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Question 1
ప్రశ్న 1
What is the principal hydraulic purpose of a diversion weir constructed across a river?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A diversion weir creates the head needed to divert river water into a canal or other intake system. Its primary function is therefore different from that of a high storage dam. Some pondage may occur upstream, but large seasonal storage is not normally its defining purpose. The structure must also pass river floods safely and operate without unacceptable afflux, scour or foundation distress. The crest level, waterway and associated headworks are selected to satisfy these combined functions. Therefore Option A is correct.
వివరణ:
Question 2
ప్రశ్న 2
Which description best characterizes a conventional masonry or concrete vertical-drop weir?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A traditional vertical-drop weir has a masonry or concrete body wall forming the raised crest. Its downstream face is vertical or nearly vertical rather than a long sloping glacis. Water passing over the crest drops onto a downstream floor or cistern where the excess energy must be controlled. The impervious floor also forms part of the seepage-control system when the foundation is permeable. This configuration is distinct from the modern sloping-glacis arrangement. Therefore Option C is correct.
వివరణ:
Question 3
ప్రశ్న 3
What is the defining downstream feature of a sloping-glacis weir?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A sloping-glacis weir provides a sloping downstream surface after the crest. The overflowing water accelerates along this glacis toward the downstream energy-dissipation zone. The profile is coordinated with the downstream floor and tail-water so that the hydraulic jump can occur in a controlled location. This layout differs fundamentally from the abrupt vertical fall of a vertical-drop weir. Modern seepage-control measures such as cutoffs and an impervious floor are incorporated as part of the complete structure. Therefore Option A is correct.
వివరణ:
Question 4
ప్రశ్న 4
Which statement most accurately compares the hydraulic energy-dissipation concepts of vertical-drop and sloping-glacis weirs?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The vertical-drop type allows the overflow to fall abruptly from the crest toward the downstream floor or cistern. The resulting jet and turbulence must be accommodated by appropriate downstream protection. In a sloping-glacis design, the high-velocity sheet is guided along the glacis into an energy-dissipation arrangement. The glacis and downstream floor can be proportioned so that a hydraulic jump forms in the protected region. Thus both require energy control, but their hydraulic layouts differ substantially. Therefore Option B is correct.
వివరణ:
Question 5
ప్రశ్న 5
Why is the crest level of a diversion weir an important design parameter?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The crest level directly affects the relationship between river level and the head available over the weir. It must be compatible with the pond level required to feed the canal head regulator or other intake. An unnecessarily high crest can increase upstream water levels and afflux during flood conditions. A crest set too low may not provide adequate diversion head under lean-flow conditions unless gates or shutters provide additional control. Crest selection must therefore be coordinated with waterway, flood discharge, intake level and operating requirements. Therefore Option B is correct.
వివరణ:
Question 6
ప్రశ్న 6
A design flood of 1800 m³/s is to pass through a weir section at an adopted discharge intensity of 12 m³/s per metre of effective waterway. What effective waterway is required?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Discharge intensity is the total discharge divided by effective waterway. Therefore the required waterway is L = Q/q. Substituting Q = 1800 m³/s and q = 12 m³/s per metre gives L = 1800/12. The resulting effective waterway is 150 m. This simple calculation is an initial hydraulic sizing step and does not replace checks for afflux, scour, contractions and river-training requirements. Therefore Option B is correct.
వివరణ:
Question 7
ప్రశ్న 7
For an idealized free-overflow calculation, use Q = C L H^(3/2). If C = 1.70, effective crest length L = 80 m and head H = 2.0 m, what discharge is obtained?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The supplied relation is Q = C L H^(3/2). For H = 2.0 m, H^(3/2) equals approximately 2.828. Hence Q = 1.70 × 80 × 2.828. This gives approximately 384.7 m³/s. In an actual weir design, the appropriate discharge coefficient, approach conditions, submergence and effective waterway would also have to be established. Therefore Option C is correct.
వివరణ:
Question 8
ప్రశ్న 8
A weir must pass 600 m³/s under an effective head of 2.5 m. Using Q = C L H^(3/2) with C = 1.75, what effective crest length is required?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The required length is obtained from L = Q/[C H^(3/2)]. For H = 2.5 m, H^(3/2) is approximately 3.953. The denominator is therefore 1.75 × 3.953, or approximately 6.917. Dividing 600 by this value gives L ≈ 86.74 m. The result represents the effective hydraulic length under the assumptions explicitly stated in the question. Therefore Option C is correct.
వివరణ:
Question 9
ప్రశ్న 9
The required normal upstream pond-water level is RL 104.50 m. If an idealized free-overflow design requires a static head of 2.00 m above the crest and approach-velocity and submergence effects are neglected, what crest level follows?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Under the stated simplified condition, water-surface elevation equals crest elevation plus the specified head. The crest elevation is therefore 104.50 - 2.00. This gives RL 102.50 m. The calculation is intentionally simplified so that approach-velocity head, gate effects and submergence do not enter. Actual crest fixing would be coordinated with the canal requirement, flood levels, afflux and operating arrangement. Therefore Option B is correct.
వివరణ:
Question 10
ప్రశ్న 10
What is the principal foundation-related purpose of the impervious floor provided beneath and adjacent to a weir on a permeable alluvial foundation?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A hydraulic head difference exists between the upstream and downstream sides of a diversion weir. On a permeable foundation, water therefore tends to seep beneath the structure. The impervious floor forms part of the seepage-control system and helps prevent direct erosion of the foundation. It must also possess adequate thickness or structural strength to resist uplift pressures acting beneath it. Its length and relationship with cutoffs are determined by a proper subsurface-flow analysis rather than by surface hydraulics alone. Therefore Option B is correct.
వివరణ:
Question 11
ప్రశ్న 11
Which statement correctly distinguishes the general hydraulic roles of the upstream and downstream portions of a weir floor?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Both upstream and downstream floor portions participate in the subsurface seepage system. The upstream floor also protects the approach bed adjacent to the structure. The downstream floor is particularly important because high-velocity overflow and energy dissipation occur on or above it. It is also exposed to uplift pressures and must safely transfer hydraulic and structural forces to the foundation. Consequently upstream and downstream floor dimensions cannot be selected solely from the same surface-flow consideration. Therefore Option B is correct.
వివరణ:
Question 12
ప్రశ్న 12
What is the principal purpose of cutoff walls or sheet-pile lines beneath a weir on a permeable foundation?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Cutoffs extend downward below the impervious floor into the permeable foundation. They force seepage to follow a deeper and more tortuous route instead of travelling directly beneath the structure. This changes the subsurface pressure distribution and improves safety against foundation erosion and piping. The downstream cutoff is especially influential in controlling the gradient where seepage finally emerges. Exact cutoff depth and pressure effects require the seepage-analysis methods addressed separately in Bligh and Khosla theory. Therefore Option B is correct.
వివరణ:
Question 13
ప్రశ్న 13
Why is the downstream cutoff particularly important in the design of a weir on pervious soil?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Seepage water eventually emerges near the downstream end of the impervious floor. A high exit gradient there can remove foundation particles and initiate piping. A downstream cutoff forces the seepage flow deeper before it reaches the exit region and thereby helps reduce this danger. Its depth must also be sufficient in relation to expected downstream scour so that the floor is not undermined. The precise gradient and pressure distribution are obtained from a suitable seepage theory rather than from this qualitative principle alone. Therefore Option B is correct.
వివరణ:
Question 14
ప్రశ్న 14
At a point beneath a weir floor, the residual piezometric head causing upward pressure is 3.2 m of water. Taking the unit weight of water as 9.81 kN/m³, what uplift pressure corresponds to this head?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Hydrostatic pressure corresponding to a water head h is u = gamma_w h. Substituting gamma_w = 9.81 kN/m³ and h = 3.2 m gives u = 9.81 × 3.2. The result is 31.392 kN/m². Since 1 kN/m² equals 1 kPa, the uplift pressure is approximately 31.39 kPa. Determining the residual head itself requires the appropriate seepage analysis for the foundation system. Therefore Option C is correct.
వివరణ:
Question 15
ప్రశ్న 15
What does the term exit gradient mean in the context of a weir founded on permeable alluvium?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Subsurface water flows through the permeable foundation because of the head difference across the weir. Near the downstream end, this seepage flow emerges toward the riverbed or the end of the floor. The hydraulic gradient in this exit region is termed the exit gradient. If it becomes too large relative to the resistance of the foundation soil, particles can be lifted or transported and piping may develop. Safe design therefore requires an adequate downstream floor and cutoff arrangement to keep the exit condition within acceptable limits. Therefore Option B is correct.
వివరణ:
Question 16
ప్రశ్న 16
What primarily governs the required structural thickness of an impervious concrete floor under a weir at a particular location?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Subsurface pressure can exert a substantial upward force on a weir floor. The floor must possess enough weight and structural strength to resist the applicable net uplift together with other loads and load combinations. Uplift varies along the floor, so the required structural thickness need not be identical everywhere. Pressure distribution must first be obtained from the adopted seepage analysis before floor thickness is finalized. Surface-flow design alone cannot establish the necessary floor thickness. Therefore Option B is correct.
వివరణ:
Question 17
ప్రశ్న 17
What is the main hydraulic purpose of the downstream glacis in a sloping-glacis weir?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Overflow leaving the crest possesses considerable energy and accelerates as it moves downstream. The glacis provides a controlled sloping surface along which this high-velocity flow can travel. Its profile and terminal floor level are coordinated with tail-water so that a hydraulic jump can be developed in the protected region. This makes the glacis an integral part of the energy-dissipation system rather than merely a structural ramp. Downstream protection is still required because residual turbulence and scour can extend beyond the rigid floor. Therefore Option B is correct.
వివరణ:
Question 18
ప్రశ్న 18
For a hydraulic jump associated with a sloping-glacis weir, assume the flow immediately before the jump can be treated as rectangular with y1 = 0.80 m and Fr1 = 5.0. Using y2/y1 = 0.5[sqrt(1 + 8Fr1²) - 1], what is the approximate sequent depth y2?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The supplied relation gives y2/y1 = 0.5[sqrt(1 + 8 × 5²) - 1]. The expression under the square root is 201, whose square root is approximately 14.177. The resulting depth ratio is approximately 6.589. Multiplying by y1 = 0.80 m gives y2 ≈ 5.27 m. This conjugate-depth calculation helps assess whether the available tail-water can support the desired hydraulic jump. Therefore Option C is correct.
వివరణ:
Question 19
ప్రశ్న 19
Why is flexible protection commonly provided downstream of the rigid impervious floor of a weir?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The riverbed immediately beyond the rigid floor is exposed to turbulent flow and residual velocity. Some local scour and bed adjustment can therefore occur even after energy dissipation. Flexible protection such as stone or block pitching can settle with moderate scour while continuing to shield the underlying material. This reduces the risk that erosion will progress backward beneath the rigid floor. Its length, size and filter arrangement must be coordinated with expected scour and foundation conditions. Therefore Option B is correct.
వివరణ:
Question 20
ప్రశ్న 20
What is the principal function of an inverted filter near the downstream end of a weir floor or protection system?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Seepage water should be allowed to escape without carrying foundation material with it. An inverted filter is graded so that water can pass through while the underlying soil particles are retained. This helps prevent piping and loss of foundation material at the downstream end. It may be incorporated beneath or with downstream flexible protection according to the design arrangement. The filter therefore complements the impervious floor and cutoff system rather than replacing them. Therefore Option B is correct.
వివరణ:
Question 21
ప్రశ్న 21
Which group most appropriately represents components that may form part of a complete diversion headworks associated with a weir?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A diversion headworks is a system rather than just an isolated overflow wall. The weir or barrage raises and controls the river level. Undersluices and a divide wall can help manage the river flow and sediment near the canal offtake. The canal head regulator controls admission of water into the canal, while fish passage may be required where ecological conditions demand it. Guide banks, protection works and other appurtenances are added according to river and site conditions. Therefore Option A is correct.
వివరణ:
Question 22
ప్రశ్న 22
What is an important function of a divide wall in a diversion headworks?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A divide wall separates the undersluice pocket from the main weir or barrage portion. This separation helps maintain the desired hydraulic behavior near the canal head regulator. It can assist in developing a relatively clear approach channel and in reducing undesirable crosscurrents between adjoining portions of the headworks. The wall can also form part of the arrangement associated with a fish pass or other appurtenances in some layouts. It does not replace the foundation floor or seepage-control cutoffs. Therefore Option A is correct.
వివరణ:
Question 23
ప్రశ్న 23
What is the main function of undersluices provided near the canal head regulator of a diversion weir or barrage?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Undersluices are low-level openings generally located near the canal offtake portion of a diversion headworks. They can pass sediment-laden bottom water and help scour deposited material from the pocket upstream of the canal head regulator. This assists in maintaining a deeper and comparatively clearer approach toward the intake. They also provide additional river waterway under appropriate operating conditions. Their hydraulic and sediment-control role is distinct from that of the canal head regulator itself. Therefore Option B is correct.
వివరణ:
Question 24
ప్రశ్న 24
For a fixed flood discharge, what is an important consequence of reducing the effective waterway of a diversion weir without any compensating change in river conditions?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Discharge intensity is the discharge passing per unit effective width of the structure. If the same total discharge is forced through a smaller waterway, the average discharge intensity increases. Higher intensity can be associated with greater velocities and greater local scour potential downstream. A reduced waterway may also cause increased upstream afflux depending on the hydraulic conditions. Waterway selection must therefore be coordinated with flood passage, scour depth, river training and structural economy rather than minimized indiscriminately. Therefore Option A is correct.
వివరణ:
Question 25
ప్రశ్న 25
Which design approach is most appropriate for a new sloping-glacis weir on a deep permeable alluvial foundation?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A weir on alluvium is affected simultaneously by surface and subsurface hydraulic phenomena. Surface-flow analysis determines matters such as flood passage, afflux, scour and energy dissipation. Subsurface-flow analysis determines uplift pressures, exit gradients and the required arrangement of floors and cutoffs. The downstream glacis and stilling system must also be compatible with the expected tail-water conditions. Safe design therefore requires all of these elements to be coordinated rather than designed independently. Therefore Option B is correct.
వివరణ:
Question 26
ప్రశ్న 26
Consider the following statements about vertical-drop and sloping-glacis weirs: I. A vertical-drop weir has a vertical or nearly vertical downstream face. II. A sloping-glacis weir can be arranged so that a hydraulic jump forms in a protected downstream region. III. Cutoffs and impervious floors are important for seepage and uplift control on permeable foundations. IV. Downstream protection remains necessary because scour can occur beyond the rigid floor. Which option is correct?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Statement I correctly describes the characteristic downstream profile of a traditional vertical-drop weir. Statement II is correct because the glacis and downstream floor of a sloping-glacis structure are coordinated with the desired hydraulic-jump condition. Statement III is correct because seepage through permeable foundations creates uplift and piping concerns that require floor and cutoff treatment. Statement IV is correct because residual energy and local bed adjustment can produce scour beyond the rigid structure. Therefore all four statements are correct and Option D is the valid answer.
వివరణ:
Answer Key సమాధానాల పట్టిక
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Question 1 ప్రశ్న 1Answer: A. To raise the river water level sufficiently to divert the required supply into an off-taking canal or conduit సమాధానం: A.
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Question 2 ప్రశ్న 2Answer: C. It has a raised crest or body wall with a vertical or nearly vertical downstream face and a downstream floor or cistern సమాధానం: C.
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Question 3 ప్రశ్న 3Answer: A. A long sloping surface downstream of the crest leading toward the energy-dissipation floor సమాధానం: A.
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Question 4 ప్రశ్న 4Answer: B. A vertical-drop weir produces an abrupt falling jet, whereas a sloping-glacis weir guides the flow down a glacis and can be proportioned to form a controlled hydraulic jump సమాధానం: B.
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Question 5 ప్రశ్న 5Answer: B. Because it influences the upstream pond level, head available for diversion, overflow head and possible afflux సమాధానం: B.
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Question 6 ప్రశ్న 6Answer: B. 150 m సమాధానం: B.
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Question 7 ప్రశ్న 7Answer: C. Approximately 384.7 m³/s సమాధానం: C.
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Question 8 ప్రశ్న 8Answer: C. Approximately 86.7 m సమాధానం: C.
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Question 9 ప్రశ్న 9Answer: B. RL 102.50 m సమాధానం: B.
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Question 10 ప్రశ్న 10Answer: B. To provide a controlled seepage path and structural floor while helping resist uplift and piping-related foundation failure సమాధానం: B.
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Question 11 ప్రశ్న 11Answer: B. The upstream floor contributes to seepage control and approach-bed protection, while the downstream floor additionally has to accommodate severe overflow, uplift and energy-dissipation effects సమాధానం: B.
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Question 12 ప్రశ్న 12Answer: B. To interrupt and lengthen the subsurface seepage path, influence uplift distribution and help control piping and exit-gradient danger సమాధానం: B.
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Question 13 ప్రశ్న 13Answer: B. Because it can reduce the dangerous seepage gradient near the downstream exit and its depth must also be coordinated with expected scour సమాధానం: B.
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Question 14 ప్రశ్న 14Answer: C. Approximately 31.39 kPa సమాధానం: C.
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Question 15 ప్రశ్న 15Answer: B. The hydraulic gradient of subsurface seepage where it emerges near the downstream end of the floor సమాధానం: B.
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Question 16 ప్రశ్న 16Answer: B. The net uplift pressure and other applicable structural loads relative to the resisting weight and strength of the floor సమాధానం: B.
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Question 17 ప్రశ్న 17Answer: B. To guide the overflowing water smoothly toward the downstream energy-dissipation region and help establish the desired hydraulic-jump condition సమాధానం: B.
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Question 18 ప్రశ్న 18Answer: C. Approximately 5.27 m సమాధానం: C.
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Question 19 ప్రశ్న 19Answer: B. To accommodate local bed adjustment and protect against scour where rigid flooring terminates సమాధానం: B.
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Question 20 ప్రశ్న 20Answer: B. To permit seepage water to escape while preventing migration of the underlying soil particles సమాధానం: B.
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Question 21 ప్రశ్న 21Answer: A. Weir or barrage, undersluices, divide wall, canal head regulator, fish pass where required, and river-training or protection works సమాధానం: A.
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Question 22 ప్రశ్న 22Answer: A. To separate the undersluice portion from the main weir portion and help establish more controlled flow and sediment conditions near the canal head regulator సమాధానం: A.
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Question 23 ప్రశ్న 23Answer: B. To pass low-level and sediment-laden flows and assist in maintaining a comparatively clear approach near the canal offtake సమాధానం: B.
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Question 24 ప్రశ్న 24Answer: A. Discharge intensity generally increases, which can increase velocities, afflux and scour demands సమాధానం: A.
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Question 25 ప్రశ్న 25Answer: B. Coordinate crest and waterway hydraulics, hydraulic-jump energy dissipation, impervious-floor and cutoff layout, uplift, exit-gradient safety, scour and downstream protection సమాధానం: B.
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Question 26 ప్రశ్న 26Answer: D. I, II, III and IV సమాధానం: D.