Lecture 2-Lateral earth pressure at rest.ppt

lateral earth pressure introduction

1. Jl. A.Yani Pabelan, Kartasura, Surakarta – Indonesia 57162
Telp.: [phone], Fax. [phone]
Website: www.ums.ac.id, email: [email protected]
LATERAL EARTH PRESSURE
DEFINITION, TYPE AND AT
REST

2. DEFINITION........
LATERAL EARTH
PRESSURE
Pressure on the wall due to
backfill thar effected by the
displacement of the wall
and soil properties

4. Basement wall Bulkheads
Dinding penahan tanah

5. z
σ
v
σ
h
= K
o
σ
v
A
B
Unit weight of soil = γ
 tan c
f

LATERAL EARTH PRESSURE AT REST
If wall AB remains static –
soil mass will be in a state
of elastic equilibrium –
horizontal strain is zero.
Ratio of horizontal stress to
vertical stress is called
coefficient of earth
pressure at rest, K
o, or

6. 
v

h
z
H


c
Shear strength of soil can be determined :
s = c + ’ tan
At the depth of z from soul surface, the vertical pressure:

v
= q + z
At zero horizontal strain, the lateral pressure:

h
= K
0
’
v
+ u
q

7. For nomally consolidated sand, Jaky (1944)
K
0
≈ 1 - sin
Brooker and Ireland (1965)
K
0 ≈ 0,95 - sin
K
0
≈ 0,4 + 0,007(PI)  0 < PI < 40
K
0
≈ 0,64 + 0,001(PI)  40 < PI < 80

8. Coefficient of earth pressure at rest (Ko)
Ratio of horizontal stress to vertical stress is called
coefficient of earth pressure at rest, K
o
, or
v
o

'


'
h
K  K

9. BASIC CONCEPT
Lateral earth pressure occurs on the wall due to backfill
Soil shear strength moilized due to friction angle
ASSUMPTION :
•Wall and soil are frictionless
•Wall is rigid and soil mass is isotropis and homogen
•At thee beginning, the condition is at rest)
The pressure at any point in a
fluid such as water is the same in
all directions
In the case of soil, which. unlike
water, the lateral pressure at
any point will not be the same as
the vertical pressure at that point

10. z

h = K
0
z
h

h
= K
0
h

11. SUBMERGED…... ????
????????????
=
1
2
??????
????????????
??????
1
2
??????1
2
+?????? ???????????? ??????
+
1
2
???????????? ??????
′
+ ??????
??????
2
??????
2
Area
ACE
Area
CEFB
Area EFG dan IJK

12. 
v

h
z
H


c
q
1
2
uK
zq
cs
vh
v






0
'
tan
K
0q K
0
H
P
2
= ½K
0
H
2
P
1
= K
0
qH
No. Weight Pressure Force Lever arm Moment
1 H K
0q K
0q H ½H ½K
0q H
2
2 H K
0H ½K
0H
2
⅓H ⅙ K
0H
3
force Moment
z
R



Force
Moment
z
R

13. H
1
H


c
q
KONDISI DIAM
H
2

sat

c
GWT
K
0
q
K
0(q+H
1+’H
2)
wH
2
1
2
5
3
4
K
0
(q+H
1
)
 
2
22
12
202
1
210
2
102
1
100
0
'
54321
HHKHHqKHKqHKP
AAAAAP
w


14. H
1
=2,5m
H=5m
=16,5 kN/m
3
=36
0
c=0
q=200 kN/m
2
EXAMPLE
H
2=2,5m

sat
=19,5kN/
m
3
=36
0
c=0
GWT
K
0
q
K
0
(q+H
1
+’H
2
)
w
H
2
1
2
5
3
4
K
0
(q+H
1
)
No.WeightPressure Force Lever arm Moment
1 2,5 82 205 3,75 768,75
2 2,5 16,913 21,141 3,333 70,469
3 2,5 98,913 247,281 1,250 309,102
4 2,5 9,932 12,415 0,833 10,346
5 2,5 24,525 30,656 0,833 25,547
   Gaya 516,493 Momen 1184,213 z =2,293
K
0
= 1 – sin  = 1 – sin 36
0
= 0,41
Pa1
Pa2
Pa3
Pa4 Pa5
Pa



Force
Moment
z
R
z
L1
L2
L5
L3
L4

15. H
1
=3,Xm
=17,Y kN/m
3
=35,Y
0
c=0
q=1X0 kN/m
2
Assigment 1
H
2=4,Ym

sat
=20,XkN/m
3
=36,X
0
c=0
GWT
Find Resultant of
lateral forces and its
point of action ?
• X = 1 last digit of NIM
• Y = 1 last digit of Mobile No
• Upload he answer sheet by Wednesday
30 Sept 2020, at 10.00 sharp

16. Te r i m a k a s i h