Principles of Foundation Engineering (MindTap Course List)
9th Edition
ISBN: 9781337705028
Author: Braja M. Das, Nagaratnam Sivakugan
Publisher: Cengage Learning
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Chapter 18, Problem 18.7P
a.
To determine
Find the required depth to drive a sheet pile to carry out an excavation to 4m depth.
b.
To determine
Find the maximum bending moment in the sheet pile and the required section modulus for the sheet pile section.
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Students have asked these similar questions
6.5 The sides of an excavation 3.0m deep in sand are to be supported by a cantilever
sheet pile wall. The water table is 1.5 m below the bottom of the excavation. The
sand has a saturated unit weight of 20 kN/m³, a unit weight above the water table
of 17 kN/m³ and the characteristic value of o' is 36°. Using the traditional method,
determine the required depth of embedment of the piling below the bottom of the
excavation to give a factor of safety of 2.0 with respect to passive resistance.
M
Figure below shows the cross-section of an excavation which is to be made alongside a
river. Write down an expression for the effective stress at level A-A and use this to establish the depth H to
which the water in the trench can be reduced before instability occurs (when o'z is zero). The shear
resistance at the clay and sheet pile interface can be considered negligible.
sheet piling
River
peaty silt
3.5 m
dredge level
8 m
. alluvial
silty clay
6.0 m
(y 18 kN/m³)
3 m
coarse
3.5 m
gravel
impervious red marl
When a vertical face excavation was made in a
clayey silt, having density of 20 kN/m³, it failed at
a depth of excavation of 4 m. What is the cohesive
strength (in kN/m²) of the soil, if its angle of internal
friction was 30°?
Chapter 18 Solutions
Principles of Foundation Engineering (MindTap Course List)
Ch. 18 - Refer to Figure 18.9. A cantilever sheet pile is...Ch. 18 - Prob. 18.2PCh. 18 - Prob. 18.3PCh. 18 - Refer to Figure 18.13. Given L1 = 1.5 m, L2 = 3 m;...Ch. 18 - In Problem 18.4, find the maximum bending moment...Ch. 18 - Prob. 18.6PCh. 18 - Prob. 18.7PCh. 18 - Prob. 18.8PCh. 18 - Refer to Figure 18.23. Given L1=3m, L2=6m,...Ch. 18 - Prob. 18.10P
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- The water table at a site is at 5 m below the ground level, and it is required to excavate to this level. The soil profile consists of a thick bed of sand where the unit weight is m = 17.0 kN/m3 above the water table and sat = 20.0 kN/m3 below the water table. The friction angle of the sand is 37. The wall of the excavation will be supported by cantilever sheet piles. How deep would you drive the sheet piles? Use the simplified analysis (Figure 15.37) with a factor of safety of 1.5 on the passive resistance. Determine the maximum bending moment in the sheet pile and the required section modulus for the sheet pile section (given an allowable stress of 190 MN/m2).arrow_forwardA vertical sheet pile supports a horizontal backfill having a height of 6 m. The backfill has a unit weight of 19 KN/m² and an angle of internal friction of 30°. Determine the required depth of penetration. A 3 m B 4m 4.5 m D 5.5 marrow_forwardQuestion 3 A new underground tunnel section is designed by a geotechnical consultant. For the underground station a 5 m wide braced excavation is made in a saturated clay as shown in Figure Q3 with unit weight, y = 18.5 kN/m², friction angle, o = 0° and cohesion, c = 20 kN/m?. The struts are spaced at 5 m center to center in plan. Refer Appendix 1 to select the sheet-pile section. i. Draw the strut forces. ii. Determine the section modulus of the sheet pile needed. Assume oall = 170 MN/m? iii. Determine the maximum moment for the wales at levels B and C. Show a complete answer, including all numerical values and necessary diagrams. 5 m 3 m B 2 marrow_forward
- The excavation shown below will be made on the clay for the construction of a highway. Potential Slope stability analysis is required on the slip plane. The ground is silty clay and c '= 18 kPa,' '= 20o and water = 100 kPa. At point a If the shear stress is 60 kPa, calculate the safety coefficient for this point.arrow_forwardSolve as quick as possible A pit of 6.4 m deep is to be excavated in a fine sand stratum completely saturated up to the ground surface. The saturated unit weight of the sand was obtained as 20.3 kN/m³. To stabilize the bottom of the excavation (prevent boiling), it was decided to drive steel sheet piles to act as cutoff walls that encircle the excavation. Determine the total length of sheet pile wall to provide a factor of safety of 1.5 against sand boiling. Assume specific gravity of soil, G, = 2.7 and unit weight of water, Y-9.81 kN/m².arrow_forwardQuestion 3 The flownet for an excavation supported by sheet pile walls is shown in Figure Q3. The soil being excavated is a uniform fine sand with a coefficient of permeability (k) of 5×104 m/s. The width of the trench is 5 m, with a length of 50 m. A constant external water level of 2 m is maintained at the ground level. Ground level 2m 6m 6m 6m ▼ K Line of symmetry- 5m Sheet pile wall 9m (c) Determine the pore water pressure (u) at Point A. Figure Q3 (a) Explain the physical significance of a flownet. In other words, explain what these lines represent. (b) Determine the total water flow rate (Q) at the excavation floor. K (d) If the excavation was carried out on the Moon, determine the total water flow rate (Q) at the excavation floor again (assuming that the gravitational acceleration on the Moon is 1.6 m/s²).arrow_forward
- Q=400KN Ground Level 38° #16KN.m3 K=0.90 tan-0.45 N=80 5m Dense Sand 38° Tar=18.5kN.m3 4m Saturated Sand 39° c=150kN.m2 -20.2kN.m Bed Rock Not to scale (a) Design a pile foundation. (b) Design a shallow square foundation. (c) Compare the two foundations designed in (a) and (b).arrow_forwardA 600mm diameter pile is embedded in 3 layers of dense sand at a depth of 17m. Nq = 86. The groundwater table is situated between Layers 2 and 3. The layers have the following properties: Layer 1: γ = 16.9 kN/m3. 3m thick. Layer 2: γ = 17.6 kN/m3. 5.5m thick. Layer 3: γsat = 19.65 kN/m3. K is 0.9 and tan α = 0.37. The factor of safety is 3.0. What is the skin friction resistance of the pile in kN? What is the skin friction resistance of the pile in kN? None of the choices 1684.170 1477.156 1257.150 1322.744 866.118 Please answer this asap. For upvote. Thank you very mucharrow_forwardA 600mm diameter pile is embedded in 3 layers of dense sand at a depth of 17m. Nq = 86. The groundwater table is situated between Layers 2 and 3. The layers have the following properties: Layer 1: γ = 16.9 kN/m3. 3m thick. Layer 2: γ = 17.6 kN/m3. 5.5m thick. Layer 3: γsat = 19.65 kN/m3. K is 0.9 and tan α = 0.37. The factor of safety is 3.0. What is the allowable axial load capacity of the pile in kN? 5476.785 1750.169 1127.606 2439.011 None of the choices 2365.846 Please answer this asap. For upvote. Thank you very mucharrow_forward
- A proposed building is to have three levels of underground parking, as shown in the figure below. To construct this building, it will be necessary to make a 10.0 m excavation, which will need to be temporarily dewatered. The natural and dewatered groundwater tables are shown, and the medium clay is normally consolidated. The dewatering of the area under the existing building caused an increase in vertical effective stress. - 28 m - Existing building A B Proposed 1.5 m building Natural y. Dewatered y = 19.5 kN/mª 5 m 1.51 8.5 m 10 m 12.5 m Sand- (assume imcompressible) 2.5 m Fy= 20:0 kN/m. Medium clay C(1+ eo) = 0.26 y = 16.5 kN/m³ 10.3 m Stiff soils (assume imcompressible) Unit weight of SAND above the water table is 19.5 KN/cum while that below the water table is 20 KN/cuM. The unit weight of CLAY is 16.5 KN/cyM. The chief engineer is concerned that this dewatering operation may cause excessive settlement in the adjacent building and has asked you to: Compute for the anticipated…arrow_forwardCircular precast concrete piles with 60 cm in diameter will be driven to a tip penetration of 30 m. The soil profile is all clay and the water table is 2 m under the ground surface. Consider that the soils with cu < 60 kPa can be considered soft for this case. The unit weight of water is 10 kN/m3. Unconfined compression tests on samples taken from a thin-walled Shelby tubes were performed, and the soil profile has the following stratification: 0-5 m cu= 20 kPa γt=16.5 kN/m3 5-15 m cu= 40 kPa γt=17.5 kN/m3 15-80 m cu= 200 kPa γt=20.5 kN/m3 State any necessary assumptions. Show a summary table comparing the different capacities and discuss reasons for differences. a. Tomlinson's 1957 a method (alpha method #1) b. Tomlinson's 1971 a method (alpha method #2) a. Original λ method (lambda method #1) b. Revised λ method based on pile length (lambda method #2) c. API method (Randolph and Murphy 1985)arrow_forward1. Figure 3 shows a cantilever sheet pile wall, determine the: Sand 3 m y = 16 kN/m3 O' = 30 %3! Sand Ysat = 19 kN/m3 O' = 30 6 m Clay Ysat = 19 kN/m3 Cu = 54 kPa D %3D Figure 3 (a) Theoretical depth of embedment,arrow_forward
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