PSI - Issue 32

S.S. Andreiko et al. / Procedia Structural Integrity 32 (2021) 3–9 V.Anikin / Structural Integrity Procedia 00 (2021) 000–000

7

5

equation has the following form: = 6,68 ∙ −0 , 55

(16) where is the radius of crack formation zone, m; is the rock strength for uniaxial compression, MPa. The coefficient of determination of the indicated dependence is 2 = 0.98.

Fig. Dependence of the radius of the fractured zone (m) on the strength of rocks (MPa) Physicomechanical and calculated characteristics of the rocks according to data [2, 6, 8, 9, 10, 11] are given in Table 1.

Table 1Rock Characteristics (when using ammonite 6 ZhV)

, kg/m 3 , m/s

, MPa , unit fraction ,

KPa·s 1 ,

MPa 2 ,

MPa , m

Rock

1

2

3

4

4

5

6

7

8

Sylvinite Syenite

2020 2600 2730 2730 2850 2440 2650 2850 2710 2600 2930 2710 2630 2590 2910 3100 2630

3820 1796 3021 4420 6080 5040 6420 5400 6410 5200 6410 5750 5220 3380 7140 5640 5100

30

1.86 1.99 1.84 1.72 1.60 1.72 1.61 1.64 1.60 1.69 1.58 1.64 1.68 1.82 1.54 1.60 1.69

163.0 138.6 278.4 636.4 1432 1124 1771 1623 1857 1474 2113 1928 2076 1459 3769 3196 3160

3.94 1.75 4.42 8.2 15.6 8.7 15.5 12.6 15.6 10.5 18.2 13.3 10.7 22.3 16.4 10.2 5.0

5.9 3.6 6.4 9.2

1.05 0.76 0.80 0.65 0.53 0.47 0.45 0.44 0.44 0.42 0.43 0.40 0.35 0.31 0.32 0.31 0.26

42.2 48.0 75.0

Cracked quartzite White marble

Gneiss

117.5 130.0 148.0 150.0 152.0 155.0 160.0 176.0 215.0 237.0 258.0 260.0 335.0

13.3 9.5 13.1 11.9 13.5 10.2 14.5 12.0 10.6 15.9 13.3 10.2 6.7

Diabase 1 porphyritic

Quartzite 2

Gabbro-diabase 1 Granite-gneiss

Granite* Porphyrite Sandstone 3 Hornstone Slate 3

Diabase 2 porphyritic

Gabbro-diabase 2 Quartz porphyrite

* -physical and mechanical characteristics of granite according to Table 1 [6]. Here, the stress in the rock 1 is calculated for the distance 100 ′ , taking into account the formulas (9, 12): 1 ( ′ ) = ′ ⁄ (17)