PSI - Issue 18

Kostina A. et al. / Procedia Structural Integrity 18 (2019) 293–300 Author name / Structural Integrity Procedia 00 (2019) 000–000

297

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Table 2. Mechanical properties of soils Soil K, Pa G, Pa

s  , 1/K

B 

Sandstone

5.91ꞏ10 9 8.08ꞏ10 9 2.82ꞏ10 9 2.33ꞏ10 9 1.92ꞏ10 8 1.54ꞏ10 8

2.14ꞏ10 -5

4.51ꞏ10 -1 5.07ꞏ10 -1 5.72ꞏ10 -1

Sand Clay

5ꞏ10 -6

0

In Fig. 2(b), Fig. 3(a) distributions of mechanical pressure p in the computational domain and along the well boundary 1  are presented at 186 t  day after that the freezing has started. The results are shown that the distributions are nonhomogeneous. The maximum value of the pressure is observed in the sandstone stratum with the largest coefficient of thermal diffusivity in the frozen state. The freezing process in the stratum has a largest rate. From Fig. 3(a) it can be seen that the mechanical pressure reaches local maximal values at the interfaces of the stratums. In Fig. 3(b) distribution of p along the well boundary 1  is shown at 206 t  day when the soil thawing has started already. The distribution is in qualitative agreement with the distribution in Fig. 3(a) for the case of freezing. However, in the case of thawing local maximal values of p at the interfaces of the stratums are significantly less than the ones presented in Fig. 3(a).

b

a

Fig. 2. (a) temperature

p T of liquid circulating in the freezing well in depending on time t ; (b) distribution of the mechanical pressure p in the

soil stratums under consideration

b

a

186 t  day (a) and

206 t  day (b).

Fig. 3. Distribution of the mechanical pressure p along the well boundary

1  at the time moments