second computational domain at t = 200 day. White lines denote boundaries of the phase transition zone.

4. Conclusions

This article presents a study of mechanical behavior of soils during a vertical mine shaft construction with a use of the AGF method on the basis of a numerical simulation. To study of the mechanical behavior a thermo-hydro mechanical model of freezing process in water saturated soils has been developed. The model allows us to perform coupled analysis of water filtration, distributions of temperature, stress and strain fields under taking into account the phase transition. Description of stress-strain state of soils during freezing is conducted in consideration of elasto plastic strain induced by frost heave and temperature change. Plastic strain is estimated with using Drucker-Prager criterion. In the work the numerical simulation has been carried out for two problems. In all cases three soil stratums with different thermophysical, hydrodynamics and mechanics properties have been considered. In the first case a soil response on an application of the AGF method and a shaft sinking has been analyzed in the elastic statement. It has