PSI - Issue 28

M. Zhelnin et al. / Procedia Structural Integrity 28 (2020) 693–701 Author name / Structural Integrity Procedia 00 (2019) 000–000

698

6

c

a

b

Fig. 1. (a) The computational domain (saturated silty sand (cyan), the concrete shell (yellow), the cast iron tubing (green)) and a scheme of boundary conditions. (b) Initial distribution of the temperature T ◦ C (the black line corresponds to the phase transition boundary). (c) Initial distribution of the porosity n (the black line corresponds to the phase transition boundary).

a

b

Fig. 2. Distribution of the grout concentration C (kg/m 3 ) after the gout injection for 24 hours through two boreholes (a) and three boreholes (b). The white line corresponds to the position of the phase transition boundary. were determined by a numerical simulation of the ice-soil formation based on the proposed THM model. Fig. 2 demonstrates grout concentration obtained by numerical simulation. It can be seen that the frozen ground inhibits the grout flow. Therefore, the grout flows in the unfrozen soil along the lining side. Due to an influence of the gravitation force the grout propagates more intensively to the bottom boundary than to the top one. As the grout flows the pore pressure flattens and the grout velocity decreases. In the case of the injection through two boreholes the gradient decrease leads to the more intensive grout propagation in the direction opposite to the region between the boreholes. In the case of injection using the three boreholes domains with a low grout concentration arise. Besides the grout injected through the middle borehole propagates to shorter distance than the grout injected from the other ones. Distributions of the temperature in the soil stratum are presented in Fig. 3. It can be seen that the grout injection and heat dissipation caused by cement hydration induce a rise in temperature of the soil. Near the

a

b

Fig. 3. Distribution of the temperature T ◦ C after the grout injection for 24 hours through two boreholes (a) and three boreholes (b). The white line corresponds to the position of the phase transition boundary.