sample reviewer GEO

hydraulics and geotechnical engineering 2003-2012 zherrinore..

1) -the father of modern soil mechanics a) terzaghi b) peck c) cassagrande d) atterberg e) none of these 2) the densification of soil by removal of air which requires mechanical energy is called a) densification b) compaction c) consolidation d) liquefaction e) none of these 3) deep groundwater deposits where underground water are available for water supply and irrigation is known as a) water table b) water wells c) aquifers d) saturated zone e) none of these 4) in fluid flow, if the fluids travels parallel to the adjacent layers and the paths of individual particles do not cross the flow is said to be a) laminar b) turbulent c) critical d) dynamic e) none of these 1) A soil sample has a natural water content of 22.5% and it is known to have a sp. gr. of 2.6. in order to determine the moist density of the soil, a portion of soil weighing 3 224 g is put in a 500 cm container. It is filled with 382 3 cm of water to fill the container. A. Determine the moist unit of the soil. B. Determine the dry unit of soil. C. Determine the void ratio. 2) The total weight of soil when saturated 1526 g and weight of the soil after drying is 1053 g. If the sp. gr. of soil is 2.84 A. Compute the moisture content B. Compute the void ratio C. Compute the porosity 3 3) The field unit wt of the soil sample is 1960 kg/m and the 3 unit wt of the soil particle is 2700 kg/m . If the emax = 0.69 and emin=.44 3 A. Compute the dry unit wt in KN/M if the water content is 11%. B. Compute the void ratio of the solid sample C. Compute the relative density of the soil sample. 3 4) The field wt of soil sample is 1900 kg/m and the unit wt 3 of the soil particle is 2660 kg/m . A. Compute the dry unit weight if the moisture content is 11.5%. B. Compute the void ratio. C. Compute the degree of saturation.

5)

A soil sample has a mass of 1830 g taken from the field -3 3 having a volume of 1. x 10 M g taken from the field 3 3 having a volume of 1.x10 M . it has specific gravity of max 2.60 and water content of 10%. Values of e = .63 and min e = .44 A. Compute the dry unit weight. B. Compute the void ratio. C. Compute the relative density.

6) A soil sample has a natural water content of 22.5% and it is known to have a specific gravity of 2.6. in order to determine the moist density of the soil, a portion of soil 3 weighing 224 g is put in a 500 cm . It is filled with 382 3 cm of water to fill the container. A. Compute the porosity of the soil. B. Compute the degree of saturation. C. Compute the bulk of sp. gravity. 7) A dry soil mixed with 17% by mass with water and 3 compacted. Volume of wet soil is 0.001 m and has a ass of 1.6 kg. If the specific gravity of soil is 2.70. A. Compute the dry unit weight of soil. B. Compute the void ratio. C. Compute the degree of saturation. 8) A dry soil is mixed with 13.5% by mass with water and -3 3 compacted . volume of wet soil is 1x10 m and has a mass of 1.6kg. if the specific gravity of soil is 2.61 a) compute the dry density b) compute the void ratio c) compute the degree of saturation 3 9) the field unit wt of soil sample is 1900kg/m and the unit 3 wt of the soil particle is 2600 kg/m a) compute the dry unit wt if the water content is 12% b) compute the void ratio c) compute the degree of saturation 10) you are an earthwork construction control inspector and you are checking the field compaction of a layer of soil. the laboratory compaction curve gives a maximum dry density of 1.482g/cc and optimum water content of 16.9%. specifications call for the compacted density to be at least 95% of the max laboratory value and within +-2% of the optimum water content. when you did the sand cone test, the following data are as follows. 3 volume of soil excavated from the hole=.001337m weight of soil from the hole when wet=2200 g wt of dry soil=1890g a) determine the field unit wt of soil b) what is the insitu water content of soil c) determine the relative compaction of the soil 11) given the different layer of soil with their respective coefficient of permeability:

hydraulics and geotechnical engineering 2003-2012 zherrinore.. a)

what is the equation in determining the equivalent horizontal coefficient of permeability b) what is the equivalent horizontal coefficient of permeability if each soil layer is 3mm thick c) what is the total flow if i=.70? d) 12) a confined aquifer underlies an unconfined aquifer as shown in the figure

a) determine the total flow of water b) fins the equivalent value of K for both annular and inner ring c) determine the volume of water which percolate 3 after 30 mins in cm 16) the laboratory apparatus shown in the figure maintains a constant head in both the upper and lower reservoirs. the soil sample is a silty sand wih a hydraulic conductivity -3 k=5x10 cm/sec and a moisture content of 18.5%. sp. gr=2.70

a)

compute the equivalent horizontal coefficient of permeability b) compute the hydraulic gradient c) compute the flow rate from one stream to another per meter width 2 13) a reservoir with a 3400m area is underlain by layers of stratified soils as depicted in the figure

a)

compute the average coefficient of permeability in m/hr b) compute the interstitial velocity of water moving through the soil if it has a void ratio of .60 express in cm/.sec c) compute the water loss from the reservoir in one yr in cu.m assuming that pore water pressure is zero 14) the soil under a dam has four layers of soil with different coefficients of permeability Layer Depth Coefficient of permeability 1 4 5 cm/hr 2 8 3 3 12 2 4 3 1 a)

compute the average vertical coefficient of permeability in meters/day b) compute the transmissibility of the soil when the 2 water table is at the ground surface in m /day c) compute the interstitial velocity of water moving through the soil if it has e=.6 and i=.0018cm/hr 15) a test is set up as shown in the figure below.

a) compute the seepage velocity in cm/sec b) determine the time required for the plug of colored water to pass through the soil. c) compute the discharge of water 17) a confined aquifer has a source of recharge as shown in the figure. the hydraulic conductivity of the aquifer is 40m/day and its porosity is .25. the piezometric head in the two well 1325m apart is 65m and 60m from a common data. the average thickness of the aquifer is 25m. and the average width is 4km

a)

compute the rate of flow through the aquifer in 3 m /day b) compute the seepage velocity c) compute the time of travel from the head of the aquifer to a point 4km downstream in days 18) a dense silt layer has the following properties: voidratio=.30 effective diametr D10=10μm 2 capillary constant=.20cm a) find the height of the capillary rise in the silt b) find the vertical effective stress in kPa at 5m depth. 3 assume γs=26.5kN/m and that the soil above the capillary action rise and ground surface is partially saturated at 50% c) find the vertical effective stress in kPa at 10m depth. assume γs=26.5kN/m3 and that the soil above the capillary action rise and ground surface is partially saturated at 50% 19) a saturated clay having a thickness of 20m has a void ratio of .68 and sg of 2.7 a) compute the density of clay

hydraulics and geotechnical engineering 2003-2012 zherrinore..

20)

21)

22)

23)

24)

b) compute the total vertical stress at the bottom c) compute the effective stress at the bottom a thick layer of clay underlies a sand formation having a thickness of 4.5 m. the groundwater is located 2n below the ground surface. sp.gr. of sand and clay is 2.65 with sand having an average void ratio of .52. the clay has water content of 42% degree of saturation above the water table is .37 a) compute the unit wt of sand above the water table b) compute the total stress at a depth of 10m below the ground surface c) compute the effective stress at a depth 10m below the ground surface a saturated clay layer has a thickness of 10m with water content of 51% and sg=2.72 a) compute the unit wt of the clay b) compute the ottal stress at the bottom c) compute the effective stress at the bottom a given soil layer has a dry unit wt of 14.72 kn/m3 and a saturated unit wt of 20.12 kn/m3 . the ground water table is located 2m below the ground surface a) what is the total stress at point A 4.5 m below the ground surface b) what is the pore pressure at point A 4.5 m below the ground surface c) what is the effective stress at point A 4.5 m below the ground surface a uniform soil deposit has a dry unit wt of 15.6 Kn/m3 and a saturated unit wt of 17.2 Kn/m3. the ground water table is at a distance of 4m below the the ground surface. point A is at a depth 6 m below the ground surface a) compute the effective stress at A b) if the water table goes up by 3.5 m, compute the effective stress at A c) in comparison to question 1 and 2, what will happen to the effective stress at A if the ground water level will rise up to the ground surface from the given soil profile shown, the ground surface is subjected to a uniform increase in vertical pressure of 2 12n/cm

a) determine the depth of the footing b) determine the increase in pressure in the soil when the tank is filled with oil c) determine the settlement of the clay layer. assume that the swell index is equal to 1/5 of the comp. index 26) two footings rest in a layer of sand 2.7m thick. thr bottom of the footings are .90m below the ground surface. beneath the sand layer is a 1.8 m clay layer. beneath the clay layer is hard pan. the water table is at a depth of 1.8m below the ground surface. void ratio of clay is 1.03

a)

compute the stress increase in the center of the clay layer,assume that the pressure beneath the footing is spread at an angle of 2 vertical 1 horizontal b) determine the size of footing B so that the settlement in the clay layer is the same beneath footings A and B. footing a is 1.5m c) determine the settlement beneath footing A 27) a square footing 3mx3m carries a column load of 3500 kn resting on a sand layer as shown on the figure. unit wt of 3 sand above the water table is 17.31 kN/m and has a 3 saturated unit wt of 18.10 kn/m below the water table. the sand overlies a clay layer 1.2m thick having a 3 saturated unit wt of 16.50 kn/m and a void ration of 1.7 compression index:Cs=.07, Cc=.35 assume a vertical stress distribution of 2v:1h

a)

a) compute the buoyant unit wt of clay b) compute the overburden pressure at the mid-height of the clay c) compute the total settlement due to primary consolidation 25) a tank shown in the figure has an inside diameter of 8m and a height of 6m. it is used as a storage of oil with sg=.80. the combined wt of the empty tank and the footing is 2800 KN

compute the preconsolidation pressure Pc if OCR=2.0 b) compute the total effective stress at the center of the clay layer c) calculate the settlement due to the consolidation of the clay layer when it is overconsolidated 28) a retaining wall 8m high is supporting a horizontal backfill 3 having a dry unit wt of 1600 kg/m . the cohesionless soil has an angle of friction of 33° a) compute the rankine active force on the wall

hydraulics and geotechnical engineering 2003-2012 zherrinore..

29)

30)

31)

32)

33)

34)

b) compute the rankine active force on the wall if the water table is located at a depth of 3.5m below the 3 ground surface. the sat unit wt is 18.7 kn/m c) compute the location of the resultant active force from the bottom for the second condition a vertical retaining wall 6m high retains a horizontal backfill having the following properties: void ratio=.60 sG=2.6 water content=24% Angle of internal friction=25° a) compute the magnitude of the active force acting on the wall if the water table is on the ground surface which is on level with the top of the wall b) compute the magnitude of the active force acting on the wall if the water table is located at a depth of 3m from the ground surface c) compute the magnitude of the active force if the water table is at the bottom of the wall. a consolidated drained triaxial test was conducted on a normally consolidated clay. the results were as follows chamber confining pressure=138kpa deviator stress=258kpa a) compute the friction angle of the soil b) compute the normal stress at failure c) compute the shear stress at failure a cohesionless soil has a friction angle of 30° and a deviator stress of failure of 400kpa a) find the angle that the failure plane makes with the major principal plane b) find the confining pressure c) finds the shear stress at the point on the failure plane a cohesive soil specimen has a shearing resistance equal to 28° and a cohesion of 30kpa. if the max shearing stress of the soil is equal to 70kpa a) compute the lateral pressure in the cell for a failure to occur b) compute the maximum principal stress to cause failure c) compute the normal stress at the point of max. shear in a triaxial test fpr normally consolidated soil, the normal stress at failure is equal to 465kpa and the shear stress at failure is equal to 350kpa a) compute the angle of friction b) compute the angle of the failure plane with the major principal axis c) compute the max principal stress at failure in the triaxial test for normally consolidated soil, the deviator stress is equal to 340 kpa and the angle of the failure plane makes with the major principal plane is equal to 60° a) compute the shearing stress at the plane of failure b) compute the normal stress c) compute teh value of teh confining pressure

35) a soil specimen is subjected to a triaxial test. the soil specimen is cohesionless. if the shear stress that causes failure is 300kpa and the normal stress at failure is only 375 kpa a) determine the angle of shearing resistance b) determine the angle that the failure plane measured from the major principal plane c) determine the total axial stress at which failure is expected to occur 36) the max stress that causes failure of a cohesive soil specimen in a triaxial test is equal to 220 kpa. the angle of friction is equal to 25°. if the deviator stress at failure is equal to 140kpa a) compute the confining chamber pressure b) compute the cohesion of soil c) compute the shearing stress at the point of the failure plane 37) the following data were obtained from a triaxial test of a normally consolidated soil, deviator stress at failure=800kpa, angle to failure plane from the major principal plane=63° a) compute the shearing stress at the plane of failure b) compute the normal stress at the plane of failure c) compute the value of the confining pressure 38) a .36 m square prestressed concrete pile is to be driven in a clayey soil as shown in the figure. the design capacity of the pile is 360KN, with FS=2

a) compute the end bearing capacity of pile b) compute the skin friction expected to develop along the shaft of the pile c) compute the length of pile if α=.76 39) a .30mx.30m concrete pile 22m long is driven in a clayey soil having an unconfined compressive strength of 110 2 3 kn/m . the unit wt of the clayey soil is 18kn/m . frictional constant is .76 due to skin friction. assume FS=2 and Nc=9 a) compute the capacity of the pile due to skin friction only b) compute the end bearing capacity c) compute the design capacity of the pile 40) a .3m square concrete pile is to be driven at a site where soil conditions are as indicated in the figure. if a penetration of 14m is assumed

hydraulics and geotechnical engineering 2003-2012 zherrinore..

a)

what total skin friction is expected to develop along the embedded length of the pile b) compute the total end bearing capacity of the pile if Nc=9 c) what is the design capacity of the pile if it has a factor of safety of 2 41) a pile group consists of 12 piles with a diameter f .3 m and a pile length of 12 m is shown in the figure. the piles are spaced in a 3pile by 4 pile rectangular configuration with a pile spacing of .6m center to center of piles. the piles are driven into the clay that has the given characteristics. the piles penetrate a soft clay(c=20kpa) medium dense clay(c=56kpa) and stiff clay(c=95 kpa), use α=1 for soft and medium dense clay and .5 for stiff clay.

a)

42)

43)

44)

45)

determine the capacity of the pile group based on the single pile failure mode b) determine the capacity of the pile group based on block failure mode c) determine the minimum center to center spacing of piles to achieve 100% efficiency a nine pile group consists of .30 m diameter friction concrete piles 12m long. the piles are driven into clay 2 having a cohesion of 50 kn/m and the unit wt of clay is 19.2. the spacing of piles is .75m center to center. assuming Nc=9 and α=1 a) find the allowable group pile capacity based on individual pile failure using FS=3 b) find the block capacity of pile group using FS=3 c) find the minimum spacing in order to achive 100% efficiency a group of friction piles is shown in the figure. the total load on the pile less the weight of the soil displayed by the foundation is 1800kn. thickness of silt is 2m and that of clay is 16m a) determine the effective overburden pressure at midheight of the consolidating clay b) determine the compression index of the clay layer c) determine the settlement of the pile foundation a soil sample was determined in the laboratory to have a liquid limit of 41% and a plastic limit of 21.1%. if the water content is 30%, determine the following a) plasticity index b) liquidity indez c) characteristic of the soil given the LL of soil=58% and its PL=8%

a) what are these properties of soil b) determine the plasticity index c) what is the liquidity index if w=30% 46) From the given table shows the LL and PL of soil x and y Soil Liquid limit Plastic limt X 47 22 Y 70 38 a) find the PI of soil x b) find the PI of soil y c) what is the purpose of the test 47) a 300 mm diameter test well penetrates 27m below the static water table. after 24 hours of pumping at 69l/sec the water level in the observation well at a distance of 95 m from the test well is lowered .5m and the other observation well at a distance of 35m from the testwell, the drawdown is 1.1m 3 a) what is the rate of flow in m /day b) compute the coefficient of permeability of the aquifer in m/day 2 c) compute the transmissibility of the aquifer in m /day 48) a 7m deep braced cut in sand is shown. in the plan, the struts are placed at a spacing of 2m center to center. using pecks empirical pressure diagram, compute the following

a) strut load at level A b) strut load at level C c) strut load at level B 49) the hydraulic gradient for quicksand condition is equal to 1.13 with a void ratio of .50. the moist unit wt of soil is 3 19.04kn/m a) compute the SG of the soil b) compute the dry unit wt of the soil c) compute the water content of the soil 50) the results of a constant head permeability test for a fine sand and sample having a diameter of 150mm and a length of 150mm are as follows constant head difference=40cm time of collection of water=83sec weight of water collected=39 g a) find the hydraulic conductivity 51) from a constant laboratory permeability test on a fine sand the following are given length of specimen=17cm diameter of specimen=5.5cm constant head difference=40cm weight of water collected=50g duration=12sec a) find the hydraulic conductivity

hydraulics and geotechnical engineering 2003-2012 zherrinore.. 52) an anchored sheet pile supports a mass of soil 7.3m high with a horizontal surface. the angle of friction of the soil 3 is 31° with a unit wt of 1.96g/cm . the total height of the sheet pile is 10.5 m which is supported by an anchor bolt placed 1.2 m below the ground surface which has a spacing of 3m center to center a) compute the active force b) compute the fraction of the theoretical-maximum passive resistance of the total embedded length which must be mobilized for equilibrium c) compute the tension in the anchor bolt 53) a cantilever sheet pile is 8,2 m long with a depth of embedment of 3.2m. angle of friction of the soil supported by the sheet pile is 34° and has a unit weight of 1.91g/cc. there is water table below the base of the sheet pile a) compute the active force acting on the sheet pile b) compute the max passive force acting on the sheet pile c) compute the theoretical passive force that must be mobilized to ensure stability 3 54) from the figure sown, the soil has a unt wt of 18kn/m 2 and undrained shear strength cu=20kN/m . the slopes makes an angle of 60° with the horizontal, assume a stability number m=.185

a) compute the stability factor b) compute the maximum depth up to which the cut could be made c) compute the angle that the failure plane makes with the horizontal if BC=8m 55) a piece of metal weighs 350N in air and when it is submerged completely in water, it weighs 240N a) find the volume of the metal b) find the specific wt of the metal c) find the specific gravity of the metal 56) a wooden storage vat full of oil sp. gr=.80 is in the form of frustum of a cone 2m diameter at the top and 4m diameter at the bottom and 3 m high. it is provided with 2 steel hoops one at the top and one at the bottom a) compute the hydrostatic force on the side op the container b) how high is the said force above the bottom c) compute the force on the bottom hoop 57) a vat holding paint(SG+.8) is 8m long and 4 m deep and has a trapezoidal cross section 3m wide at the bottom and 5m wide at the top a) compute the weight of the paint b) compute the force on the bottom of the vat c) compute the force on the trapezoidal end panel 58) from the figure shown, the clay is normally consolidated. a laboratory consolidation test on the clay gave the following results Pressure(kPa) Void ratio, e

100 200

.905 .815

a)

calculate the average effective stress on the midheight of clay layer i) 60.74kPa ii) 42.24 iii) 36.36 iv) 69.23 v) 78.95 b) determine the compression index cc i) .213 ii) .452 iii) .374 iv) .465 v) .299 c) if the average effective stress on the clay layer is increased(Po+∆P) to 115kPa, what would be the total consolidation settlement? i) 123.65mm ii) 104.6 iii) 158.74 iv) 116.35 v) 92.56 59) a tube having a cross sectional area of 100 sq.cm contains three layers of soil having given hydraulic conductivities as shown in the tabulation. the rate of water supplied to maintain a constant head of 400mm is 3 291.21cm /hr. if the value of Ha=300mm and Kb=4x10 3 cm.sec a) compute the value of Ka b) compute the value of Hb c) compute the value of Kc 60) a wooden buoy of sg=.75 floats in a liquid with sg=85 a) what is the percentage of the volume above the liquid surface to the total volume of the buoy i) 13.6 ii) 14.1 iii) 15.6 iv) 12.3 v) 11.8 3 b) if the volume above the liquid surface is .0145m what is the weight of the wooden buoy? i) .698kN ii) 957 iii) .905 iv) .789 v) .821 c) what load that will cause the buoy to be fully submerged? i) .121kN

hydraulics and geotechnical engineering 2003-2012 zherrinore.. ii) .151 iii) .216 iv) .178 v) .236 61) the reading of a Toyota 6x-2003 fuel gage is proportional to the gage pressure at the bottom of the tank as shown on the figure. the tank is 32m deep. unit wt of gasoline is 3 3 6670N/m and that of air is 11.8N/m . unit weight of 3 water is 9790 N/m a) determine the gage reading when the tank is full of gasoline i) 2231.2kPa ii) 2056.7 iii) 2365.8 iv) 2134.4 v) 2518.6 b) how many cm of air remains at the top when the gage indicates full if the tank is 32 m deep and is contaminated with 3cm of water i) 2.15cm ii) 1.87 iii) 1.41 iv) .26 v) 1.12 2 c) if the tank is .5m , find the volume of the gasoline to fill up the tank i) 60liters ii) 70 iii) 90 iv) 80 v) 50 62) a tank with vertical sides is 1.2 m square, 3.0 m deep and is filled to a depth of 2.7m with water. a cube of wood having a specific gravity of .5 measuring 60 cm on the edge is placed in the water so that it will float a) find the weight of volume of water displaced i) 2.36 ii) 1.75 iii) .26 iv) 3.85 v) 1.0 b) determine the depth that the water will rise inside the tank from its original water level i) .025m ii) .015 iii) .075 iv) .123 v) .042 c) what will be the change in pressure on one side of the tank? i) 1.451 ii) 2.875kN iii) 2.417 iv) 3.052 v) .051 63) a square plate having one of its side equal to 3m is immersed in a water surface in a vertical position such

that the two edges of the square would be horizontal in order that the center of pressure shall be 8cm from the center of gravity. a) how far below the water surface should the upper plate be submerged? i) 5.258 ii) 7.875 iii) 6.154m iv) 8.715 v) 9.875 b) what is the distance of the center of pressure from the water surface i) 10.365 ii) 6.271 iii) 8.784 iv) 7.265 v) 9.455 c) determine the hydrostatic force acting on the plate at this position i) 748.59 ii) 827.27kN iii) 936.65 iv) 615.48 v) 889.99 64) an open cylindrical vessel 1 m in diameter contains water at a depth of 3.56m. a) if it is rotated at a speed of 80rpm about its vertical axis determine the least depth of the vessel so that no water will be spilled out i) 4 ii) 3 iii) 5 iv) 6 v) 2 b) if the vessel is rotated at 120rpm, how much water will be spilled out? i) 425 ii) 486 iii) 465 iv) 405 v) 444 c) if the vessel is rotated at 140 rpm, what would be the pressure at the center bottom of the tank? i) 12.36kPa ii) 10.35 iii) 15.72 iv) 18.18 v) 22.36 65) from the figure shown, the gate is 1m wide and is hinged at the bottom of the gate

a)

compute the hydrostatic force acting on the gate

hydraulics and geotechnical engineering 2003-2012 zherrinore.. b) compute the location of the center of the pressure of the gate to the hinged c) Determine the minimum volume of concrete 3 (γ=23.6kN/m ) needed to keep the gate in a closed position. 66) a vertical plate shown is submerged in vinegar having a 3 sg=.80. assume γw=9.79kN/m

a)

find the depth of the center of pressure of section A from the liquid surface b) find the magnitude of the hydrostatic force on one side of the plate c) find the depth of the center of pressure of the whole section from LS 67) a vertical rectangular gate as shown is 2m wide, 6 m high is hinged at the top has oil sg=.84 standing 7m deep on one side, the LS being under pressure of -18.46kPa

c) how soon after will the water surface be 4m apart? 2 71) an orifice having an area of .00785m is attached to a vertical side of a cylindrical tank having a diameter of 4m. the weight of the water discharged in 1 min and 40 sec is 22563N under a constant head of 1.2m. the jet strikes a point 1.92m horizontally from the vena contracta and .80m vertically below the orifice a) find the coefficient of velocity b) find the coefficient of discharge c) compute the coefficient of contraction 72) two closed compartments A and B are connected by an orifice having a diameter of 140mm diameter at its sides. at compartment A, it contains water at a depth of 3m above the orifice and a pressure on top of it equal to 50kPa. on the other compartment, it contains water at a depth of 2m above the orifice and a pressure of 15kPa on top of the water surface. c=.86 Cv=.92

73) a) compute the hydrostatic force acting on the gate b) how far is the force acting below the hinge c) how much horizontal force applied at the bottom is needed to open the gate 68) the tank in the figure is 3m wide into the paper. neglecting atmospheric pressure. compute the following. 3 use γw=9.79kN/m a) vertical force on the quarter circle panel BC b) horizontal force on the quarter circle c) resultant force on the quarter circle panel BC d) angle that the resultant makes with the horizontal 69) a square plate having one of its side equal to 3m is immersed in a water surface in a vertical position such that the two edges of the square would be horizontal in order that the center of pressusre shall be 10 cm from the center of gravity a) how far below the water surface should the upper plate be submerged b) what is the distance of the center of the pressure from the water surface c) determine the hydrostatic force acting on the plate 70) two open cylindrical tanks are connected by an orifice 2 having a cross sectional area of .004m . tank A is 8m in diameter and its water level is 10 m above that of B whose diameter is 5m. if the coefficient of discharge is .60 a) find the discharge flowing in the orifice b) how long will it be before the water surface are at the same level

74)

75)

76)

77)

a) compute the discharge thru the orifice b) compute the headloss c) compute the power loss in watts a trapezoidal channel has a bottom width of 6m and side slopes of 2 horizontal and 1 vertical. when the depth of 3 flow is 1.2m, the flow is 30.40 m /s a) compute the specific energy b) compute the slope of the channel if n=.014 c) compute the average shearing stress at the boundary the cross section of a right triangular channel is shown with a coefficient of roughness n=.012. if the rate of flow 3 is 4m /s a) det. the critical depth b) det. the critical velocity c) determine the critical slope a rectangular channel 6m wide has a constant specific energy of 2.2 a) calc the critical depth b) cal the critical velocity c) cal the critical slope if n=.012 3 a rectangular channel carries a discharge of 17.6m /s when flowing 1.2 m depth. if the width of the canal is 10m a) compute the min specific energy b) compute the normal slope if n=.014 c) compute the average shearing stress of the boundary water flows through an almost level channel 3.0 m wide 3 at 12m /s. the depth gradually increase from 1.0m to 1.1m for a length of flow of 5m a) what is the HL b) what is the slope c) compute for n

hydraulics and geotechnical engineering 2003-2012 zherrinore.. 78) a pump draws water from reservoir A and lifts it to a reservoir B as shown. the loss of head from A to 1 is 3 times the velocity head in the 150mm pipe and the loss of head from 2 to B is 20 times the velocity head in the 100mm pipe. when the discharge is 20L/sec

a) compute the horse power output of the pump b) compute the pressure head at 1 compute the pressure head at 2 79) two reservoirs A and B have elevatons of 250m and 100m respectively. it is connected by a pipe having a diameter of 250mm and a length of 100m. a turbine is installed at a point in between the reservoirs A and B. if c=120, compute the ff if the discharge flowing in the pipe is 150liters/sec

a) headloss of pipe due to friction b) head extracted by the turbine c) power generated by turbine 80) a rectangular channel 5.4m wide by 1.2 m deep is lined with a smooth stone well and has a hydraulic slope of .001. using n=.012 3 a) what is the capacity of the channel in m /s b) what savings in earth excavation could have been offered by using more favourable proportional but adhering to the same delivery and slope c) what savings in lining per meter length could have been offered by using more favourable proportional but adhering to the same delivery and slope 81) a trapezoidal canal has a base width equal to 6m which carries water flowing at velocity of .8m/s a) compute the discharge in the canal if the side are sloping at an angle of 45° such that it will have a minimum seepage b) compute the discharge in the canal for MES c) compute the discharge if the depth of the canal is only 2/3 of the base width and has side slopes of 1:1 82) water from a reservoir flowing througha non rigid 600mm pipe with a velocity of 2m/s is completely stopped by a closure of a valve situated 150 m from the reservoir. assume that the pressure increases at a uniform rate and that there is no damping of the pressure wave. the pipe has a thickness of 20mm. bulk 9 modulus of water is 2.2x10 mPa and modulus of 11 elasticity of steel is 1.4x10 mPa a) compte the velocity of sound of water

b) find the water hammer pressure for instant closure c) how much time should be allowed for closing the valve to avoid water hamer? 83) the error in the measured head in a channel is equal to 3 0.018m. if the discharge flowing the channel is .6m /s. compute the following a) %error if a suppressed rectangular weir is used with length of weir is equal to 4.2m b) % of error if a cipolletti weir having a length of weir of 4.6m c) % of error if a right triangular weir is used# 84) a 600mm diameter steel pipe, 10mm thick carries water under a head of 325m a) determine the actual stress in kN per meter length of pipe b) if the head is increased to 500m, what is the actual stress on the wall in Mpa c) if the head is increased to 500m, what thickness is required assuming an allowable tensile stress of 113mPa and efficiency of the connection is 80% 85) the velocity of oil flowing thru a 30mm diameter pipe is -5 2 equal to 2m/s. oil has kinetic viscosity of 5x10 m /s. if the pipe has a length of 120m a) compute the Reynolds number b) compute the friction factor c) compute the headloss of the pipe 86) a liquid having a Reynolds number of 1900 flow thru a 200 mm diameter pipe 150m long. the headloss of the pipe due to friction is 22m a) compute the friction factor b) compute the kinematic viscosity c) compute the rate of flow in l/sec 87) a closed cylindrical tank having a radius of .6m and a height of 4m is full of water under a pressure of 196.2 kPa. the metal side is 3mm thick. if the vessel is rotated at 200rpm a) compute the total pressure on the side of the wall b) compute the total pressure against the top c) compute the maximum intensity of the hoop on tensile side 88) a footing 6m square carries a total load, including its own weight of 10000 KN. the base of the footing is at a depth of 3m below the ground surface. the soil strata at the site consists of a layer of stiff fully saturated clay 27.5m thick overlying dense sand. the average bulk density of the clay 3 is 1920kg/m and its average shear strength determined 2 from undrained triaxial test is 130kN/m . from the table, a) determine the gross foundation pressure b) determine the net foundation pressure c) calculate the factor of safety of the foundation against the complete shear failure under the undrained condition. side cohesion on the foundation may be neglected 89) a square footing has a dimension of 1.2m by 1.2m and has its bottom 1m below the ground surface

hydraulics and geotechnical engineering 2003-2012 zherrinore..

a)

if the ground water table is located at a depth of 1.2m below the ground surface. compute the allowable load that the footing could carry if it has a factor of safety of 3 b) find the ultimate bearing capacity of the soil if the ground water table is at the bottom of the footing c) find the ultimate bearing capacity of the soil if the ground water table is .5m above the bottom of the footing 90)