INTRODUCTION TO SLOPE (Kursus CreaTe) 1
INTRODUCTION TO SLOPE (Kursus CreaTe) 1
INTRODUCTION TO SLOPE (Kursus CreaTe) 1
SLOPE
DATE : 17 APRIL 2018
VENUE : CREATE, MELAKA
PRESENTER : IR NOR’AISHAH BINTI MD ALI
PRESENTATION OUTLINES
› SLOPE TERMINOLOGY
› TYPES OF SLOPE
› TYPES OF SLOPE FAILURE
› FUNDAMENTAL AND CONCEPT OF SLOPE STABILITY
› IMPORTANT FACTOR OF SLOPE STABILITY
› SLOPE ANALYSIS
› FACTOR OF SLOPE INSTABILITY
SLOPE TERMINOLOGY
Berm
Berm
Drain
Flight
Toe Cascade
Drain Drain
SLOPE TERMINOLOGY
Berm, Flight, Drainage, Buffer Zone and Height
Cut-Off Drain
Berm
Berm Drain
Flight Toe Drain
Height
Overall
Slope
Height
Flight
Slope
Angle Buffer Zone
TYPES OF SLOPE
ROCK SLOPE
NATURAL SLOPE
EMBANKMENT
CUT AND FILL SLOPE
Cut Slope
Perak Karak Highway Bentong-Gombak
Kundasang,Sabah Kenyir,Terengganu
Landslides
Erosion Falls
TYPES OF
SLOPE
FAILURES
Lateral Topple
spreads
Flows
LANDSLIDES
1. TRANSLATIONAL landslide
2. ROTATIONAL landslide
TRANSLATIONAL SLIDE
1. CREEP
2. EARTHFLOW
3. MUDFLOW
4. DEBRIS FLOW
5. DEBRIS AVALANCHE
CREEP
A group of trees on a slope where the base of each tree bows outward in the
downslope direction
EARTHFLOW
CHARACTERISTIC:
a. Moderate-to-slope.
CHARACTERISTIC:
CHARACTERISTIC:
CHARACTERISTIC:
CHARACTERISTIC:
Sheet Erosion
Creep
Rill Erosion
Gully Erosion
Suspension
Stream-Bank Erosion
FUNDAMENTAL AND CONCEPT
OF SLOPE STABILITY
What is the factor of Slope
Stability?
Slope stability is based on the interplay between
two types of forces , driving and resisting forces.
R
SLOPE STABILITY
Factor of Safety(FOS) is equals to
the ratio of resisting forces to
driving forces.
𝑅𝐸𝑆𝐼𝑆𝑇𝐼𝑁𝐺 𝐹𝑂𝑅𝐶𝐸(𝑁)
𝐹𝑂𝑆 =
𝐷𝑅𝐼𝑉𝐼𝑁𝐺 𝐹𝑂𝑅𝐶𝐸(𝐷)
If FOS > 1 then SAFE
If FOS < 1 UNSAFE
(Refering to JKR Guidelines 2010 FOS> 1.3 for
natural slopes, FOS >1.5 for man-made slopes)
The main driving force in most land
movements is gravity
Slope angle,climate,slope material,and water
contribute to the effect of gravity
Driving forces promote downslope
movement of material
Gravity Gravity
Normal
Force
Mass
The main resisting force is the material’s
shear strength
Resisting forces deter movement
IMPORTANT SLOPE
STABILITY FACTORS
1. Soil Properties
CONCEPT OF FRICTION
Gravity
Driving Force
Resistance Force
Act by Friction
(Soil shear strength properties)
2. Geometric Factors
1. SLOPE HEIGHT
The higher the height of the slope, the greater the
shear stress of the slope.
Thus, reducing the Factor of Safety of the slope.
2. Geometric Factors
2. SLOPE ANGLE AND FORCES
H = 17 m H = 17 m
L = 39 m CENTER L = 33 m
1.486
= 32
= 45
70 BH 1
Description: Soil 1
Wt: 18
65 C: 5
Phi: 28 BH 2
Elevation (M)
60 Description: Soil 2 BH 3
? ?
Wt: 18 1
C: 10 ? ? 2
55
Phi: 30
?
Description: Soil 3 ? ?
50
Wt: 18
4 3
C: 3
45 Phi: 35 ? ?
Description: Bedrock
40
-39 -34 -29 -24 -19 -14 -9 -4 1 6 11 16 21 26 31
Distance (M)
FOS CALCULATION METHODS
b
B
A
α
Z
C’ =13.5 kN/m2
γ =16.5 kN/m3
𝑏
𝑙=
cos 𝛼 l Φ’ =15°
Table Of Analysis
𝑅𝑒𝑠𝑖𝑠𝑡𝑖𝑛𝑔 𝐹𝑜𝑟𝑐𝑒 σ ∁′ 𝐿 +ΣW cos 𝛼 tan Φ
F.O.S = 𝐷𝑟𝑖𝑣𝑖𝑛𝑔 𝐹𝑜𝑟𝑐𝑒
= σ 𝑊 sin 𝛼
Slice α Z (m) b (m) W=γbz W Sinα W l
Cosα
1 -7 3.4 2.5 140.25 -17.09 139.2 2.52
PHI , Φ F.O.S
3.34
45 3.34
2.98
41 2.98
2.75
38 2.75
2.53
35 2.53
2.39
33 2.39 2.26
31 2.26 2.13
29 2.13 2.01
1.89
27 2.01
25 27 29 31 33 35 38 41 45
25 1.89 PHI,Φ
EFFECTS OF COHESION (C’) ON
FACTOR OF SAFETY
Unit Weight,γ = 16.5 FOS
Slope Angle,Φ’= 15
COHESION,C F.O.S
1.35
13.5 1.35
1.30
12.5 1.3
1.26
11.5 1.26
1.21
10.5 1.21
1.16
9.5 1.16 1.12
8.5 1.12 1.07
.1.129
.1.304
1V:1H
1V:1.5H
The gentler the slope the higher the Factor of Safety of the slope
EFFECTS OF GROUND WATER TABLE ON
FACTOR OF SAFETY
EFFECTS OF GROUND WATER TABLE
ON FACTOR OF SAFETY
1.129
0.844
The present of ground water table within the slip plane the lower the Factor of Safety of the
slope
EFFECTS OF GROUND WATER TABLE
ON FACTOR OF SAFETY
1.859 .1.859
1.566
Construction
Maintenance
Error
FACTORS
CONTRIBUTED
TO SLOPE
INSTABILITY
REFERENCE: IEM
HUMAN ERRORS INVOLVING SLOPE
FAILURE
Design Errors 29 60
Construction Errors 4 8
Maintenance 3 6
Total 49 100