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Stress Distribution and all of its mysteries. I. The Bulb of Pressure Force.

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Presentation on theme: "Stress Distribution and all of its mysteries. I. The Bulb of Pressure Force."— Presentation transcript:

1 Stress Distribution and all of its mysteries

2 I. The Bulb of Pressure Force

3 I. The Bulb of Pressure “what are the stresses at this point?” Force

4 II. The Boussinesq Equation A. Goal: to determine the vertical and horizontal stresses under a point load in a homogeneous, isotropic medium. “Allows us to determine vertical and horizontal stresses at any point in space” (boo-sinn-esk)

5 II. The Boussinesq Equation B. The Equation:

6 Where v = Poisson’s Ratio (0.48)

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12 6.71

13 If Poisson’s ratio is ~0.5, equations simplify to: σx = 3Px 2 z 2π R 5 σy = 3Py 2 z 2π R 5

14 Your turn: Vertical load of 2500 lb/ft2 Determine horizontal and vertical stresses at X= 5, Y= 2, Z = 6

15 Borrow & Fill Computations

16 Cut and Fill Slopes FHWA, 2004

17 Proper OM & MD at time of compaction???

18 Photo: Rick Wooten ………………..Progressive Slope Failures

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26 Vol (ft 3 )Wt. (lbs/ft 3 ) VaAirWa VwWaterWw VsSoilWs Borrow Data: Wet density in situ = 106 lbs/ft3 Specific gravity = 2.70 Moisture Content = 15% Proctor Results: OM = 9% MD = 117 lbs/ft3 (dry) Vv Vt

27 Vol (ft 3 )Wt. (lbs/ft 3 ) VaAirWa VwWaterWw VsSoilWs Ws = Dry Density (lbs/ft3) = Wet Density (lbs/ft3) 1 + moisture content (decimal form) Borrow Data: Wet density in situ = 106 lbs/ft3 Specific gravity = 2.70 Moisture Content = 15% Proctor Results: OM = 9% MD = 117 lbs/ft3 (dry)

28 Vol (ft 3 )Wt. (lbs/ft 3 ) VaAirWa VwWaterWw VsSoilWs Ws = Dry Density (lbs/ft3) = Wet Density (lbs/ft3) 1 + moisture content (decimal form) Ws = Dry Density (lbs/ft3) = 106 lbs/ft 3 1 + 0.15 Borrow Data: Wet density in situ = 106 lbs/ft3 Specific gravity = 2.70 Moisture Content = 15% Proctor Results: OM = 9% MD = 117 lbs/ft3 (dry)

29 Vol (ft 3 )Wt. (lbs/ft 3 ) VaAirWa VwWaterWw VsSoil Ws 92 Ws = Dry Density (lbs/ft3) = Wet Density (lbs/ft3) 1 + moisture content (decimal form) Ws = Dry Density (lbs/ft3) = 106 lbs/ft 3 1 + 0.15 Ws = 92 lbs/ft 3 Borrow Data: Wet density in situ = 106 lbs/ft3 Specific gravity = 2.70 Moisture Content = 15% Proctor Results: OM = 9% MD = 117 lbs/ft3 (dry)

30 Vol (ft 3 )Wt. (lbs/ft 3 ) VaAirWa VwWaterWw VsSoil Ws 92 Moisture Content = weight of water *100 weight of soil Ws = Dry Density (lbs/ft3) = Wet Density (lbs/ft3) 1 + moisture content (decimal form) Ws = Dry Density (lbs/ft3) = 106 lbs/ft 3 1 + 0.15 Ws = 92 lbs/ft 3 Borrow Data: Wet density in situ = 106 lbs/ft3 Specific gravity = 2.70 Moisture Content = 15% Proctor Results: OM = 9% MD = 117 lbs/ft3 (dry)

31 Vol (ft 3 )Wt. (lbs/ft 3 ) VaAirWa VwWaterWw VsSoil Ws 92 Moisture Content = weight of water *100 weight of dry soil 15 = Ww *100 92 lbs/ft 3 Ws = Dry Density (lbs/ft3) = Wet Density (lbs/ft3) 1 + moisture content (decimal form) Ws = Dry Density (lbs/ft3) = 106 lbs/ft 3 1 + 0.15 Ws = 92 lbs/ft 3 Borrow Data: Wet density in situ = 106 lbs/ft3 Specific gravity = 2.70 Moisture Content = 15% Proctor Results: OM = 9% MD = 117 lbs/ft3 (dry)

32 Vol (ft 3 )Wt. (lbs/ft 3 ) VaAirWa VwWater Ww 14 VsSoil Ws 92 Moisture Content = weight of water *100 weight of soil 15 = Ww *100 92 lbs/ft 3 Ww = 14 lbs/ft3 Ws = Dry Density (lbs/ft3) = Wet Density (lbs/ft3) 1 + moisture content (decimal form) Ws = Dry Density (lbs/ft3) = 106 lbs/ft 3 1 + 0.15 Ws = 92 lbs/ft 3 Borrow Data: Wet density in situ = 106 lbs/ft3 Specific gravity = 2.70 Moisture Content = 15% Proctor Results: OM = 9% MD = 117 lbs/ft3 (dry)

33 Vol (ft 3 )Wt. (lbs/ft 3 ) VaAir Wa 0 VwWater Ww 14 VsSoil Ws 92 Specific Gravity (Gs) = 2.70 (unitless) Unit Weight water (γ w ) = 62.4 lbs per ft 3

34 Vol (ft 3 )Wt. (lbs/ft 3 ) VaAir Wa 0 VwWater Ww 14 VsSoil Ws 92 Specific Gravity (Gs) = 2.70 (unitless) Unit Weight water (γ w ) = 62.4 lbs per ft 3 Vol Soil (Vs) = Ws Gs * γw

35 Vol (ft 3 )Wt. (lbs/ft 3 ) VaAir Wa 0 VwWater Ww 14 Vs 0.55 Soil Ws 92 Specific Gravity (Gs) = 2.70 (unitless) Unit Weight water (γ w ) = 62.4 lbs per ft 3 Vol Soil (Vs) = Ws= 92 lbs/ft3 Gs * γw (2.70)*(62.4 lbs)

36 Vol (ft 3 )Wt. (lbs/ft 3 ) VaAir Wa 0 VwWater Ww 14 Vs 0.55 Soil Ws 92 Specific Gravity (Gs) = 2.70 (unitless) Unit Weight water (γ w ) = 62.4 lbs per ft 3 Vol Soil (Vs) = Ws= 92 lbs/ft3 Gs * γw (2.70)*(62.4 lbs) Vs = 0.55 ft3

37 Vol (ft 3 )Wt. (lbs/ft 3 ) VaAir Wa 0 VwWater Ww 14 Vs 0.55 Soil Ws 92 Specific Gravity (Gs) = 2.70 (unitless) Unit Weight water (γ w ) = 62.4 lbs per ft 3 Vol Soil (Vs) = Ws= 92 lbs/ft3 Gs * γw (2.70)*(62.4 lbs) Vs = 0.55 ft3 Vol Voids (Vv) = Vt - Vs

38 Vol (ft 3 )Wt. (lbs/ft 3 ) VaAir Wa 0 VwWater Ww 14 Vs 0.55 Soil Ws 92 Specific Gravity (Gs) = 2.70 (unitless) Unit Weight water (γ w ) = 62.4 lbs per ft 3 Vol Soil (Vs) = Ws= 92 lbs/ft3 Gs * γw (2.70)*(62.4 lbs) Vs = 0.55 ft3 Vol Voids (Vv) = Vt - Vs Vv = 1 – 0.55 Vv = 0.45 ft3 (we will use this value later…)

39 Vol (ft 3 )Wt. (lbs/ft 3 ) VaAir Wa 0 VwWater Ww 14 Vs 0.55 Soil Ws 92 Specific Gravity (Gs) = 2.70 (unitless) Unit Weight water (γ w ) = 62.4 lbs per ft 3 Vv = 0.45 ft3 Vw = Ww = 14 lbs/ft3 γ w 62.4 lbs

40 Vol (ft 3 )Wt. (lbs/ft 3 ) VaAir Wa 0 Vw 0.22 Water Ww 14 Vs 0.55 Soil Ws 92 Specific Gravity (Gs) = 2.70 (unitless) Unit Weight water (γ w ) = 62.4 lbs per ft 3 Vw = Ww = 14 lbs/ft3 γ w 62.4 lbs Vw = 0.22 ft3

41 Vol (ft 3 )Wt. (lbs/ft 3 ) VaAir Wa 0 Vw 0.22 Water Ww 14 Vs 0.55 Soil Ws 92 Specific Gravity (Gs) = 2.70 (unitless) Unit Weight water (γ w ) = 62.4 lbs per ft 3 Vv = 0.45 ft3 Vol Air = Va = Vv – Vw

42 Vol (ft 3 )Wt. (lbs/ft 3 ) VaAir Wa 0 Vw 0.22 Water Ww 14 Vs 0.55 Soil Ws 92 Specific Gravity (Gs) = 2.70 (unitless) Unit Weight water (γ w ) = 62.4 lbs per ft 3 Vv = 0.45 ft3 Vol Air = Va = Vv – Vw Va = 0.45 – 0.22

43 Vol (ft 3 )Wt. (lbs/ft 3 ) Va 0.23 Air Wa 0 Vw 0.22 Water Ww 14 Vs 0.55 Soil Ws 92 Specific Gravity (Gs) = 2.70 (unitless) Unit Weight water (γ w ) = 62.4 lbs per ft 3 Vol Air = Va = Vv – Vw Va = 0.45 – 0.22 Va = 0.23 ft3

44 Vol (ft 3 )Wt. (lbs/ft 3 ) Va 0.23 Air Wa 0 Vw 0.22 Water Ww 14 Vs 0.55 Soil Ws 92 Specific Gravity (Gs) = 2.70 (unitless) Unit Weight water (γ w ) = 62.4 lbs per ft 3 Vv = 0.45 ft3 Void Ratio (e) = Vv Vs

45 Vol (ft 3 )Wt. (lbs/ft 3 ) Va 0.23 Air Wa 0 Vw 0.22 Water Ww 14 Vs 0.55 Soil Ws 92 Specific Gravity (Gs) = 2.70 (unitless) Unit Weight water (γ w ) = 62.4 lbs per ft 3 Void Ratio (e) = Vv Vs = 0.45 0.55

46 Vol (ft 3 )Wt. (lbs/ft 3 ) Va 0.23 Air Wa 0 Vw 0.22 Water Ww 14 Vs 0.55 Soil Ws 92 Specific Gravity (Gs) = 2.70 (unitless) Unit Weight water (γ w ) = 62.4 lbs per ft 3 Void Ratio (e) = Vv Vs = 0.45 0.55 e = 0.82

47 Vol (ft 3 )Wt. (lbs/ft 3 ) VaAirWa VwWaterWw VsSoilWs Fill Data: Wet density in situ = 106 lbs/ft3 Specific gravity = 2.70 Moisture Content = 15% Specific Gravity = 2.7 Proctor Results: OM = 9% MD = 117 lbs/ft3 (dry) Vv Vt

48 Vol (ft 3 )Wt. (lbs/ft 3 ) VaAirWa VwWaterWw VsSoilWs Fill Data: Wet density in situ = 106 lbs/ft3 Specific gravity = 2.70 Moisture Content = 15% Specific Gravity = 2.7 Proctor Results: OM = 9% MD = 117 lbs/ft3 (dry) Vv Vt Moisture Content = weight of water *100 weight of soil

49 Vol (ft 3 )Wt. (lbs/ft 3 ) VaAirWa VwWaterWw VsSoilWs Fill Data: Wet density in situ = 106 lbs/ft3 Specific gravity = 2.70 Moisture Content = 15% Specific Gravity = 2.7 Proctor Results: OM = 9% MD = 117 lbs/ft3 (dry) Vv Vt Moisture Content = weight of water *100 weight of soil 9 = Ww *100 117 lbs/ft3

50 Vol (ft 3 )Wt. (lbs/ft 3 ) VaAirWa VwWater Ww 10.5 VsSoilWs Fill Data: Wet density in situ = 106 lbs/ft3 Specific gravity = 2.70 Moisture Content = 15% Specific Gravity = 2.7 Proctor Results: OM = 9% MD = 117 lbs/ft3 (dry) Vv Vt Moisture Content = weight of water *100 weight of soil 9 = Ww *100 117 lbs/ft3 Ww = 10.5 lbs/ft3

51 Vol (ft 3 )Wt. (lbs/ft 3 ) VaAirWa VwWater Ww 10.5 VsSoil Ws 117 Fill Data: Wet density in situ = 106 lbs/ft3 Specific gravity = 2.70 Moisture Content = 15% Specific Gravity = 2.7 Proctor Results: OM = 9% MD = 117 lbs/ft3 (dry) Vv Vt Ws = Dry Density (lbs/ft3) = MD = 117 lbs/ft3

52 Vol (ft 3 )Wt. (lbs/ft 3 ) VaAir Wa 0 VwWater Ww 10.5 VsSoil Ws 117 Fill Data: Wet density in situ = 106 lbs/ft3 Specific gravity = 2.70 Moisture Content = 15% Specific Gravity = 2.7 Proctor Results: OM = 9% MD = 117 lbs/ft3 (dry) Vv Vt Ws = Dry Density (lbs/ft3) = MD = 117 lbs/ft3

53 Fill Data: Wet density in situ = 106 lbs/ft3 Specific gravity = 2.70 Moisture Content = 15% Specific Gravity = 2.7 Proctor Results: OM = 9% MD = 117 lbs/ft3 (dry) Vv Vt Vol Soil (Vs) = Ws= 117 lbs/ft3 Gs * γw (2.70)*(62.4 lbs) Vol (ft 3 )Wt. (lbs/ft 3 ) VaAir Wa 0 VwWater Ww 10.5 VsSoil Ws 117

54 Fill Data: Wet density in situ = 106 lbs/ft3 Specific gravity = 2.70 Moisture Content = 15% Specific Gravity = 2.7 Proctor Results: OM = 9% MD = 117 lbs/ft3 (dry) Vv Vt Vol Soil (Vs) = Ws= 117 lbs/ft3 Gs * γw (2.70)*(62.4 lbs) Vs = 0.69 ft3 (compared to 0.55 from the borrow source) Vol (ft 3 )Wt. (lbs/ft 3 ) VaAir Wa 0 VwWater Ww 10.5 Vs 0.69 Soil Ws 117

55 Fill Data: Wet density in situ = 106 lbs/ft3 Specific gravity = 2.70 Moisture Content = 15% Specific Gravity = 2.7 Proctor Results: OM = 9% MD = 117 lbs/ft3 (dry) Vv Vt Vol (ft 3 )Wt. (lbs/ft 3 ) VaAir Wa 0 VwWater Ww 10.5 Vs 0.69 Soil Ws 117 Vol Voids (Vv) = Vt - Vs

56 Fill Data: Wet density in situ = 106 lbs/ft3 Specific gravity = 2.70 Moisture Content = 15% Specific Gravity = 2.7 Proctor Results: OM = 9% MD = 117 lbs/ft3 (dry) Vv Vt Vol (ft 3 )Wt. (lbs/ft 3 ) VaAir Wa 0 VwWater Ww 10.5 Vs 0.69 Soil Ws 117 Vol Voids (Vv) = Vt - Vs Vv = 1 – 0.69 Vv = 0.31 ft3

57 Fill Data: Wet density in situ = 106 lbs/ft3 Specific gravity = 2.70 Moisture Content = 15% Specific Gravity = 2.7 Proctor Results: OM = 9% MD = 117 lbs/ft3 (dry) Vv Vt Vol (ft 3 )Wt. (lbs/ft 3 ) VaAir Wa 0 VwWater Ww 10.5 Vs 0.69 Soil Ws 117 Vw = Ww = 10.5 lbs/ft3 γ w 62.4 lbs

58 Fill Data: Wet density in situ = 106 lbs/ft3 Specific gravity = 2.70 Moisture Content = 15% Specific Gravity = 2.7 Proctor Results: OM = 9% MD = 117 lbs/ft3 (dry) Vv Vt Vol (ft 3 )Wt. (lbs/ft 3 ) VaAir Wa 0 Vw 0.17 Water Ww 10.5 Vs 0.69 Soil Ws 117 Vw = Ww = 10.5 lbs/ft3 γ w 62.4 lbs Vw = 0.17

59 Fill Data: Wet density in situ = 106 lbs/ft3 Specific gravity = 2.70 Moisture Content = 15% Specific Gravity = 2.7 Proctor Results: OM = 9% MD = 117 lbs/ft3 (dry) Volume of voids = 0.31 Vv Vt Vol (ft 3 )Wt. (lbs/ft 3 ) VaAir Wa 0 Vw 0.17 Water Ww 10.5 Vs 0.69 Soil Ws 117 Vol Air = Va = Vv – Vw Va = 0.31 – 0.17

60 Fill Data: Wet density in situ = 106 lbs/ft3 Specific gravity = 2.70 Moisture Content = 15% Specific Gravity = 2.7 Proctor Results: OM = 9% MD = 117 lbs/ft3 (dry) Vv Vt Vol (ft 3 )Wt. (lbs/ft 3 ) Va 0.14 Air Wa 0 Vw 0.17 Water Ww 10.5 Vs 0.69 Soil Ws 117 Vol Air = Va = Vv – Vw Va = 0.31 – 0.17 Va = 0.14 ft3

61 Fill Data: Wet density in situ = 106 lbs/ft3 Specific gravity = 2.70 Moisture Content = 15% Specific Gravity = 2.7 Proctor Results: OM = 9% MD = 117 lbs/ft3 (dry) Vv Vt Vol (ft 3 )Wt. (lbs/ft 3 ) Va 0.14 Air Wa 0 Vw 0.17 Water Ww 10.5 Vs 0.69 Soil Ws 117 Void Ratio (e) = Vv Vs

62 Fill Data: Wet density in situ = 106 lbs/ft3 Specific gravity = 2.70 Moisture Content = 15% Specific Gravity = 2.7 Proctor Results: OM = 9% MD = 117 lbs/ft3 (dry) Vv Vt Vol (ft 3 )Wt. (lbs/ft 3 ) Va 0.14 Air Wa 0 Vw 0.17 Water Ww 10.5 Vs 0.69 Soil Ws 117 Void Ratio (e) = Vv Vs = 0.31 0.69 e = 0.45

63 Vol (ft 3 )Wt. (lbs/ft 3 ) Va 0.14 Air Wa 0 Vw 0.17 Water Ww 10.5 Vs 0.69 Soil Ws 117 Vol (ft 3 )Wt. (lbs/ft 3 ) Va 0.23 Air Wa 0 Vw 0.22 Water Ww 14 Vs 0.55 Soil Ws 92 BORROW DATA FILL DATA

64 The Answer: How much borrow material is needed?

65 The Answer: Volume of Borrow = 1 + e borrow Volume of Fill 1 + e fill

66 The Answer: Volume of Borrow = 1 + e borrow Volume of Fill 1 + e fill Volume of Borrow = 1 + 0.82 50,000 yd 3 1 + 0.45

67 The Answer: Volume of Borrow = 1 + e borrow Volume of Fill 1 + e fill Volume of Borrow = 1 + 0.82 50,000 yd 3 1 + 0.45 Volume of Borrow = 62,759 yd 3


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