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**RETAINING EARTH STRUCTURE Session 11 – 16**

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

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**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 Influence of ground water table Sheet Pile Structure Types of Sheet Pile Lateral Pressure Diagram Cantilever Sheet Pile Bina Nusantara

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**LATERAL EARTH PRESSURE**

SESSION 11 – 12 Bina Nusantara

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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 Bina Nusantara

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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. Bina Nusantara

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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. Bina Nusantara

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**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. Bina Nusantara

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**AT REST EARTH PRESSURE Jaky, Broker and Ireland Ko = M – sin ’**

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

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ACTIVE EARTH PRESSURE Bina Nusantara

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**RANKINE ACTIVE EARTH PRESSURE**

1 = 3 . tan2 (45+/2)+2c.tan (45+/2) a = v . tan2(45-/2) – 2c . tan (45-/2) a = v . Ka – 2cKa Ka = tan2 (45 - /2) Bina Nusantara

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**RANKINE ACTIVE EARTH PRESSURE (INCLINED BACKFILL)**

(for granular soil, c = 0) For c- soil Bina Nusantara

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**COULOMB ACTIVE EARTH PRESSURE**

Assumptions: Fill material is granular soil Friction of wall and fill material is considered Soil failure shape is plane (BC1, BC2 …) Pa = ½ Ka . . H2 Bina Nusantara

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**COULOMB ACTIVE EARTH PRESSURE (SURCHARGE ON BACKFILL)**

Bina Nusantara

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**RANKINE PASSIVE EARTH PRESSURE**

Bina Nusantara

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**RANKINE PASSIVE EARTH PRESSURE**

p= v . tan2(45+/2) + 2c . tan (45+/2) Bina Nusantara

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**RANKINE PASSIVE EARTH PRESSURE**

Kp = tan2 (45 + /2) h = v . Kp + 2cKp Bina Nusantara

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**COULOMB PASSIVE EARTH PRESSURE**

Pp = ½ Kp . . H2 Bina Nusantara

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**LATERAL EARTH PRESSURE DUE TO SURCHARGE**

Bina Nusantara

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**LATERAL EARTH PRESSURE DUE TO SURCHARGE**

Bina Nusantara

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**PURPOSE OF LATERAL EARTH PRESSURE**

STABILITY ANALYSIS GRAVITY WALL AGAINST SLIDING OVERTURNING Bina Nusantara

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**PURPOSE OF LATERAL EARTH PRESSURE**

Bina Nusantara

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**PURPOSE OF LATERAL EARTH PRESSURE**

Bina Nusantara

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SHEET PILE STRUCTURES SESSION 13 – 14 Bina Nusantara

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SHEET PILE Bina Nusantara

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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. Bina Nusantara

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**SHEET PILE TYPES (CANTILEVER)**

Bina Nusantara

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**SHEET PILE TYPES (ANCHORED)**

Free Earth Support Bina Nusantara

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**SHEET PILE TYPES (ANCHORED)**

Bina Nusantara Fixed Earth Support

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**SHEET PILE TYPES (ANCHORED)**

anchor plate or beam Bina Nusantara

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**SHEET PILE TYPES (ANCHORED)**

tie back vertical anchor pile Bina Nusantara

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**anchor beam with batter piles**

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

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**LATERAL EARTH PRESSURE DIAGRAM**

Bina Nusantara

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**LATERAL EARTH PRESSURE DIAGRAM**

Bina Nusantara

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**LATERAL EARTH PRESSURE DIAGRAM**

Fixed Earth Support Bina Nusantara

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**LATERAL EARTH PRESSURE DIAGRAM**

Free Earth Support Bina Nusantara

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**LATERAL EARTH PRESSURE DIAGRAM**

Free Earth Support Bina Nusantara

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**CALCULATION STEPS CANTILEVER SHEET PILE - SAND**

Bina Nusantara

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**CALCULATION STEPS CANTILEVER SHEET PILE - SAND**

1. Determine the value of Ka and Kp 2. Calculate p1and p2 with L1 and L2 are known 3. Calculate L3 4. Calculate the resultant of the area ACDE (P) 5. Determine the z (the center of pressure for the area ACDE) Bina Nusantara

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**CALCULATION STEPS CANTILEVER SHEET PILE - SAND**

6. Calculate p5 7. Calculate A1, A2, A3, A4 Bina Nusantara

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**CALCULATION STEPS CANTILEVER SHEET PILE - SAND**

8. Determine L4 9. Calculate p4 10. Calculate p3 11. Calculate L5 12. Draw the pressure distribution diagram 13. Obtain the theoretical depth ; D = L3 + L4 The actual depth of penetration is increased by about 20% - 30% 14. Calculate the maximum bending moment Bina Nusantara

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**EXAMPLE CANTILEVER SHEET PILE - SAND**

GWL d = 15.9 kN/m3 t = kN/m3 = 32o c = 0 kPa L1 = 2 m L2 = 3 m D Bina Nusantara Determine the penetration depth (D) and dimension of sheet pile

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**EXAMPLE CANTILEVER SHEET PILE - SAND**

Step 1 (determine the value of ka and kp) Step 2 (calculate p1 and p2) Step 3 (Calculate L3) kPa kPa m Bina Nusantara

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**EXAMPLE CANTILEVER SHEET PILE - SAND**

Step 4 (calculate P) Step 5 (calculate z) Step 6 (calculate p5) kN/m m kN/m2 Bina Nusantara

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**EXAMPLE CANTILEVER SHEET PILE - SAND**

Step 7 (calculate A1 – A4) Bina Nusantara

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**EXAMPLE CANTILEVER SHEET PILE - SAND**

Step 8 (determine L4) Step 9 (calculate p4) Step 10 (calculate p3) L4 4.8 m kPa kPa Bina Nusantara

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**EXAMPLE CANTILEVER SHEET PILE - SAND**

Step 11 (Calculate L5) Step 12 Draw the pressure distribution diagram Step 13 (the penetration dept of sheet pile) Theoretical = = 5.46 m Actual = 1.3 (L3+L4) =7.1 m m Bina Nusantara

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**EXAMPLE CANTILEVER SHEET PILE - SAND**

Bina Nusantara

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**EXAMPLE CANTILEVER SHEET PILE - SAND**

Dimension of Sheet Pile m kN.m Bina Nusantara

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SHEET PILE STRUCTURE SESSION 15 – 16 Bina Nusantara

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**CALCULATION STEPS CANTILEVER SHEET PILE - CLAY**

Bina Nusantara

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**CALCULATION STEPS CANTILEVER SHEET PILE - CLAY**

1. Determine the value of Ka and Kp In case of saturated soft clay with internal friction angle () = 0, we got Ka = Kp = 1 2. Calculate p1and p2 with L1 and L2 are known 3. Calculate the resultant of the area ACDE (P1) and z1 (the center of pressure for the area ACDE) Bina Nusantara

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**CALCULATION STEPS CANTILEVER SHEET PILE - CLAY**

4. Calculate the theoretical penetration depth of sheet pile (D) 5. Calculate L4 6. Calculate p6 and p7 7. Obtain the actual penetration depth of sheet pile Dactual = (1.4 – 1.6) x Dtheoretical Bina Nusantara

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**CALCULATION STEPS CANTILEVER SHEET PILE - CLAY**

8. Calculate the maximum bending moment Bina Nusantara

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**EXAMPLE CANTILEVER SHEET PILE - CLAY**

L1 = 2 m L2 = 3 m sand GWL d = 15.9 kN/m3 t = kN/m3 = 32o c = 0 kPa Clay D cu = 47 kPa = 0 o Bina Nusantara Determine the penetration depth (D) and dimension of sheet pile

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**EXAMPLE CANTILEVER SHEET PILE - CLAY**

Step 1 (Determine ka and kp) Step 2 (calculate p1 and p2) Step 3 (calculate P1 and z1) kPa kPa kN/m m Bina Nusantara

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**EXAMPLE CANTILEVER SHEET PILE - CLAY**

Step 4 (obtain Dtheoretical) Step 5 (calculate L4) D = 2.13 m L4 = 2.13 m Bina Nusantara

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**EXAMPLE CANTILEVER SHEET PILE - CLAY**

Step 6 (calculate p6 and p7) Step 7 (draw the lateral diagram) Step 8 (Obtain Dactual) kN/m2 Dactual = 1.5 x Dtheorical = 1.5 x 2.13 = 3.2 m Bina Nusantara

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**EXAMPLE CANTILEVER SHEET PILE - CLAY**

Calculation of moment Bina Nusantara

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**CALCULATION STEPS ANCHORED SHEET PILE – FREE – SAND**

Bina Nusantara

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**CALCULATION STEPS ANCHORED SHEET PILE – FREE – SAND**

1. Determine the value of Ka and Kp 2. Calculate p1and p2 with L1 and L2 are known 3. Calculate L3 4. Calculate P as a resultant of area ACDE 5. Determine the center of pressure for the area ACDE ( z ) Bina Nusantara

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**CALCULATION STEPS ANCHORED SHEET PILE – FREE – SAND**

6. Calculate L4 Determination of penetration depth of sheet pile (D) Dtheoretical = L3 + L4 Dactual = (1.3 – 1.4) Dtheoretical Determination of anchor force F = P – ½ [’(Kp – Ka)]L42 Bina Nusantara

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**CALCULATION STEPS ANCHORED SHEET PILE – FREE – CLAY**

Bina Nusantara

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**CALCULATION STEPS ANCHORED SHEET PILE – FREE – CLAY**

1. Determine the value of Ka and Kp In case of saturated soft clay with internal friction angle () = 0, we got Ka = Kp = 1 2. Calculate p1and p2 with L1 and L2 are known 3. Calculate the resultant of the area ACDE (P1) and z1 (the center of pressure for the area ACDE) Bina Nusantara

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**CALCULATION STEPS ANCHORED SHEET PILE – FREE – CLAY**

4. Calculate p6 5. Determination of penetration depth of sheet pile (D) p6.D2 + 2.p6.D.(L1+L2-l1) – 2.P1.(L1+L2-l1-z1) = 0 6. Determination of anchor force F = P1 – p6 . D Bina Nusantara

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**CALCULATION STEPS ANCHORED SHEET PILE – FIXED – SAND**

J Bina Nusantara

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**CALCULATION STEPS ANCHORED SHEET PILE – FIXED – SAND**

1. Determine the value of Ka and Kp 2. Calculate p1and p2 with L1 and L2 are known 3. Calculate L3 Bina Nusantara

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**CALCULATION STEPS ANCHORED SHEET PILE – FIXED – SAND**

4. determine L5 from the following curve (L1 and L2 are known) Bina Nusantara

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**CALCULATION STEPS ANCHORED SHEET PILE – FIXED – SAND**

5. Calculate the span of the equivalent beam as l2 + L2 + L5 = 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, Mmax, as WL’/8 Bina Nusantara

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**CALCULATION STEPS ANCHORED SHEET PILE – FIXED – SAND**

(moment of area ACDJI about O’) 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 I) Bina Nusantara

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