Refer to Problem 9.6. It is required to make an open excavation of 18 ft in the saturated clay. To avoid heaving, the cut will be filled with water similar to that shown in Figure 9.6. What should be the height of water, h, in the excavation?
> Figure 12.42 shows a soil profile. The uniformly distributed load on the ground surface is Ds. Given:  = 1000 lb/ft2 , H1 = 8 ft, H2 = 15 ft, and H3 = 17 ft. Also, Sand: dry = 110 lb/ft3 , ï
> The results of a laboratory consolidation test on a clay specimen are the following. Given the initial height of specimen 5 0.748 in., Gs = 2.68, mass of dry specimen = 95.2 g, and area of specimen = 4.91 in2: Plot the e-log â&
> Refer to Problem 3.16. Determine the weight of water, in lb, that will be in 2.5 ft3 of the soil when saturated.
> Repeat Problem 12.2 using the following values
> Foundation engineers are often challenged by the existence of soft compressible soils at the construction site. Figure 12.44 shows a soil profile with a silty sand ( = 17 kN/m3 ; sat = 19.2 kN/m3 ) underlain by high pl
> The following are the results of a consolidation test. Plot the e-log ’ curve. Using Casagrande’s method, determine the preconsolidation pressure. Calculate the compression index, Cc, from the lab
> Refer to Figure 12.43. Given that B = 1 m, L = 3 m, and Q = 110 kN, calculate the primary consolidation settlement of the foundation.
> A normally consolidated clay layer is 3 m thick (one-way drainage). From the application of a given pressure, the total anticipated primary consolidation settlement will be 80 mm. What is the average degree of consolidation for the clay layer when the se
> A 3 m thick layer of saturated clay (two-way drainage) under a surcharge loading underwent 90% primary consolidation in 100 days. The laboratory test’s specimen will have two-way drainage. Find the coefficient of consolidation of clay for the pressure r
> The time for 50% consolidation of a 25 mm thick clay layer (drained at top and bottom) in the laboratory is 225 s. How long (in days) will it take for a 2 m thick layer of the same clay in the field (under the same pressure increment) to reach 50% consol
> For a laboratory consolidation test on a clay specimen (drained on both sides), the following were obtained. Thickness of the clay layer = 25 mm ’ 1 = 200 kN/m2 e1 = 0.73 ’ 2 = 400 kN/m2 e2 = 0.61 Time for 50% consolidation (t50) = 2.8 min Determi
> For a normally consolidated clay, the following are given. ’ o = 2 ton/ft2 e = eo = 1.21 ’ o + ’ = 4 ton/ft2 e = 0.96 The hydraulic conductivity k of the clay for the preceding loading range is 1.8 3 1024 ft/day. How long (in days) will it ta
> The time for 50% consolidation of a 1 in. thick clay layer (drained at top and bottom) in the laboratory is 2 min, 20 s. How long (in days) will it take for an 8 ft thick layer of the same clay in the field (under the same pressure increment) to reach 30
> The moist unit weights and degrees of saturation of a soil are given in the table. Determine: e Gs
> The coordinates of two points on a virgin compression curve are as follows. e1 = 1.7 ’ 1 = 150 kN/m2 e2 = 1.48 ’ 2 = 400 kN/m2 Determine the coefficient of volume compressibility for the pressure range stated. Given that cv = 0.002 cm2 /s, dete
> Following are the relationships of e and ’for a clay soil. For this clay soil in the field, the following values are given: H = 4.5 ft, ’ o = 0.7 ton/ft2 , and &a
> Refer to Problem 12.6. Given: cv = 2.8 × 10– 6 m2 /min. How long will it take for 60% consolidation to occur?
> Following are the results of a laboratory consolidation test on a sample of undisturbed clay obtained from the field The height of the specimen at the beginning of the test was 1.9 cm, and the diameter was 6.35 cm. The mass of the dry specimen was 91 g
> A shallow foundation supported by a silty sand is shown in Figure 11.6. Given: Length: L = 3 m Width: B = 3 m Depth of foundation: Df = 1.5 m Thickness of foundation: t = 0.25 m Load per unit area: = 150 kN/m2 Ef = 15 3 106 kN/m2 The silty sand has t
> A rigid, reinforced concrete foundation is subjected to a column load of 87,000 lb. The foundation plan measures 8 ft × 8 ft and rests on 21 ft (5 H’) of layered soil underlain by rock. The soil layers have the following ch
> A vertical column load, P = 600 kN, is applied to a rigid concrete foundation with dimensions B = 1 m and L = 2 m, as shown in Figure 11.11. The foundation rests at a depth Df = 0.75 m on a uniform dense sand with the following properties. Average modulu
> Repeat Problem 10.8 with the following data. q1 = 300 kN/m x1 = 4 m q2 = 260 kN/m x2 = 3 m z = 3 m
> Refer to Figure 10.50. Determine the vertical stress increase, s, at point A with the following values. q1 = 75 kN/m x1 = 2 m q2 = 300 kN/m x2 = 3 m z = 2 m
> Point loads of magnitude 8.9, 17.8, and 26.7 kN act at A, B, and C, respectively (Figure 10.49). Determine the increase in vertical stress at a depth of 3 m below point D. Use Boussinesq’s equation.
> The moist unit weight of a soil is 112.32 lb/ft3 at a moisture content of 10%. Given Gs = 2.7, determine: e Saturated unit weight Answer / /
> Repeat Problem 10.5 for the soil element shown in Figure 10.48.
> A soil element is shown in Figures 10.47. Determine the following. Maximum and minimum principal stresses Normal and shear stresses on the plane AB Use the pole method.
> Repeat Problem 10.3 for the soil element shown in Figure 10.46.
> Using the principles of Mohr’s circles for the soil element shown in Figure 10.45, determine the following. Maximum and minimum principal stresses Normal and shear stresses on the plane AB
> Refer to Figure 10.57. For the linearly increasing vertical loading on an infinite strip of width 5 m, determine the vertical stress increase, z, at A.
> Refer to Figure 10.56. If R = 4 m and hw = height of water = 5 m, determine the vertical stress increases 2 m below the loaded area at radial distances where r = 0, 2, 4, 6, and 8 m.
> Figure 10.56 shows the schematic of a circular water storage facility resting on the ground surface. The radius of the storage tank is R = 2.5 m and the maximum height of water is hw = 4 m. Determine the vertical stress increase, ï
> Refer to the flexible loaded rectangular area shown in Figure 10.55. Using Eq. (10.42), determine the vertical stress increase below the center of the area at a depth of 3.5 m.
> Repeat Problem 10.1 for the element shown in Figure 10.44.
> The plan of a flexible rectangular loaded area is shown in Figure 10.55. The uniformly distributed load on the flexible area, a, is 100 kN/m2 . Determine the increase in the vertical stress, z, at a depth of z = 2 m be
> A soil has w = 18.2%, Gs =2.67, and S =80%. Determine the moist and dry unit weights of the soil in lb/ft3.
> Refer to Figure 10.54. The circular flexible area is uniformly loaded. Given q = 300 kN/m2 and using Newmark’s chart, determine the vertical stress increase z at point A.
> Figure 10.31 shows a flexible circular area of radius R = 3 m. The uniformly distributed load on the circular area is 96 kN/m2. Calculate the vertical stress increase at r = 0, 0.6, 1.2, 2.4, and 3.6 with z = 1.5 m.
> Consider a circularly loaded flexible area on the ground surface. Given the radius of the circular area R = 4 m and the uniformly distributed load q = 200 kN/m2 , calculate the vertical stress increase, z, at points 1.5, 3, 6, 9, and 12 m below the gro
> Figure 10.53 shows an embankment load for a silty clay soil layer. Determine the vertical stress increase at points A, B, and C.
> An earth embankment diagram is shown in Figure 10.52. Determine the stress increase at point A due to the embankment load.
> Repeat Problem 10.12 for B = 3 m, q = 60 kN/m2, x = 1.5 m, and z = 3 m.
> Refer to Figure 10.17. Given: B = 3.7 m q = 16.8 kN/m2 x = 2.7 m z = 1.5 m. Determine the vertical stress increase, z, at Point A.
> Refer to Figure 10.51. Due to the application of line loads q1 and q2, the vertical stress increase, z, at A is 30 kN/m2. Determine the magnitude of q2.
> Refer to Figure 10.50. Given: q1 = 10.9 kN/m x1 = 2.45 m x2 = 1.22 m z = 0.9 m If the vertical stress at point A due to the loading is 1.7 kN/m2, determine the magnitude of q2.
> A soil element is shown in Figure 10.43. Determine the following. Maximum and minimum principal stresses Normal and shear stresses on the plane AB Use Eqs. (10.3), (10.4), (10.6), and (10.7).
> A soil has e = 0.75, w = 21.5%, and Gs = 2.71. Determine: Moist unit weight (lb/ft3) Dry unit weight (lb/ft3) Degree of saturation (%)
> Refer to Figure 9.5a. Given: H1 = 1 m, H2 = 2 m, h = 1.2 m, void ratio of sand (e) = 0.55, specific gravity of soil solids (Gs) = 2.68, area of the tank = 0.5 m2 , and hydraulic conductivity of sand = 0.1 cm/s. What is the rate of upward seepage? If h 5
> Refer to Figure 9.5a. If H1 = 0.6 m, H2 = 1 m, h 5 0.4 m, sat = 18.6 kN/m3 , hydraulic conductivity of sand (k) = 0.12 cm/s, and area of tank = 0.45 m2 , what is the rate of upward seepage of the water (m3 /min)?
> An exploratory drill hole was made in a stiff saturated clay (see Figure 9.28). The sand underlying the clay was observed to be under artesian pressure. Water in the drill hole rose to a height of 18 ft above the top of the sand layer. If an open excavat
> A sand has Gs = 2.68. Calculate the hydraulic gradient that will cause boiling for e = 0.4, 0.5, 0.6, and 0.7. Plot a graph for icr versus e.
> Refer to the soil profile shown in Figure 9.27. Calculate the variation of , u, and ’ with depth. If the water table rises to the top of the ground surface, what is the change in the effective stres
> Refer to Figure 9.26. Calculate , u, and ’ at A, B, C, and D for the following cases, and plot the variations with depth. (Note: e = void ratio,  = moisture content, Gs = specific
> Refer to Figure 9.26. Calculate , u, and ’ at A, B, C, and D for the following cases, and plot the variations with depth. (Note: e = void ratio,  = moisture content, Gs = specific
> Figure 9.31 shows a concrete dam. Consider Case 1 without the sheet pile and Case 2 with the sheet pile along the upstream side. Draw flow nets for both cases. Determine the value of q/k for both cases. (Note: q= m3/s/m; k = m/s.) Determine the factor of
> Determine the factor of safety against heave on the downstream side of the single-row sheet pile structure shown in Figure 9.30. Use the following soil and design parameters: H1 = 7 m, H2 = 3 m, thickness of permeable layer (T) = 12 m, design depth of pe
> Results of a sieve analysis for Soils A, B, and C are given below. To obtain a more representative sample for further geotechnical testing, a ternary blend was created by uniformly mixing 8000 kg of each soil. If a sieve analysis is conducted on the mi
> Repeat Problem 2.3 with the following data.
> Design a clamper to perform the function indicated in Fig. 2.184.
> For the network of Fig. 2.183: a. Calculate 5t. b. Compare 5t to half the period of the applied signal. c. Sketch vo.
> Sketch vo for each network of Fig. 2.182 for the input shown.
> Sketch vo for each network of Fig. 2.181 for the input shown.
> Sketch iR and vo for the network of Fig. 2.180 for the input shown.
> Determine vo for each network of Fig. 2.179 for the input shown.
> Determine vo for each network of Fig. 2.178 for the input shown.
> Determine vo for each network of Fig. 2.177 for the input shown.
> Determine vo for each network of Fig. 2.176 for the input shown.
> Sketch vo for the network of Fig. 2.175 and determine the dc voltage available.
> Describe the difference between majority and minority carriers.
> Sketch vo for the network of Fig. 2.174 and determine the dc voltage available.
> Determine vo and the required PIV rating of each diode for the configuration of Fig. 2.173. In addition, determine the maximum current through each diode.
> A full-wave bridge rectifier with a 120-V rms sinusoidal input has a load resistor of 1 kΩ. a. If silicon diodes are employed, what is the dc voltage available at the load? b. Determine the required PIV rating of each diode. c. Find the maximum current t
> a. Given Pmax = 14 mW for each diode at Fig. 2.172, determine the maximum current rating of each diode (using the approximate equivalent model). b. Determine Imax for the parallel diodes. c. Determine the current through each diode at Vimax using the res
> For the network of Fig. 2.171, sketch vo and iR.
> For the network of Fig. 2.170, sketch vo and determine Vdc.
> Repeat Problem 22 with a 10 kΩ load applied as shown in Fig. 2.169. Sketch vL and iL.
> Repeat Problem 22 with a silicon diode (VK = 0.7 V).
> Assuming an ideal diode, sketch vi, vd, and id for the half-wave rectifier of Fig. 2.168. The input is a sinusoidal waveform with a frequency of 60 Hz. Determine the profit value of vi from the given dc level.
> Determine Vo for the configuration of Fig. 2.167.
> Describe the difference between donor and acceptor impurities.
> Determine the level of Vo for the gate of Fig. 2.166.
> Determine Vo for the negative logic AND gate of Fig. 2.165.
> Determine Vo for the negative logic OR gate of Fig. 2.164.
> Determine Vo for the network of Fig. 2.42 with 10 V on both inputs.
> Determine Vo for the network of Fig. 2.42 with 0 V on both inputs.
> Determine Vo for the network of Fig. 2.39 with 10 V on both inputs.
> Determine Vo for the network of Fig. 2.39 with 0 V on both inputs.
> Determine Vo and I for the networks of Fig. 2.161.
> Determine Vo and ID for the networks of Fig. 2.160.
> Determine Vo1 and Vo2 for the networks of Fig. 2.159.
> Describe the difference between n-type and p-type semiconductor materials.
> Determine Vo and ID for the networks of Fig. 2.158.
> Determine the level of Vo for each network of Fig. 2.157.
> Determine Vo and ID for the networks of Fig. 2.156.
> Determine the current I for each of the configurations of Fig. 2.155 using the approximate equivalent model for the diode. FIG. 2.155 Problem 5.
> a. Using the approximate characteristics for the Si diode, determine VD, ID, and VR for the circuit of Fig. 2.154. b. Perform the same analysis as part (a) using the ideal model for the diode. c. Do the results obtained in parts (a) and (b) suggest that
> Sketch the current derating curve for the average forward current of the high-efficiency red LED of Fig. 1.52 as determined by temperature. (Note the absolute maximum ratings.)
> a. If the luminous intensity at 0° angular displacement is 3.0 mcd for the device of Fig. 1.52, at what angle will it be 0.75 mcd? b. At what angle does the loss of luminous intensity drop below the 50% level?
> a. What is the percentage increase in relative efficiency of the device of Fig. 1.52 if the peak current is increased from 5 mA to 10 mA? b. Repeat part (a) for 30 mA to 35 mA (the same increase in current). c. Compare the percentage increase from parts
> Using the information provided in Fig. 1.52, determine the forward voltage across the diode if the relative luminous intensity is l.5.
