active lateral earth pressure

1. Jl. A.Yani Pabelan, Kartasura, Surakarta – Indonesia 57162
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Website: www.ums.ac.id, email: ums@ums.ac.id
ACTIVE LATERAL EARTH
PRESSURE

2. ACTIVE LAERAL EARTH PRESSURE
Plastic equilibrium in soil refers to the condition where every point in a soil
mass is on the verge of failure.
If wall AB is allowed to move away from the soil mass gradually,
horizontal stress will decrease.
This is represented by Mohr’s circle in the subsequent slide.

3. RANKINE THEORY

4. ASSUMPTIONS
1. Wall and soil are frictionless
2. Wall is vertical 90°.
3. Type of failure is shear failure
4. Lateral pressure is linier to the depth.

5. When wall moves from
A to A’, effective
horizontal pressure
will decrease with a
consant effective
ertical pressure
• The active failure
occurs as the Mohr
circle gets the
failure envelopek

6. f,
kan

8. DIAGRAM OF ACTIVE PRESSURE
For dry cohesionless Backfill
𝜎𝑎 = 𝐾𝑎. 𝛾𝑧
(c = 0)
𝜎𝑎 = 𝐾𝑎. 𝛾𝐻
Gaya total Pa
adalah :
1
2
𝑎
𝑎
𝑃 = 𝐾 .
𝛾𝐻
2

9. • cohesionless backfill
•Ground water level
•Surcharged load

11.  
a
a
a
a
a
a
a
a
H
a
H
a
H
a
K
c
K
H
K
c
HK
HK
K
cH
K
H
dz
K
c
dz
zK
dz
P












2
2
0
0
0
2
1
2
2
1
2
2
1
2




• cohesive backfill

12. - =
H
zc
Kav





 







 









 







 









 







 




2
45
tan
2
2
45
tan
2
45
tan
2
2
45
tan
2
45
tan
2
2
45
tan
2
2
2
c
c
c
v
a
v
a
a
v





 


2
45
tan2
a
K
a
a
v
a K
c
K 2









 


2
45
tan
a
K

13. ?

14. EKANAN TANAH AKTIF, RANKINE
c
wZ

H-Zc
R
Pa1
Pa2
Pa
 






















 


Pa
Zc
Zc
H
Pa
Zc
H
Pa
R
3
3
2
1
3
Zc
H 
 
3
Zc
Zc
H 


15. T e r i m a k a s i h