Chainage

By relation proposed by Hoek and Brown [42]

By relation proposed by Grimstad and Barton [44]

σcΘ

For Roof

For walls

σcΘ

For Roof

For walls

0+876 - 1+000

7.67

Stable

Stable

12.97

Medium stress, Favourable stress Condition

Medium stress, Favourable stress Condition

1+000 - 1+600

2.41

Severe spalling

Minor (Side wall) spalling

5.00

High Stress, Usually favourable to Stability

1+600 - 2+000

1.94

Heavy Support Required

3.62

Moderate Slabbing after 1 hour

2+000 - 2+400

1.82

Severe spalling

3.31

2+400 - 2+800

1.76

3.16

2+800 - 3+200

2.24

Severe spalling

Minor (Side wall) spalling

4.48

High Stress, Usually favourable to Stability

3+200 - 3+600

2.28

4.60

3+600 - 4+000

8.97

Stable

5.84

Medium stress, Favourable stress Condition

4+000 - 4+400

8.32

5.07

4+400 - 4+800

7.91

4.63

4+800 - 5+200

8.16

4.88

5+200 - 5+600

2.19

Severe spalling

4.31

High Stress, Usually favourable to Stability

5+600 - 6+000

6.96

Minor (Side wall) spalling

3.73

Medium stress, Favourable stress Condition

6+000 - 6+600

7.61

Stable

4.33

6+600 - 7+000

8.68

5.48

7+000 - 7+200

11.80

Stable

10.96

7+200 - 7+506

3.91

Minor (Side wall) spalling

Stable

16.44