Test 37 - Khosla’s Theory of Seepage

Question 1 ప్రశ్న 1

What fundamental seepage concept distinguishes Khosla's theory from Bligh's creep theory?

A Seepage water is assumed to creep only along the bottom contour of the impervious floor B Seepage water is treated as potential flow following a system of streamlines through the permeable foundation C All seepage is assumed to occur only through concrete joints D Horizontal seepage is neglected completely

Question 2 ప్రశ్న 2

For steady two-dimensional seepage through a homogeneous isotropic foundation, which equation forms the mathematical basis of Khosla's theory?

A ∂²φ/∂x² + ∂²φ/∂y² = 0 B Q = AV only C V² = 2gH D P = γH²

Question 3 ప్రశ్న 3

What did Khosla's analysis show about the loss of seepage head beneath an impervious floor?

A It always decreases linearly with horizontal floor length B It is zero until the downstream cutoff is reached C It is generally nonlinear and depends on the geometry of the floor, cutoffs and foundation D It depends only on the total weight of the floor

Question 4 ప్రశ్న 4

What is the central idea of Khosla's method of independent variables?

A Treating the entire barrage profile as one empirical creep path B Dividing a complex foundation profile into simpler standard profiles whose individual effects can be evaluated and appropriately combined C Ignoring all sheet piles except the upstream pile D Assuming that every pile produces the same pressure distribution

Question 5 ప్రశ్న 5

Which of the following is one of the standard simple profiles used in Khosla's independent-variable method?

A A horizontal floor of negligible thickness with a sheet pile at an end B A concrete gravity dam on intact rock with no seepage C A pressure tunnel surrounded by impermeable rock D An earth dam with an inclined clay core

Question 6 ప్రశ్న 6

In Khosla's method, pressure percentages are principally determined at which locations?

A Only at the centre of every concrete block B At key points such as floor-pile junctions, pile tips and relevant corners of depressed floors C Only at the upstream river bank D Only at the downstream water surface

Question 7 ప్రశ్న 7

At a particular key point, Khosla analysis gives a residual pressure of 65 percent of the total seepage head. If H = 6.0 m, what are the residual pressure head and corresponding uplift pressure intensity for γw = 9.81 kN/m³?

A 3.90 m and approximately 38.26 kPa B 2.10 m and approximately 20.60 kPa C 6.00 m and approximately 58.86 kPa D 0.65 m and approximately 6.38 kPa

Question 8 ప్రశ్న 8

For a simple horizontal impervious floor without an effective downstream cutoff, what important conclusion follows from Khosla's potential-flow solution near the downstream exit?

A The exit gradient is theoretically zero B The exit gradient is theoretically infinite, demonstrating the need for a downstream cutoff C The uplift pressure is zero throughout the floor D The floor length becomes irrelevant

Question 9 ప్రశ్న 9

Why is the downstream cutoff especially important according to Khosla's theory?

A It controls only the upstream pond level B It reduces the critical concentration of seepage gradient near the downstream exit and helps prevent piping or undermining C It eliminates all seepage beneath the structure D It is provided only to increase the crest height

Question 10 ప్రశ్న 10

For a simple profile consisting of a floor of length b and a downstream cutoff of depth d, which expression represents Khosla's exit gradient?

A GE = (H/d)[1/(π√λ)], where λ = [1 + √(1 + α²)]/2 and α = b/d B GE = L/H C GE = H/b² D GE = πHd√λ

Question 11 ప్రశ్న 11

A hydraulic structure has H = 6 m, floor length b = 40 m and downstream cutoff depth d = 5 m. Using α = b/d, λ = [1 + √(1 + α²)]/2 and GE = (H/d)/(π√λ), what is the approximate exit gradient?

A 0.179, approximately 1 in 5.57 B 0.500, approximately 1 in 2 C 0.075, approximately 1 in 13.3 D 1.20, approximately 1.2 in 1

Question 12 ప్రశ్న 12

For the structure in the previous numerical example, if the specified permissible exit gradient for the foundation soil is 0.20, what does the Khosla check indicate?

A Unsafe because 0.179 is greater than 0.20 B Safe with respect to the stated criterion because 0.179 is less than 0.20 C Unsafe because every exit gradient must be zero D The result cannot be compared with a permissible exit gradient

Question 13 ప్రశ్న 13

For fixed seepage head and floor length, what is the general effect of increasing the depth of the downstream cutoff in Khosla's formulation?

A It generally reduces the exit gradient and improves piping safety B It always increases the exit gradient C It has no effect on the seepage field D It converts the foundation into an impermeable material

Question 14 ప్రశ్న 14

For a fixed seepage head and downstream cutoff depth, what is the general effect of increasing the impervious floor length in the simple Khosla exit-gradient relation?

A It tends to reduce the exit gradient by increasing the geometric parameter λ B It makes the exit gradient theoretically infinite C It has exactly the same effect as removing the downstream cutoff D It necessarily increases the exit gradient

Question 15 ప్రశ్న 15

Which statement most appropriately compares the hydraulic roles of upstream and downstream cutoffs?

A Only the upstream cutoff has any influence on seepage B Both influence uplift and the seepage field, but the downstream cutoff is particularly important for controlling the exit gradient and piping C Only the downstream cutoff affects uplift pressure anywhere under the floor D Neither cutoff affects pressure distribution

Question 16 ప్రశ్న 16

Which three corrections are conventionally applied when Khosla's standard-profile pressure percentages are used for an actual barrage or weir profile?

A Corrections for rainfall, evaporation and reservoir sedimentation B Corrections for mutual interference of piles, floor thickness and floor slope C Corrections only for water temperature and viscosity D Corrections for canal duty, delta and base period

Question 17 ప్రశ్న 17

Why is a correction for mutual interference of piles required in Khosla's method?

A Because each sheet pile in a real profile can modify the seepage field and pressure effect associated with neighboring piles B Because sheet piles have no influence on seepage unless they touch C Because mutual interference applies only to surface-flow velocity D Because it corrects the concrete density of the floor

Question 18 ప్రశ్న 18

Why is a floor-thickness correction required in Khosla's method?

A Because standard-profile solutions normally assume negligible floor thickness, while the actual pile-floor junction may lie at a different elevation B Because concrete thickness changes the permeability of the entire alluvial deposit C Because all floors must be treated as infinitely thick D Because floor thickness affects only surface-wave height

Question 19 ప్రశ్న 19

For the conventional Khosla slope correction, what sign is applied to a floor slope when considered in the direction of seepage flow?

A Positive for a downward slope and negative for an upward slope B Negative for both upward and downward slopes C Positive for an upward slope and zero for a downward slope D The correction has no sign convention

Question 20 ప్రశ్న 20

A standard-profile calculation gives a pressure of 58 percent at a key point. If the already-evaluated corrections applicable at that point are +3 percent for pile interference, -2 percent for floor thickness and +1 percent for floor slope, what corrected pressure percentage results?

A 54 percent B 58 percent C 60 percent D 64 percent

Question 21 ప్రశ్న 21

What important foundation assumption underlies the usual Khosla standard solutions?

A The permeable foundation is idealized as extending to effectively infinite depth B The foundation must be completely impermeable C The foundation is assumed to consist only of concrete D The depth of permeable soil can never affect seepage

Question 22 ప్రశ్న 22

According to Central Water Commission guidance, the infinite-depth approximation used in Khosla theory gives practically comparable results when the depth of the pervious stratum is at least approximately which value?

A The smaller of one cutoff depth or one-half the barrage length B Five times the cutoff depth or 2.5 times the length of the barrage, whichever is larger C Exactly equal to the concrete floor thickness D One tenth of the downstream cutoff depth

Question 23 ప్రశ్న 23

How are Khosla pressure percentages used in assessing the structural requirement of an impervious floor?

A They help determine residual uplift pressures that the floor must safely resist B They determine only the colour of the concrete C They replace every structural-load calculation D They are used only to determine the river flood discharge

Question 24 ప్రశ్న 24

Which comparison between Bligh's and Khosla's approaches is most accurate?

A Bligh uses a bottom-contour creep concept and average gradient, whereas Khosla uses potential-flow solutions, pressure distribution and local exit-gradient considerations B Both theories assume exactly the same linear pressure distribution C Khosla ignores sheet piles while Bligh treats them rigorously by Laplace's equation D Bligh is based on potential flow while Khosla uses only an empirical creep coefficient

Question 25 ప్రశ్న 25

Which sequence best represents the engineering use of Khosla's method for a complex weir or barrage foundation?

A Select a creep coefficient, multiply it by head, and ignore all pile geometry B Idealize the complex profile into standard components, determine key-point pressure percentages, apply applicable corrections, check uplift and exit gradient, and revise floor or cutoff geometry if necessary C Calculate only the surface-flow velocity and adopt the same floor for every soil D Determine only the upstream cutoff depth and omit the downstream pile

Question 26 ప్రశ్న 26

Consider the following statements about Khosla's theory: I. Seepage beneath a hydraulic structure is treated as potential flow through the foundation. II. Head loss beneath the floor is generally nonlinear. III. A downstream cutoff is important for controlling the exit gradient. IV. Standard-profile pressures may require corrections for pile interference, floor thickness and floor slope. Which option is correct?

A I and II only B I, II and III only C II, III and IV only D I, II, III and IV

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