8/16/2019 DAB20702_BAB 5 SLOPE STABILITY.pdf

1/24

Slope Stability

PREPARED BY AHMAD HAKIMI BIN MAT NOR

8/16/2019 DAB20702_BAB 5 SLOPE STABILITY.pdf

2/24

8/16/2019 DAB20702_BAB 5 SLOPE STABILITY.pdf

3/24

5.2 Soil movements / Slope instability

Falls

Topples

Slides- rotational, compound, translational

Lateral spreads

Flows

Complex or compound failure

8/16/2019 DAB20702_BAB 5 SLOPE STABILITY.pdf

4/24

5.2.1 Types of soil movements

8/16/2019 DAB20702_BAB 5 SLOPE STABILITY.pdf

5/24

8/16/2019 DAB20702_BAB 5 SLOPE STABILITY.pdf

6/24

8/16/2019 DAB20702_BAB 5 SLOPE STABILITY.pdf

7/24

8/16/2019 DAB20702_BAB 5 SLOPE STABILITY.pdf

8/24

CASE HISTORIES 1

8/16/2019 DAB20702_BAB 5 SLOPE STABILITY.pdf

9/24

8/16/2019 DAB20702_BAB 5 SLOPE STABILITY.pdf

10/24

5.3 Causes of instability

Main categories- the causes of slope instability:

• Ground conditions- weathered, fissures, etc.

• Geomorphological processes- tectonic

activities, wave erosion, etc.

• Physical processes- rainfall, tidal effects,etc.

• Man-made processes- excavation, drawdown

of water level (reservoirs), mining, quarrying,

etc.

8/16/2019 DAB20702_BAB 5 SLOPE STABILITY.pdf

11/24

Common causes of slope instability:

• Weathering effect

• Changes of slope geometry

• Decrease in effective stress of soil mass

• Excess loading (equivalent to increase in

height of slope)

• Poor design and/or construction- e.g.excavation near toe of existing slope

8/16/2019 DAB20702_BAB 5 SLOPE STABILITY.pdf

12/24

5.4 Slope stability analysis

Methods of analysis:

• Infinite slope method- plane translational

slide

• Effective and total stress approach (usually

fu = 0o)

• Fellenius or Swedish or ordinary slice

method

• Method of slices (effective stress)-   Bishop’s

method, Bishop’s modified method

8/16/2019 DAB20702_BAB 5 SLOPE STABILITY.pdf

13/24

• Taylor’s method- undrained analysis

• Bishop-Morgenstern’s method

• Janbu’s method- non-circular slip surfaces

• Wedge method- single plane

Focus:  

• Fellenius or Swedish or ordinary slice method-(rujuk

contoh kaedah hirisan)

•Kaedah menggunakan perisian Geo-slope (versi

 pelajar)

8/16/2019 DAB20702_BAB 5 SLOPE STABILITY.pdf

14/24

Contoh: Kaedah Hirisan

8/16/2019 DAB20702_BAB 5 SLOPE STABILITY.pdf

15/24

Rajah S2(c)

8/16/2019 DAB20702_BAB 5 SLOPE STABILITY.pdf

16/24

Penyelesaian:

With radius R = 14.2m, the trial surface circle has been drawn

8/16/2019 DAB20702_BAB 5 SLOPE STABILITY.pdf

17/24

Fs = 1.32>1 slope ok

8/16/2019 DAB20702_BAB 5 SLOPE STABILITY.pdf

18/24

5.5 Teknik-teknik untuk stabilkan cerun

• Membina tembok penahan(retaining wall)

• Membina tembok gabion.

• Membina sistem penambat.• Menaman rumput.

• Memasang geosintetik.

8/16/2019 DAB20702_BAB 5 SLOPE STABILITY.pdf

19/24

Tembok penahan(retaining wall)

8/16/2019 DAB20702_BAB 5 SLOPE STABILITY.pdf

20/24

Tembok gabion

8/16/2019 DAB20702_BAB 5 SLOPE STABILITY.pdf

21/24

Sistem penambat

8/16/2019 DAB20702_BAB 5 SLOPE STABILITY.pdf

22/24

Menaman rumput.

8/16/2019 DAB20702_BAB 5 SLOPE STABILITY.pdf

23/24

Geosintetik

8/16/2019 DAB20702_BAB 5 SLOPE STABILITY.pdf

24/24

END