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RETAINING EARTH STRUCTURE Session 11 – 16 Course: S0825/Foundation Engineering Year: 2009.

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Presentation on theme: "RETAINING EARTH STRUCTURE Session 11 – 16 Course: S0825/Foundation Engineering Year: 2009."— Presentation transcript:

1 RETAINING EARTH STRUCTURE Session 11 – 16 Course: S0825/Foundation Engineering Year: 2009

2 Bina Nusantara RETAINING EARTH STRUCTURE Topic: Lateral Earth Pressure – General – Active earth pressure Rankine earth pressure Coulomb earth pressure Lateral earth pressure due to surcharge – Passive earth pressure Rankine earth pressure Coulomb earth pressure – Influence of ground water table Sheet Pile Structure – General – Types of Sheet Pile – Lateral Pressure Diagram – Cantilever Sheet Pile

3 Bina Nusantara LATERAL EARTH PRESSURE SESSION 11 – 12

4 Bina Nusantara GENERAL Lateral earth pressure represents pressures that are “to the side” (horizontal) rather than vertical. Caused by soil self weight and or external load 3 categories: –At rest earth pressure –Active earth pressure –Passive earth pressure

5 Bina Nusantara AT REST EARTH PRESSURE The at rest pressure develops when the wall experiences no lateral movement. This typically occurs when the wall is restrained from movement such as a basement wall that is supported at the bottom by a slab and at the top by a floor framing system prior to placing soil backfill against the wall.

6 Bina Nusantara ACTIVE EARTH PRESSURE The active pressure develops when the wall is free to move outward such as a typical retaining wall and the soil mass stretches sufficiently to mobilize its shear strength.

7 Bina Nusantara PASSIVE EARTH PRESSURE If the wall moves into the soil, then the soil mass is compressed sufficiently to mobilize its shear strength and the passive pressure develops.

8 Bina Nusantara AT REST EARTH PRESSURE q vv hh z  v = . z + q At rest, K = K o Jaky, Broker and Ireland  Ko = M – sin  ’ Sand, normally consolidated clay  M = 1 Clay with OCR > 2  M = 0.95 Sherif and Ishibashi  K o = +  (OCR – 1) = (LL – 20)  = (LL – 20) LL > 110%  = 1.0 ;  = 0.19 Broker and Ireland K o = PI, 0  PI  40 K o = PI, 40  PI  80

9 Bina Nusantara ACTIVE EARTH PRESSURE

10 Bina Nusantara RANKINE ACTIVE EARTH PRESSURE Ka = tan 2 (45 -  /2)  1 =  3. tan 2 (45+  /2)+2c.tan (45+  /2)  a =  v. tan 2 (45-  /2) – 2c. tan (45-  /2)  a =  v. Ka – 2c  Ka

11 Bina Nusantara RANKINE ACTIVE EARTH PRESSURE (INCLINED BACKFILL) (for granular soil, c = 0) For c-  soil

12 Bina Nusantara COULOMB ACTIVE EARTH PRESSURE Assumptions: -Fill material is granular soil - Friction of wall and fill material is considered - Soil failure shape is plane (BC 1, BC 2 …) Pa = ½ Ka. . H 2

13 Bina Nusantara COULOMB ACTIVE EARTH PRESSURE (SURCHARGE ON BACKFILL)

14 Bina Nusantara RANKINE PASSIVE EARTH PRESSURE

15 Bina Nusantara RANKINE PASSIVE EARTH PRESSURE  p =  v. tan 2 (45+  /2) + 2c. tan (45+  /2)

16 Bina Nusantara RANKINE PASSIVE EARTH PRESSURE Kp = tan 2 (45 +  /2)  h =  v. Kp + 2c  Kp

17 Bina Nusantara COULOMB PASSIVE EARTH PRESSURE Pp = ½ Kp. . H 2

18 Bina Nusantara LATERAL EARTH PRESSURE DUE TO SURCHARGE a > 0,4 a  0,4

19 Bina Nusantara LATERAL EARTH PRESSURE DUE TO SURCHARGE

20 Bina Nusantara PURPOSE OF LATERAL EARTH PRESSURE STABILITY ANALYSIS GRAVITY WALL AGAINST –SLIDING –OVERTURNING

21 Bina Nusantara PURPOSE OF LATERAL EARTH PRESSURE

22 Bina Nusantara PURPOSE OF LATERAL EARTH PRESSURE

23 Bina Nusantara SHEET PILE STRUCTURES SESSION 13 – 14

24 Bina Nusantara SHEET PILE

25 Bina Nusantara GENERAL Connected or semi-connected sheet piles are often used to build continuous walls to retain the lateral pressure caused by soil or external load. In contrast to the construction of other types of retaining wall, the building of sheet pile walls do not usually require dewatering the site. Sheet piles are also used for some temporary structures, such as braced cut.

26 Bina Nusantara SHEET PILE TYPES (CANTILEVER)

27 Bina Nusantara Free Earth Support SHEET PILE TYPES (ANCHORED)

28 Bina Nusantara Fixed Earth Support SHEET PILE TYPES (ANCHORED)

29 Bina Nusantara anchor plate or beam SHEET PILE TYPES (ANCHORED)

30 Bina Nusantara tie back vertical anchor pile SHEET PILE TYPES (ANCHORED)

31 Bina Nusantara anchor beam with batter piles SHEET PILE TYPES (ANCHORED)

32 Bina Nusantara LATERAL EARTH PRESSURE DIAGRAM

33 Bina Nusantara LATERAL EARTH PRESSURE DIAGRAM

34 Bina Nusantara Fixed Earth Support LATERAL EARTH PRESSURE DIAGRAM

35 Bina Nusantara Free Earth Support LATERAL EARTH PRESSURE DIAGRAM

36 Bina Nusantara Free Earth Support LATERAL EARTH PRESSURE DIAGRAM

37 Bina Nusantara CALCULATION STEPS CANTILEVER SHEET PILE - SAND

38 Bina Nusantara CALCULATION STEPS CANTILEVER SHEET PILE - SAND 1. Determine the value of K a and K p 2. Calculate p 1 and p 2 with L 1 and L 2 are known 3. Calculate L 3 4. Calculate the resultant of the area ACDE (P) 5. Determine the z (the center of pressure for the area ACDE)

39 Bina Nusantara CALCULATION STEPS CANTILEVER SHEET PILE - SAND 6. Calculate p 5 7. Calculate A 1, A 2, A 3, A 4

40 Bina Nusantara CALCULATION STEPS CANTILEVER SHEET PILE - SAND 8. Determine L 4 9. Calculate p Calculate p Calculate L Draw the pressure distribution diagram 13. Obtain the theoretical depth ; D = L 3 + L 4 The actual depth of penetration is increased by about 20% - 30% 14. Calculate the maximum bending moment

41 Bina Nusantara EXAMPLE CANTILEVER SHEET PILE - SAND GWL  d = 15.9 kN/m 3  t = kN/m 3  = 32 o c = 0 kPa L 1 = 2 m L 2 = 3 m D Determine the penetration depth (D) and dimension of sheet pile

42 Bina Nusantara EXAMPLE CANTILEVER SHEET PILE - SAND Step 1 (determine the value of k a and k p ) Step 2 (calculate p 1 and p 2 ) Step 3 (Calculate L 3 ) kPa m

43 Bina Nusantara EXAMPLE CANTILEVER SHEET PILE - SAND Step 4 (calculate P) Step 5 (calculate z) Step 6 (calculate p 5 ) kN/m m kN/m 2

44 Bina Nusantara EXAMPLE CANTILEVER SHEET PILE - SAND Step 7 (calculate A 1 – A 4 )

45 Bina Nusantara EXAMPLE CANTILEVER SHEET PILE - SAND Step 8 (determine L 4 ) Step 9 (calculate p 4 ) Step 10 (calculate p 3 ) L 4  4.8 m kPa

46 Bina Nusantara EXAMPLE CANTILEVER SHEET PILE - SAND Step 11 (Calculate L 5 ) Step 12 Draw the pressure distribution diagram Step 13 (the penetration dept of sheet pile) –Theoretical = = 5.46 m –Actual = 1.3 (L 3 +L 4 ) =7.1 m m

47 Bina Nusantara EXAMPLE CANTILEVER SHEET PILE - SAND

48 Bina Nusantara EXAMPLE CANTILEVER SHEET PILE - SAND Dimension of Sheet Pile m kN.m

49 Bina Nusantara SHEET PILE STRUCTURE SESSION 15 – 16

50 Bina Nusantara CALCULATION STEPS CANTILEVER SHEET PILE - CLAY

51 Bina Nusantara CALCULATION STEPS CANTILEVER SHEET PILE - CLAY 1. Determine the value of K a and K p 2. Calculate p 1 and p 2 with L 1 and L 2 are known 3. Calculate the resultant of the area ACDE (P 1 ) and z 1 (the center of pressure for the area ACDE) In case of saturated soft clay with internal friction angle (  ) = 0, we got K a = K p = 1

52 Bina Nusantara CALCULATION STEPS CANTILEVER SHEET PILE - CLAY 4. Calculate the theoretical penetration depth of sheet pile (D) 5. Calculate L 4 6. Calculate p 6 and p 7 7. Obtain the actual penetration depth of sheet pile D actual = (1.4 – 1.6) x D theoretical

53 Bina Nusantara CALCULATION STEPS CANTILEVER SHEET PILE - CLAY 8. Calculate the maximum bending moment

54 Bina Nusantara EXAMPLE CANTILEVER SHEET PILE - CLAY GWL  d = 15.9 kN/m 3  t = kN/m 3  = 32 o c = 0 kPa L 1 = 2 m L 2 = 3 m D Determine the penetration depth (D) and dimension of sheet pile Clay sand c u = 47 kPa  = 0 o

55 Bina Nusantara EXAMPLE CANTILEVER SHEET PILE - CLAY Step 1 (Determine k a and k p ) Step 2 (calculate p 1 and p 2 ) Step 3 (calculate P 1 and z 1 ) kPa kN/m m

56 Bina Nusantara EXAMPLE CANTILEVER SHEET PILE - CLAY Step 4 (obtain D theoretical ) Step 5 (calculate L 4 ) D = 2.13 m L 4 = 2.13 m

57 Bina Nusantara EXAMPLE CANTILEVER SHEET PILE - CLAY Step 6 (calculate p 6 and p 7 ) Step 7 (draw the lateral diagram) Step 8 (Obtain D actual ) kN/m 2 D actual = 1.5 x D theorical = 1.5 x 2.13 = 3.2 m

58 Bina Nusantara EXAMPLE CANTILEVER SHEET PILE - CLAY Calculation of moment

59 Bina Nusantara CALCULATION STEPS ANCHORED SHEET PILE – FREE – SAND

60 Bina Nusantara CALCULATION STEPS ANCHORED SHEET PILE – FREE – SAND 1. Determine the value of K a and K p 2. Calculate p 1 and p 2 with L 1 and L 2 are known 3. Calculate L 3 4. Calculate P as a resultant of area ACDE 5. Determine the center of pressure for the area ACDE ( z )

61 Bina Nusantara CALCULATION STEPS ANCHORED SHEET PILE – FREE – SAND Determination of penetration depth of sheet pile (D) D theoretical = L 3 + L 4 D actual = (1.3 – 1.4) D theoretical Determination of anchor force F = P – ½ [  ’(K p – K a )]L Calculate L 4

62 Bina Nusantara CALCULATION STEPS ANCHORED SHEET PILE – FREE – CLAY

63 Bina Nusantara CALCULATION STEPS ANCHORED SHEET PILE – FREE – CLAY 1. Determine the value of K a and K p 2. Calculate p 1 and p 2 with L 1 and L 2 are known 3. Calculate the resultant of the area ACDE (P 1 ) and z 1 (the center of pressure for the area ACDE) In case of saturated soft clay with internal friction angle (  ) = 0, we got K a = K p = 1

64 Bina Nusantara CALCULATION STEPS ANCHORED SHEET PILE – FREE – CLAY 5. Determination of penetration depth of sheet pile (D) p 6.D p 6.D.(L 1 +L 2 -l 1 ) – 2.P 1.(L 1 +L 2 -l 1 -z 1 ) = 0 6. Determination of anchor force F = P 1 – p 6. D 4. Calculate p 6

65 Bina Nusantara CALCULATION STEPS ANCHORED SHEET PILE – FIXED – SAND J

66 Bina Nusantara CALCULATION STEPS ANCHORED SHEET PILE – FIXED – SAND 1. Determine the value of K a and K p 2. Calculate p 1 and p 2 with L 1 and L 2 are known 3. Calculate L 3

67 Bina Nusantara CALCULATION STEPS ANCHORED SHEET PILE – FIXED – SAND 4. determine L 5 from the following curve (L 1 and L 2 are known)

68 Bina Nusantara CALCULATION STEPS ANCHORED SHEET PILE – FIXED – SAND 5. Calculate the span of the equivalent beam as l 2 + L 2 + L 5 = L’ 6. Calculate the total load of the span, W. This is the area of the pressure diagram between O’ and I 7. Calculate the maximum moment, M max, as WL’/8

69 Bina Nusantara CALCULATION STEPS ANCHORED SHEET PILE – FIXED – SAND 8. Calculate P’ by taking the moment about O’, or 9. Determine D 10. Calculate the anchor force per unit length, F, by taking the moment about l, or (moment of area ACDJI about O’) (moment of area ACDJI about I)


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