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Geoenvironmental Disasters

Table 3 Summary of results of critical pore-water pressures and critical seepage velocities obtained from the tests

From: Critical hydraulic gradients for seepage-induced failure of landslide dams

Test specification

Test no.

Q in (m3/s)

p crit-1 (kPa)

p crit-2 (kPa)

p crit-3 (kPa)

V crit-1 (m/s)

V crit-2 (m/s)

Characteristic failure mechanism

Dam composition

Exp 1

2 × 10−4

1.30

1.24

1.08

7.10 × 10−6

5.68 × 10−6

Type I

Exp 2

2 × 10−4

1.64

1.49

1.38

1.14 × 10−6

5.39 × 10−7

Type II

Exp 3

2 × 10−4

1.45

1.35

1.34

1.49 × 10−6

1.21 × 10−6

Transitional: Type II to Type I

Rate of inflow into the upstream reservoir (filling rate)

Exp 4

1.67 × 10−5

1.47

1.35

0.98

1.05 × 10−6

7.39 × 10−7

Type I

Exp 5

5 × 10−5

1.65

1.18

0.96

1.14 × 10−6

7.15 × 10−7

Type I

Exp 6

1 × 10−4

1.68

1.20

1.01

1.18 × 10−6

7.85 × 10−7

Type II

Exp 7

1.67 × 10−4

1.52

1.50

1.19

1.07 × 10−6

1.01 × 10−6

Type II

Antecedent moisture content at low compactive effort (e o  = 1.76)

Exp 8

1.5 × 10−4

1.50

1.06

1.03

1.37 × 10−6

7.60 × 10−7

Type II

Exp 9

1.5 × 10−4

1.39

1.11

1.01

1.44 × 10−6

8.49 × 10−7

Type I

Exp 10

1.5 × 10−4

1.49

1.10

0.87

1.59 × 10−6

1.02 × 10−6

Type I

Exp 11

1.5 × 10−4

1.43

1.12

0.83

1.30 × 10−6

9.52 × 10−7

Type I

Antecedent moisture content at high compactive effort (e o  = 1.21)

Exp 12

1.3 × 10−4

1.41

1.20

1.15

1.29 × 10−6

7.60 × 10−7

Type II

Exp 13

1.3 × 10−4

1.40

1.19

1.02

1.28 × 10−6

7.50 × 10−7

Type II

Exp 14

1.3 × 10−4

1.38

1.22

0.99

1.08 × 10−6

8.50 × 10−7

Type II

Exp 15

1.3 × 10−4

1.40

1.20

0.96

1.03 × 10−6

7.98 × 10−7

Type II

Downstream slope angle

Exp 16

1 × 10−4

1.52

1.32

1.29

9.50 × 10−7

6.75 × 10−7

Type II

Exp 17

1 × 10−4

1.40

1.20

1.08

9.35 × 10−7

6.64 × 10−7

Type II

Exp 18

1 × 10−4

1.44

1.06

0.83

1.30 × 10−6

4.60 × 10−7

Type I

Exp 19

1 × 10−4

1.50

1.03

0.99

1.28 × 10−6

5.30 × 10−7

Type I

Dam height

Exp 20

1.2 × 10−4

1.13

0.78

0.98

1.24 × 10−6

5.99 × 10−7

Type I

Exp 21

1.2 × 10−4

1.48

1.21

1.22

1.38 × 10−6

8.40 × 10−7

Type II

Exp 22

1.2 × 10−4

1.60

1.40

1.29

1.40 × 10−6

8.90 × 10−7

Type II

Exp 23

1.2 × 10−4

1.72

1.37

1.01

1.43 × 10−6

9.10 × 10−7

Type II

Dam crest width

Exp 24

1.67 × 10−4

1.70

1.40

1.10

1.53 × 10−6

8.20 × 10−7

Type I

Exp 25

1.67 × 10−4

2.01

1.68

1.48

1.69 × 10−6

8.55 × 10−7

Type I

  1. Q in  = inflow rate into the upstream reservoir; p crit-1 = critical pore-water pressure for collapse of the dam crest at p1; p crit-2 = critical pore-water pressure for collapse of the dam crest at p2; p crit-3 = critical pore-water pressure for collapse of the dam crest at p3; V crit-1 = critical seepage velocity (between sensors p1 and p2); V crit-2 = critical seepage velocity (between sensors p2 and p3)
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