PSI - Issue 32

M. Zhelnin et al. / Procedia Structural Integrity 32 (2021) 71–78 M. Zhelnin/ Structural Integrity Procedia 00 (2021) 000–000

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(a)

(b)

Fig. 7. Distribution of the equivalent (a) and volumetric (b) plastic strains in the concrete shell with the thickness of 2.47 m (The black line denotes interface between the concrete shell and grouted sand)

(a)

(b)

Fig. 8 Ratio of the optimal Young’s modulus of the concrete shell to the modulus of the grouted sand (a) and the optimal thickness of the concrete shell (b) vs thickness of the grouted sand layer. In case (a) the thickness of the concrete shell and the Young’s modulus of the grouted soil are assumed to be equal to the projected values of 0.45 m and 11.5 GPa. In case (b) the Young’s modulus of the concrete shell and the thickness of the grouted soil layer are assumed to be equal to the projected values of 24 GPa and 2.7 m.

(a)

(b)

Fig. 9 Ratio of the optimal Young’s modulus of the concrete shell to the modulus of the grouted sand (a) and the optimal thickness of the concrete shell (b) vs lateral pressure. In case (a) the thickness of the concrete shell and the Young’s modulus of the grouted soil are assumed to be equal to the projected values of 0.45 m and 11.5 GPa. In case (b) the Young’s modulus of the concrete shell and the thickness of the grouted soil layer are assumed to be equal to the projected values of 24 GPa and 2.7 m. of 240 m the optimal Young’s modulus reduces by 30% and the optimal thickness rises by 4 times compared with the optimal parameters for the depth of 190 m. Thus, the thickness of the concrete shell has minor influence on the stress strain state in the concrete lining with a rise in the depth. The reduction of the stiffness of the concrete shell is more preferable to prevent plastic deformation in the concrete shell. However, from the practical point of view excessive stiffness reduction can lead to significant bending of the concrete shell, so the strength properties have to be also improved with the depth.