Please keep at least one language enabled. || కనీసం ఒక భాషను ఎంచుకోండి.
Question 1
ప్రశ్న 1
Which set states the three fundamental safety objectives commonly used in the design of an earth dam?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
An earth dam must first be protected against overtopping because uncontrolled flow over an ordinary earth embankment can cause rapid erosion. Its slopes and foundation must also remain stable under the relevant loading and reservoir conditions. Seepage must be controlled so that piping and internal erosion do not develop within the embankment or foundation. These requirements are explicitly reflected in the basic design framework for earth dams. Therefore Option C is correct.
వివరణ:
Question 2
ప్రశ్న 2
What most accurately describes a homogeneous earth dam?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A homogeneous earth dam is constructed predominantly from one general type of suitable earth material. The word homogeneous describes the principal embankment material rather than requiring every small component to be identical. Filters, drains, riprap, or other protective features may still be incorporated for safety. Internal drainage is especially important where seepage through the main fill would otherwise emerge on the downstream slope. Therefore Option B is correct.
వివరణ:
Question 3
ప్రశ్న 3
Which description best represents a zoned earth dam?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A zoned earth dam deliberately places different materials in different parts of the section. A low-permeability core provides the principal water barrier. More pervious or stronger outer shells can provide structural support and facilitate drainage. Transition and filter zones may be inserted between dissimilar materials to control migration of soil particles. Hence Option A correctly describes a zoned earth dam.
వివరణ:
Question 4
ప్రశ్న 4
In the traditional classification of earth dams, what distinguishes a diaphragm-type section from a zoned section with a broad impervious core?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A diaphragm-type concept uses a comparatively thin impervious barrier as the principal seepage-control element. The surrounding earth or other embankment material supplies most of the structural mass and stability. The diaphragm may be placed near the centre or toward the upstream side depending on the adopted design. This differs conceptually from a zoned earth dam having a relatively broad impervious soil core. Therefore Option D is correct.
వివరణ:
Question 5
ప్రశ్న 5
What is the principal function of the impervious core in a zoned earth dam?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The core is the principal low-permeability zone within a zoned earth dam. Its purpose is to restrict the quantity of water passing through the embankment and to control the seepage path. The core must be integrated with foundation seepage-control measures so that water cannot simply pass underneath or around it. Adjacent filters or transitions are often required to protect the core against internal erosion. Hence Option B is correct.
వివరణ:
Question 6
ప్రశ్న 6
What is the main role of the outer shells, also called casing or shoulders, in a zoned earth dam?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The outer shells form a large part of the embankment mass and contribute strongly to slope stability. They also protect and support the impervious core against deformation and external exposure. Relatively pervious materials can often be used in these zones when they satisfy strength, durability, and filter compatibility requirements. This zoning can make efficient use of locally available materials. Therefore Option C is correct.
వివరణ:
Question 7
ప్రశ్న 7
Which statement best reflects how the cross-section of an earth dam should be selected?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
No single earth-dam cross-section is optimal for every site. The available quantities and properties of borrow materials strongly influence whether a homogeneous or zoned section is economical. Foundation permeability and the feasibility of cutoff construction are also important. Construction equipment, schedule, climate, stability, and seepage behavior can alter the preferred arrangement. Therefore Option D is correct.
వివరణ:
Question 8
ప్రశ్న 8
Which statement about central and upstream-inclined impervious cores is most appropriate?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
An impervious earth core may be arranged centrally or inclined toward the upstream side. The preferred position depends on site geometry, available materials, foundation conditions, diversion arrangements, and construction sequence. A central core can provide favorable contact pressure with the foundation. An inclined core can offer construction or pore-pressure advantages in some layouts. Hence Option A is correct.
వివరణ:
Question 9
ప్రశ్న 9
What are the two essential hydraulic and soil-retention functions of a properly designed filter in an earth dam?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A filter must prevent particles from the protected finer soil from being carried away by seepage. At the same time, it must be sufficiently permeable to permit water to pass without developing excessive hydraulic gradients or pore pressures. These two requirements protect against piping while permitting controlled drainage. A drain that collects and conveys flow must also have adequate discharge capacity. Therefore Option B is correct.
వివరణ:
Question 10
ప్రశ్న 10
What is the principal purpose of an inclined or vertical filter placed immediately downstream of an impervious core?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Seepage that passes through or around the core should not be allowed to emerge uncontrolled within the downstream shell. An inclined or vertical filter intercepts this water along the downstream side of the core. It provides a protected path into the internal drainage system. By lowering the phreatic surface in the downstream part of the embankment, it can improve seepage and stability conditions. Therefore Option C is correct.
వివరణ:
Question 11
ప్రశ్న 11
What is the normal function of a horizontal drainage filter or blanket within the downstream portion of an earth dam?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A horizontal drainage layer receives water from an inclined filter or directly from seepage through the embankment and foundation. It provides a relatively free-draining path toward the downstream side. The collected water is then conveyed to a toe drain or another designed outlet. This helps keep seepage from emerging uncontrolled on the downstream slope. Hence Option D is correct.
వివరణ:
Question 12
ప్రశ్న 12
What is the principal function of a toe drain at the downstream toe of an earth dam?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A toe drain is located near the downstream toe where seepage from internal filters and drainage blankets can be collected. It provides a controlled outlet rather than allowing water to emerge diffusely through the downstream slope. Safe discharge also makes seepage easier to observe and monitor. The drain must be protected against the migration of surrounding soil particles. Therefore Option A is correct.
వివరణ:
Question 13
ప్రశ్న 13
What is a principal function of a rock toe in an earth dam?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A rock toe consists of free-draining coarse material placed at the downstream toe. It helps provide a drainage outlet for seepage reaching the lower part of the embankment. The coarse material can also protect the lower downstream slope from erosion, including effects of tail-water where relevant. It is not a substitute for the impervious core or the complete filter system. Hence Option C is correct.
వివరణ:
Question 14
ప్రశ్న 14
Why is a cutoff trench or cutoff barrier provided beneath an earth dam where the foundation is pervious?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A pervious foundation can allow substantial underseepage beneath an otherwise impervious embankment core. A cutoff increases resistance to this flow by penetrating the pervious foundation with lower-permeability material or another barrier. This can reduce seepage quantity and help control hydraulic gradients toward the downstream toe. The cutoff should be coordinated with the core so that a continuous seepage-control system is formed. Therefore Option B is correct.
వివరణ:
Question 15
ప్రశ్న 15
Which statement correctly distinguishes a full, or positive, cutoff from a partial cutoff?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A full cutoff is intended to penetrate the pervious foundation and connect with an underlying impervious stratum. This provides a more complete barrier to underseepage. A partial cutoff extends only partway through the pervious foundation when full penetration is impractical or uneconomical. Additional measures such as an upstream impervious blanket or downstream pressure-relief system may then be required. Hence Option D is correct.
వివరణ:
Question 16
ప్రశ్న 16
When a full cutoff through a deep pervious foundation is impractical, what is the purpose of an upstream impervious blanket used with suitable downstream seepage-control measures?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
An upstream impervious blanket extends the low-permeability flow path horizontally beneath the reservoir. This lengthens the seepage path through the foundation and can reduce the hydraulic gradient. It is particularly useful when an impervious stratum lies too deep for an economical full cutoff. Because uplift and residual underseepage can still occur downstream, relief or drainage measures may also be necessary. Therefore Option A is correct.
వివరణ:
Question 17
ప్రశ్న 17
What is the primary design purpose of freeboard in an earth dam?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Freeboard is the vertical safety margin between the specified reservoir level and the dam crest. It must be sufficient to prevent wave action and other water-level effects from causing overtopping. Settlement of the embankment and foundation must also be considered so that the required freeboard is not lost with time. Freeboard complements rather than replaces adequate spillway capacity. Hence Option C is correct.
వివరణ:
Question 18
ప్రశ్న 18
The maximum reservoir water level is at elevation 312.5 m and the design crest elevation, excluding any additional camber, is 317.0 m. What is the corresponding freeboard?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Freeboard is measured vertically from the specified maximum reservoir water level to the crest elevation used for the definition. The crest elevation is 317.0 m. The maximum water level is 312.5 m. Their difference is 317.0 - 312.5 = 4.5 m. Therefore Option B is correct.
వివరణ:
Question 19
ప్రశ్న 19
Why may longitudinal camber or settlement allowance be provided at the crest of an earth dam?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Earth embankments and their foundations can continue to compress and settle after construction. If this deformation is ignored, the final crest level may become lower than intended. Reduced crest elevation can reduce the available freeboard and increase overtopping risk. Camber or an added settlement allowance raises the constructed crest by an amount justified by the expected deformation. Therefore Option D is correct.
వివరణ:
Question 20
ప్రశ్న 20
Which slope-protection arrangement is generally appropriate for an earth dam?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The upstream slope is exposed to reservoir waves that can erode unprotected earth materials. Riprap or an equivalent designed protective system is therefore commonly used on that face. The downstream face is more directly exposed to rainfall, runoff, and wind erosion and can often be protected by turfing or another suitable surface treatment. Surface drainage should prevent concentrated runoff from cutting gullies into the slope. Hence Option A is correct.
వివరణ:
Question 21
ప్రశ్న 21
An upstream slope is specified as 3H:1V. What horizontal projection corresponds to a vertical rise of 12 m?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The notation 3H:1V means three units of horizontal distance for every one unit of vertical distance. A vertical rise of 12 m therefore corresponds to a horizontal distance of 3 × 12 m. This equals 36 m. The ratio describes geometry only and does not by itself establish that the slope is stable for a particular soil and loading condition. Therefore Option C is correct.
వివరణ:
Question 22
ప్రశ్న 22
Why can rapid or sudden drawdown of a reservoir be critical for the upstream slope of an earth dam?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Before drawdown, part of the upstream embankment may contain elevated pore-water pressure. If the reservoir falls faster than these pore pressures can dissipate, the external water support acting on the upstream face is removed quickly. The soil mass can therefore experience an unfavorable combination of reduced external support and persistent internal pore pressure. This can make the upstream slope a critical stability case. Hence Option B is correct.
వివరణ:
Question 23
ప్రశ్న 23
Under prolonged full-reservoir conditions with steady seepage, which part of an earth dam commonly requires particular attention in slope-stability analysis?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
During sustained reservoir loading, seepage tends toward a steady pattern through the embankment and foundation. The downstream part of the dam can then contain a phreatic surface and significant pore-water pressures. Higher pore pressure reduces effective stress and can decrease available shear strength. Proper filters and drains are used partly to control this condition, but stability still has to be checked. Therefore Option D is correct.
వివరణ:
Question 24
ప్రశ్న 24
What is the usual stability implication of flattening an earth-dam slope, all other conditions being comparable?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A flatter slope generally reduces the driving tendency of the soil mass and can improve stability. However, flattening increases the horizontal width and volume of the embankment. It may therefore increase land requirements and construction quantities. The final slope must be selected from stability analysis together with seepage, foundation, seismic, and economic considerations. Hence Option A is correct.
వివరణ:
Question 25
ప్రశ్న 25
A proposed earth dam has several usable borrow materials, a pervious foundation, and a reservoir exposed to significant wave action. Which preliminary design concept is most defensible?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Different suitable borrow materials can be used economically by assigning them to zones that match their engineering properties. A low-permeability core can control seepage while stronger or more pervious shells provide support and drainage. Filters and drains should protect against particle migration and safely convey intercepted seepage. The pervious foundation requires an appropriate cutoff, blanket, drainage, or combination of seepage-control measures, and significant wave action requires adequate freeboard and upstream slope protection. Therefore Option C is correct.
వివరణ:
Answer Key సమాధానాల పట్టిక
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Question 1 ప్రశ్న 1Answer: C. Safety against overtopping, adequate stability, and safety against internal erosion సమాధానం: C.
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Question 2 ప్రశ్న 2Answer: B. An earth dam formed predominantly from one general type of earth material, with drainage features added where required సమాధానం: B.
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Question 3 ప్రశ్న 3Answer: A. A dam composed of a relatively impervious core supported by outer zones or shells selected for stability, drainage, and economical use of available materials సమాధానం: A.
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Question 4 ప్రశ్న 4Answer: D. The diaphragm-type section uses a relatively thin impervious barrier supported by the surrounding embankment సమాధానం: D.
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Question 5 ప్రశ్న 5Answer: B. To act as the main low-permeability barrier and limit seepage through the embankment సమాధానం: B.
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Question 6 ప్రశ్న 6Answer: C. To provide structural stability and protect/support the impervious core while allowing economical use of suitable materials సమాధానం: C.
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Question 7 ప్రశ్న 7Answer: D. The choice should consider available materials, foundation and cutoff conditions, construction methods, climate, stability, and seepage requirements సమాధానం: D.
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Question 8 ప్రశ్న 8Answer: A. Core position is a design choice influenced by materials, topography, foundation conditions, and construction considerations సమాధానం: A.
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Question 9 ప్రశ్న 9Answer: B. It should retain the protected soil particles while allowing seepage water to pass relatively freely సమాధానం: B.
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Question 10 ప్రశ్న 10Answer: C. To intercept seepage emerging from the core and keep the downstream shell relatively dry సమాధానం: C.
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Question 11 ప్రశ్న 11Answer: D. To carry intercepted seepage toward the downstream toe drain or other safe outlet సమాధానం: D.
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Question 12 ప్రశ్న 12Answer: A. To collect seepage delivered by the internal drainage system and discharge it safely away from the embankment సమాధానం: A.
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Question 13 ప్రశ్న 13Answer: C. To facilitate drainage near the downstream toe and protect the lower downstream slope, including against tail-water erosion where applicable సమాధానం: C.
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Question 14 ప్రశ్న 14Answer: B. To reduce foundation underseepage and lower the risk of excessive exit gradients, uplift, and piping సమాధానం: B.
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Question 15 ప్రశ్న 15Answer: D. A full cutoff extends to a competent impervious stratum, whereas a partial cutoff terminates within the pervious foundation సమాధానం: D.
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Question 16 ప్రశ్న 16Answer: A. To lengthen the seepage path and reduce hydraulic gradients and underseepage సమాధానం: A.
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Question 17 ప్రశ్న 17Answer: C. To provide vertical margin between the maximum reservoir level and dam crest so that waves, settlement, and related level variations do not cause overtopping సమాధానం: C.
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Question 18 ప్రశ్న 18Answer: B. 4.5 m సమాధానం: B.
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Question 19 ప్రశ్న 19Answer: D. To compensate for anticipated post-construction settlement so that the required final crest level and freeboard are maintained సమాధానం: D.
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Question 20 ప్రశ్న 20Answer: A. Riprap or equivalent erosion-resistant protection on the upstream slope against wave action, and suitable turfing or other erosion protection on the downstream slope against rainfall and surface runoff సమాధానం: A.
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Question 21 ప్రశ్న 21Answer: C. 36 m సమాధానం: C.
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Question 22 ప్రశ్న 22Answer: B. External reservoir support may fall rapidly while high pore-water pressures within the upstream embankment dissipate more slowly సమాధానం: B.
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Question 23 ప్రశ్న 23Answer: D. The downstream slope, because the phreatic surface and seepage pressures can reduce effective stress within the downstream part of the embankment సమాధానం: D.
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Question 24 ప్రశ్న 24Answer: A. It generally improves slope stability but increases embankment footprint and material quantity సమాధానం: A.
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Question 25 ప్రశ్న 25Answer: C. Use zoning to place low-permeability material in the core and stronger or more pervious materials in shells; provide compatible filters and drains, foundation seepage control, adequate freeboard, and upstream erosion protection సమాధానం: C.