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All questions of Seepage Through Soils for Civil Engineering (CE) Exam
The portion between two successive flow lines is known as___________- a)Field channel
- b)Flow channel
- c)Open channel
- d)All of the mentioned
Correct answer is option 'B'. Can you explain this answer?
The portion between two successive flow lines is known as___________
a)
Field channel
b)
Flow channel
c)
Open channel
d)
All of the mentioned
|
Avinash Mehta answered |
Explanation: The portion between any two successive flow lines is called as flow channel and the portion enclosed between two successive equipotential lines and successive flow lines is known as field.
Who was the first to give graphical method of flow net construction?- a)Casagrande
- b)Darcy
- c)Forchheimer
- d)Kozney
Correct answer is option 'C'. Can you explain this answer?
Who was the first to give graphical method of flow net construction?
a)
Casagrande
b)
Darcy
c)
Forchheimer
d)
Kozney
|
Rajat Sen answered |
The graphical method of flow net construction first given by Forchheimer in 1930, based on trial sketching.
If a fully saturated soil mass has a water content of 100%, then its void ratio is _________- a)less than the specific gravity
- b)greater than the specific gravity
- c)equal to specific gravity
- d)does not depend on specific gravity
Correct answer is option 'C'. Can you explain this answer?
If a fully saturated soil mass has a water content of 100%, then its void ratio is _________
a)
less than the specific gravity
b)
greater than the specific gravity
c)
equal to specific gravity
d)
does not depend on specific gravity
|
Pioneer Academy answered |
Given,
Degree of saturation S = 1
water content w = 100%
void ratio e = wG/s
∴ e = 1G/1
∴ e = G.
Degree of saturation S = 1
water content w = 100%
void ratio e = wG/s
∴ e = 1G/1
∴ e = G.
The hydraulic gradient theory of weir design was developed by__________- a)Darcy and Beresford
- b)Col. Clibborn
- c)None of the mentioned
- d)All of the mentioned
Correct answer is option 'A'. Can you explain this answer?
The hydraulic gradient theory of weir design was developed by__________
a)
Darcy and Beresford
b)
Col. Clibborn
c)
None of the mentioned
d)
All of the mentioned
|
Sai Sarkar answered |
In 1902, Col. Clibborn and Beresford developed the hydraulic gradient theory of weir design as a result of their experiment.
The Darcy’s law governing the flow of water through is related to which of the following law?- a)Ohm’s law
- b)Stokes law
- c)Faraday’s law
- d)None of the mentioned
Correct answer is option 'A'. Can you explain this answer?
The Darcy’s law governing the flow of water through is related to which of the following law?
a)
Ohm’s law
b)
Stokes law
c)
Faraday’s law
d)
None of the mentioned
|
Sagarika Patel answered |
Darcy's law is an equation that describes the flow of a fluid through a porous medium. The law was formulated by Henry Darcy based on the results of experiments on the flow of water through beds of sand, forming the basis of hydrogeology, a branch of earth sciences. Darcy's law was determined experimentally by Darcy. It has since been derived from the Navier–Stokes equations via homogenization. It is analogous to Fourier's law in the field of heat conduction, Ohm's law in the field of electrical networks, or Fick's law in diffusion theory.
One application of Darcy's law is to analyze water flow through an aquifer; Darcy's law along with the equation of conservation of mass are equivalent to the groundwater flow equation, one of the basic relationships of hydrogeology.
The hydrostatic pressure in terms of piezometric head can be calculated from which of the following equation?- a)hW=h – Z
- b)hW=h + Z
- c)hW =u/γW
- d)hW=h/z
Correct answer is option 'A'. Can you explain this answer?
The hydrostatic pressure in terms of piezometric head can be calculated from which of the following equation?
a)
hW=h – Z
b)
hW=h + Z
c)
hW =u/γW
d)
hW=h/z
|
Charvi Kaur answered |
The equation hW=h – Z ,can be used to plot pressure net representing lines of equal water pressure without the saturated soil mass since all the three quantities in the equation can be expressed a the percentage of total hydraulic head H.
The path along which ,the individual particles of water seep through the soil are___________- a)Stream lines and Flow lines
- b)Equipotential lines
- c)None of the mentioned
- d)All of the mentioned
Correct answer is option 'A'. Can you explain this answer?
The path along which ,the individual particles of water seep through the soil are___________
a)
Stream lines and Flow lines
b)
Equipotential lines
c)
None of the mentioned
d)
All of the mentioned
|
Kiran Gupta answered |
The direction of seepage is always perpendicular to the equipotential line. But both equipotential line and stream line (flow line) is mutually orthogonal .So the individual particle of the water seep through stream line.
The upstream slope of an earth dam under steady seepage condition is- a)equipotential line
- b)phreatic line
- c)flow line
- d)seepage line
Correct answer is option 'A'. Can you explain this answer?
The upstream slope of an earth dam under steady seepage condition is
a)
equipotential line
b)
phreatic line
c)
flow line
d)
seepage line
|
|
Aditya Deshmukh answered |
An equipotential line is a line in a field of force that represents points of equal potential energy. In other words, points along an equipotential line have the same potential energy, regardless of the direction in which they are moving.
Equipotential lines are often used to represent the distribution of electric potential in a circuit or the gravitational potential of a planet or other celestial body. They are also used in other fields, such as fluid dynamics and thermodynamics, to represent the distribution of other types of potential energy.
Equipotential lines are often depicted on maps or diagrams and can be used to visualize the flow of energy in a system. They are typically drawn perpendicular to the direction of the force field, and the spacing between the lines indicates the strength of the field.
Water is flowing in an upward direction through a stratum of sand, 4 m thick, under a total head difference of 2 m. The sand has a specific gr. of 2.65 and void ratio of 0.065. The factor of safety against quick sand condition would be
- a)3.0
- b)1.0
- c)1.5
- d)2.0
Correct answer is option 'A'. Can you explain this answer?
Water is flowing in an upward direction through a stratum of sand, 4 m thick, under a total head difference of 2 m. The sand has a specific gr. of 2.65 and void ratio of 0.065. The factor of safety against quick sand condition would be
a)
3.0
b)
1.0
c)
1.5
d)
2.0
|
|
Puja Sharma answered |
What are the essentials, required to draw a flow net?- a)Top Flow and Phreatic line
- b)Stream line
- c)None of the mentioned
- d)All of the mentioned
Correct answer is option 'A'. Can you explain this answer?
What are the essentials, required to draw a flow net?
a)
Top Flow and Phreatic line
b)
Stream line
c)
None of the mentioned
d)
All of the mentioned
|
Kritika Shah answered |
Drawing a flow net is an essential step in solving problems related to seepage through soil. A flow net provides a graphical representation of flow lines and equipotential lines, which help in understanding the flow patterns and calculating quantities such as seepage velocity and discharge. In order to draw a flow net, the following essentials are required:
a) Top Flow and Phreatic Line:
The top flow line represents the free water surface above the soil, while the phreatic line represents the water table within the soil. These lines are important in defining the boundaries and constraints of the flow net. The top flow line is usually horizontal and parallel to the base of the soil, while the phreatic line follows the path of least resistance.
b) Streamlines:
Streamlines are imaginary lines that represent the flow direction of water within the soil. They are drawn perpendicular to the equipotential lines and are used to determine the flow pattern and paths. Streamlines do not intersect each other and are evenly spaced.
The flow net consists of a series of flow channels bounded by streamlines and equipotential lines. The flow channels represent zones of constant flow and are used to calculate the flow rate through the soil.
c) Equipotential lines:
Equipotential lines are imaginary lines that connect points of equal hydraulic potential. They are drawn parallel to the direction of flow and help in understanding the variation in head or pressure within the soil. Equipotential lines intersect streamlines at right angles.
The spacing between equipotential lines represents the hydraulic gradient and can be used to calculate the seepage velocity. Closer spacing indicates a steeper gradient and faster flow.
d) All of the mentioned:
While options a) and b) are the most essential elements required to draw a flow net, it is important to note that option d) "All of the mentioned" is also correct. This is because both streamlines and equipotential lines are necessary to accurately represent the flow patterns and calculate the relevant quantities. However, if we strictly consider the bare minimum essentials, option a) "Top Flow and Phreatic Line" is sufficient.
In conclusion, the essentials required to draw a flow net include the top flow and phreatic line, which define the boundaries, and streamlines and equipotential lines, which represent the flow direction and hydraulic potential within the soil.
a) Top Flow and Phreatic Line:
The top flow line represents the free water surface above the soil, while the phreatic line represents the water table within the soil. These lines are important in defining the boundaries and constraints of the flow net. The top flow line is usually horizontal and parallel to the base of the soil, while the phreatic line follows the path of least resistance.
b) Streamlines:
Streamlines are imaginary lines that represent the flow direction of water within the soil. They are drawn perpendicular to the equipotential lines and are used to determine the flow pattern and paths. Streamlines do not intersect each other and are evenly spaced.
The flow net consists of a series of flow channels bounded by streamlines and equipotential lines. The flow channels represent zones of constant flow and are used to calculate the flow rate through the soil.
c) Equipotential lines:
Equipotential lines are imaginary lines that connect points of equal hydraulic potential. They are drawn parallel to the direction of flow and help in understanding the variation in head or pressure within the soil. Equipotential lines intersect streamlines at right angles.
The spacing between equipotential lines represents the hydraulic gradient and can be used to calculate the seepage velocity. Closer spacing indicates a steeper gradient and faster flow.
d) All of the mentioned:
While options a) and b) are the most essential elements required to draw a flow net, it is important to note that option d) "All of the mentioned" is also correct. This is because both streamlines and equipotential lines are necessary to accurately represent the flow patterns and calculate the relevant quantities. However, if we strictly consider the bare minimum essentials, option a) "Top Flow and Phreatic Line" is sufficient.
In conclusion, the essentials required to draw a flow net include the top flow and phreatic line, which define the boundaries, and streamlines and equipotential lines, which represent the flow direction and hydraulic potential within the soil.
In homogeneous soil ,every transition in the shape of curves drawn in flow net must be____________- a)Smooth
- b)Sharp
- c)Rough
- d)All of the mentioned
Correct answer is option 'A'. Can you explain this answer?
In homogeneous soil ,every transition in the shape of curves drawn in flow net must be____________
a)
Smooth
b)
Sharp
c)
Rough
d)
All of the mentioned
|
|
Anshul Kumar answered |
According to practical suggestion given by A.Casagrande, every transition in the shape of curve is smooth, being either elliptical or parabolic in shape.
The loss of head per unit distance in soil is called___________- a)Velocity potential
- b)Hydraulic gradient
- c)Velocity gradient
- d)Stream function
Correct answer is option 'B'. Can you explain this answer?
The loss of head per unit distance in soil is called___________
a)
Velocity potential
b)
Hydraulic gradient
c)
Velocity gradient
d)
Stream function
|
|
Aarav Chauhan answered |
The loss of head or the dissipation of the hydraulic head per unit distance of flow through the soil is called hydraulic gradient
i.e. i=h/L.
i.e. i=h/L.
Darcy’s law for flow through soil is valid if Reynold's number is less than- a)4000
- b)3000
- c)2000
- d)1
Correct answer is option 'D'. Can you explain this answer?
Darcy’s law for flow through soil is valid if Reynold's number is less than
a)
4000
b)
3000
c)
2000
d)
1
|
|
Mehul Choudhury answered |
Darcy's law is valid if the flow through soil is laminar and Reynolds number is less than 1.
A hydraulic structure should not be built on pervious soil, because of_________- a)Higher water level at the upstream of the structure
- b)Compressibility of the soil is low
- c)Excessive water pressure above the soil
- d)None of the mentioned
Correct answer is option 'A'. Can you explain this answer?
A hydraulic structure should not be built on pervious soil, because of_________
a)
Higher water level at the upstream of the structure
b)
Compressibility of the soil is low
c)
Excessive water pressure above the soil
d)
None of the mentioned
|
|
Subhankar Khanna answered |
If a hydraulic structure is built on pervious soil, the higher water level at the upstream of the structure will cause seepage through the permeable soil.
During seepage through an earth mass, the direction of seepage is- a)parallel to the equipotential lines
- b)perpendicular to the stream lines
- c)perpendicular to the equipotential lines
- d)along the direction of gravity
Correct answer is option 'C'. Can you explain this answer?
During seepage through an earth mass, the direction of seepage is
a)
parallel to the equipotential lines
b)
perpendicular to the stream lines
c)
perpendicular to the equipotential lines
d)
along the direction of gravity
|
|
Avinash Mehta answered |
During seepage through an earth mass, the direction of seepage is perpendicular to the equipotential lines.
When water flows through an earth mass such as soil or rock, it follows the path of least resistance. This path is determined by the distribution of pore water pressure and water potential in the earth mass.
The equipotential lines are lines of constant water potential, they are perpendicular to the flow direction. The flow direction is perpendicular to the gradient of the equipotential lines, which means that it is parallel to the streamlines or lines of flow. It is always perpendicular to the equipotential lines
Seepage also follows the direction of gravity, as water will flow downhill as long as the gravitational force is greater than the opposing forces such as capillarity, friction, and pressure.
Consider the following statements:
1. Seepage force is applied by flowing water to the soil skeleton through frictional drag.
2. The magnitude of seepage force per unit volume of soil at any point is equal to Yw/i, where Yw is the unit weight of water and i is the hydraulic gradient at that point.
3. In a soil mass subjected to upward flow of water, quick sand condition develops when pore pressure is equal to the total stressWhich of these statements is/are correct?- a)1 and 2
- b)1 and 3
- c)1 only
- d)2 and 3
Correct answer is option 'B'. Can you explain this answer?
Consider the following statements:
1. Seepage force is applied by flowing water to the soil skeleton through frictional drag.
2. The magnitude of seepage force per unit volume of soil at any point is equal to Yw/i, where Yw is the unit weight of water and i is the hydraulic gradient at that point.
3. In a soil mass subjected to upward flow of water, quick sand condition develops when pore pressure is equal to the total stress
1. Seepage force is applied by flowing water to the soil skeleton through frictional drag.
2. The magnitude of seepage force per unit volume of soil at any point is equal to Yw/i, where Yw is the unit weight of water and i is the hydraulic gradient at that point.
3. In a soil mass subjected to upward flow of water, quick sand condition develops when pore pressure is equal to the total stress
Which of these statements is/are correct?
a)
1 and 2
b)
1 and 3
c)
1 only
d)
2 and 3
|
|
Nishanth Banerjee answered |
Seepage force is due to frictional drag and its magnitude is given by iYw per unit volume of soil. For quick condition during upward flow.
Effective stress = total stress - pore pressure So statement 1 and 3 is correct.
Effective stress = total stress - pore pressure So statement 1 and 3 is correct.
A flownet of a coffer dam foundation has 6 flow channels and 18 equipotential drops. The head of water lost during seepage is 6 m. If the coefficient of permeability of foundation is 4 x 10-5 m/min, then the seepage loss per metre length of dam will be- a)2.16 x 10-2 m3/day
- b)6.48 x 10-2 m3/day
- c)11.52 x 10-2 m3/day
- d)34.56 x10-2m3/day
Correct answer is option 'C'. Can you explain this answer?
A flownet of a coffer dam foundation has 6 flow channels and 18 equipotential drops. The head of water lost during seepage is 6 m. If the coefficient of permeability of foundation is 4 x 10-5 m/min, then the seepage loss per metre length of dam will be
a)
2.16 x 10-2 m3/day
b)
6.48 x 10-2 m3/day
c)
11.52 x 10-2 m3/day
d)
34.56 x10-2m3/day
|
|
Mahesh Nair answered |
Seepage loss per metre length,
The flow lines and equipotential lines are____________- a)Parallel
- b)Perpendicular
- c)Elliptical
- d)All of the mentioned
Correct answer is option 'B'. Can you explain this answer?
The flow lines and equipotential lines are____________
a)
Parallel
b)
Perpendicular
c)
Elliptical
d)
All of the mentioned
|
|
Sahil Chawla answered |
The flow lines and equipotential lines always meet at right angles to one another.
The phreatic line can be located by which of the following method?- a)Graphical method
- b)Experimental method
- c)Analytical method
- d)All of the mentioned
Correct answer is option 'D'. Can you explain this answer?
The phreatic line can be located by which of the following method?
a)
Graphical method
b)
Experimental method
c)
Analytical method
d)
All of the mentioned
|
|
Shounak Saini answered |
The phreatic line is the boundary between the saturated and unsaturated zones in the ground. It represents the water table, which is the level at which the soil or rock is completely saturated with water. Determining the location of the phreatic line is important in various civil engineering projects such as designing foundations, excavations, and groundwater management.
There are several methods used to locate the phreatic line, and the correct answer is option 'D', which states that all of the mentioned methods can be used. Let's discuss each method in detail:
a) Graphical Method:
The graphical method involves plotting the water table elevations at various locations on a graph or map. This can be done by using data from monitoring wells or piezometers. By connecting the points of equal elevation, a contour map of the water table can be created. The phreatic line can then be identified as the contour line that represents the boundary between the saturated and unsaturated zones.
b) Experimental Method:
The experimental method involves conducting field tests to directly measure the water table elevation. One common technique is the installation of monitoring wells or piezometers, which are instruments used to measure the groundwater level. By measuring the water level in these wells at different locations, the elevation of the phreatic line can be determined.
c) Analytical Method:
The analytical method involves using mathematical equations and models to estimate the water table elevation. This method relies on various factors such as soil properties, groundwater flow, and boundary conditions. Analytical solutions can be derived from groundwater flow equations, and these solutions can be used to estimate the position of the phreatic line.
By using a combination of these methods, engineers and hydrologists can accurately locate the phreatic line and understand the behavior of groundwater in a particular area. It is important to note that the choice of method depends on the site conditions, available data, and project requirements.
There are several methods used to locate the phreatic line, and the correct answer is option 'D', which states that all of the mentioned methods can be used. Let's discuss each method in detail:
a) Graphical Method:
The graphical method involves plotting the water table elevations at various locations on a graph or map. This can be done by using data from monitoring wells or piezometers. By connecting the points of equal elevation, a contour map of the water table can be created. The phreatic line can then be identified as the contour line that represents the boundary between the saturated and unsaturated zones.
b) Experimental Method:
The experimental method involves conducting field tests to directly measure the water table elevation. One common technique is the installation of monitoring wells or piezometers, which are instruments used to measure the groundwater level. By measuring the water level in these wells at different locations, the elevation of the phreatic line can be determined.
c) Analytical Method:
The analytical method involves using mathematical equations and models to estimate the water table elevation. This method relies on various factors such as soil properties, groundwater flow, and boundary conditions. Analytical solutions can be derived from groundwater flow equations, and these solutions can be used to estimate the position of the phreatic line.
By using a combination of these methods, engineers and hydrologists can accurately locate the phreatic line and understand the behavior of groundwater in a particular area. It is important to note that the choice of method depends on the site conditions, available data, and project requirements.
Undermining of the subsoil is due to __________- a)Seepage
- b)Piping
- c)Excessive water pressure
- d)Uplift pressure
Correct answer is option 'B'. Can you explain this answer?
Undermining of the subsoil is due to __________
a)
Seepage
b)
Piping
c)
Excessive water pressure
d)
Uplift pressure
|
|
Ashwin Desai answered |
Undermining of the subsoil is due to Piping
What are the types of flow head that exist at any point in a saturated soil mass?- a)Piezometric head or pressure head
- b)Velocity head
- c)Position head
- d)All of the mentioned
Correct answer is option 'D'. Can you explain this answer?
What are the types of flow head that exist at any point in a saturated soil mass?
a)
Piezometric head or pressure head
b)
Velocity head
c)
Position head
d)
All of the mentioned
|
Rahul Chatterjee answered |
When water flows through a saturated soil mass ,the total head at any point in the soil mass consist of
i)piezometric head or pressure head
ii) the velocity y head iii)the position head.
i)piezometric head or pressure head
ii) the velocity y head iii)the position head.
To provide safety against piping failure, with a factor of safety of 5, what should be the maximum permissible exit gradient for soil with specific gravity of 2.5 and porosity of 0.35?- a)0.155
- b)0.167
- c)o.i 95 J
- d)0.213
Correct answer is option 'C'. Can you explain this answer?
To provide safety against piping failure, with a factor of safety of 5, what should be the maximum permissible exit gradient for soil with specific gravity of 2.5 and porosity of 0.35?
a)
0.155
b)
0.167
c)
o.i 95 J
d)
0.213
|
|
Yash Joshi answered |
∴ Maximum permissible exit gradient,
For an anisotropic soil, the permeability in the horizontal and vertical direction are kx and ky respectively. What will be the effective permeability of the soil?- a)kx + ky
- b)kxky
- c)√(kxky)
- d)kx/ky
Correct answer is option 'C'. Can you explain this answer?
For an anisotropic soil, the permeability in the horizontal and vertical direction are kx and ky respectively. What will be the effective permeability of the soil?
a)
kx + ky
b)
kxky
c)
√(kxky)
d)
kx/ky
|
Sanvi Kapoor answered |
For an anisotropic soil, kx ≠ ky. Therefore, the effective permeability of the soil is given by k’=√(kxky).
Capillary rise is maximum for- a)coarse grained soils
- b)fine grained soils
- c)well graded soils
- d)gap graded soils
Correct answer is option 'B'. Can you explain this answer?
Capillary rise is maximum for
a)
coarse grained soils
b)
fine grained soils
c)
well graded soils
d)
gap graded soils
|
|
Aditi Chakraborty answered |
For fine grained soils effective size ‘d’ is smaller so it will experience more capillary rise.
Which one of the following explains the flow condition occurring within a soil when its effective pressure is reduced to zero?- a)Laminar flow condition
- b)Quicksand condition
- c)Liquefaction condition
- d)Stratified flow condition
Correct answer is option 'B,C'. Can you explain this answer?
Which one of the following explains the flow condition occurring within a soil when its effective pressure is reduced to zero?
a)
Laminar flow condition
b)
Quicksand condition
c)
Liquefaction condition
d)
Stratified flow condition
|
|
Anand Mehta answered |
When the seepage of water is upward in a soil layer so much that seepage force decreases the inter particle forces and effective stress is reduced to zero, quick sand condition occurs. Liquefaction of sand is also a phenomenon when effective stress of soil is reduced to zero, it usually occurs when sand deposit is shaken due to an earthquake or any other oscillatory load which increases the pore water pressure.
According to theory of flow of fluids through porous medium ,the saturated porous medium is___________- a)Compressible
- b)Incompressible
- c)Moderately compressible
- d)Highly compressible
Correct answer is option 'B'. Can you explain this answer?
According to theory of flow of fluids through porous medium ,the saturated porous medium is___________
a)
Compressible
b)
Incompressible
c)
Moderately compressible
d)
Highly compressible
|
Athul Das answered |
Introduction:
The theory of flow of fluids through a porous medium is an important concept in civil engineering and hydrogeology. It helps in understanding the movement of fluids such as water, oil, or gas through porous materials like soil, sand, or rock. One key characteristic of the saturated porous medium is its compressibility or the ability to change volume under the influence of external forces.
Explanation:
The correct answer to the question is option 'B': Incompressible. Here's why:
Definition of a saturated porous medium:
A saturated porous medium refers to a material (such as soil or rock) that is completely filled with a fluid (such as water). The pores within the medium are filled with the fluid, and the fluid pressure is equal throughout the medium. In this state, the medium is at its maximum capacity to hold the fluid.
Compressibility of fluids:
Fluids can be broadly classified into two categories based on their compressibility:
1. Incompressible fluids: These fluids have negligible changes in volume under the influence of external forces. Liquids, such as water, are considered incompressible because their volume does not change significantly with changes in pressure.
2. Compressible fluids: These fluids can undergo significant changes in volume under the influence of external forces. Gases, such as air, are compressible because their volume can change significantly with changes in pressure.
Compressibility of saturated porous medium:
When a fluid flows through a saturated porous medium, the medium itself does not significantly change its volume. The fluid fills the pores within the medium, and the overall volume of the medium remains constant. Therefore, the saturated porous medium is considered incompressible.
Significance of incompressibility:
The assumption of incompressibility is commonly used in the theory of flow through porous media. It simplifies the mathematical equations and allows for the accurate prediction of fluid behavior within the medium. This assumption is valid for most practical engineering applications involving fluid flow through saturated porous media.
Conclusion:
In conclusion, according to the theory of flow of fluids through porous media, the saturated porous medium is considered incompressible. This means that the volume of the medium does not significantly change when fluid flows through it. This assumption of incompressibility simplifies the mathematical modeling and analysis of fluid flow in porous media.
The theory of flow of fluids through a porous medium is an important concept in civil engineering and hydrogeology. It helps in understanding the movement of fluids such as water, oil, or gas through porous materials like soil, sand, or rock. One key characteristic of the saturated porous medium is its compressibility or the ability to change volume under the influence of external forces.
Explanation:
The correct answer to the question is option 'B': Incompressible. Here's why:
Definition of a saturated porous medium:
A saturated porous medium refers to a material (such as soil or rock) that is completely filled with a fluid (such as water). The pores within the medium are filled with the fluid, and the fluid pressure is equal throughout the medium. In this state, the medium is at its maximum capacity to hold the fluid.
Compressibility of fluids:
Fluids can be broadly classified into two categories based on their compressibility:
1. Incompressible fluids: These fluids have negligible changes in volume under the influence of external forces. Liquids, such as water, are considered incompressible because their volume does not change significantly with changes in pressure.
2. Compressible fluids: These fluids can undergo significant changes in volume under the influence of external forces. Gases, such as air, are compressible because their volume can change significantly with changes in pressure.
Compressibility of saturated porous medium:
When a fluid flows through a saturated porous medium, the medium itself does not significantly change its volume. The fluid fills the pores within the medium, and the overall volume of the medium remains constant. Therefore, the saturated porous medium is considered incompressible.
Significance of incompressibility:
The assumption of incompressibility is commonly used in the theory of flow through porous media. It simplifies the mathematical equations and allows for the accurate prediction of fluid behavior within the medium. This assumption is valid for most practical engineering applications involving fluid flow through saturated porous media.
Conclusion:
In conclusion, according to the theory of flow of fluids through porous media, the saturated porous medium is considered incompressible. This means that the volume of the medium does not significantly change when fluid flows through it. This assumption of incompressibility simplifies the mathematical modeling and analysis of fluid flow in porous media.
The exit gradient can be expressed by which of the following expression?
- a)ie =Δh/i
- b)ie =Δ h.i
- c)ie =l/h
- d)ie =h/i
Correct answer is option 'A'. Can you explain this answer?
The exit gradient can be expressed by which of the following expression?
a)
ie =Δh/i
b)
ie =Δ h.i
c)
ie =l/h
d)
ie =h/i
|
Swara Dasgupta answered |
ie =Δh/i, represent gradient formula where Δ h=potential drop and l is the average of last field in the flow net at exit end.
A flow net can be used for which of the following purpose?- a)Determination of seepage
- b)Determination of seepage pressure
- c)Determination of hydrostatic pressure
- d)All of the mentioned
Correct answer is option 'D'. Can you explain this answer?
A flow net can be used for which of the following purpose?
a)
Determination of seepage
b)
Determination of seepage pressure
c)
Determination of hydrostatic pressure
d)
All of the mentioned
|
Bijoy Kapoor answered |
A flow net is a graphical representation of two-dimensional steady-state groundwater flow through aquifers. Construction of a flownet is often used for solving groundwater flow problems where the geometry makes analytical solutions impractical.
The seepage medium can be replaced by____________electric model having the same geometric shape.- a)Potential divider
- b)Insulator
- c)Electric conductor
- d)Potentiometer
Correct answer is option 'C'. Can you explain this answer?
The seepage medium can be replaced by____________electric model having the same geometric shape.
a)
Potential divider
b)
Insulator
c)
Electric conductor
d)
Potentiometer
|
|
Niharika Yadav answered |
The seepage medium is replaced by an electric conductor consisting of water with some salt or dilute hydrochloric acid.
If the effective permeability k’ is 6*10-7cm/s and ky = 4*10-7cm/s, then kx is equal to ________- a)6*10-7cm/s
- b)7*10-7cm/s
- c)8*10-7cm/s
- d)9*10-7cm/s
Correct answer is option 'D'. Can you explain this answer?
If the effective permeability k’ is 6*10-7cm/s and ky = 4*10-7cm/s, then kx is equal to ________
a)
6*10-7cm/s
b)
7*10-7cm/s
c)
8*10-7cm/s
d)
9*10-7cm/s
|
Lavanya Menon answered |
Given,
k’ = 6*10-7cm/s
ky = 4*10-7cm/s
k’ = √(kxky)
6*10-7 = √(4*10-7* kx)
∴ kx = 9*10-7cm/s.
k’ = 6*10-7cm/s
ky = 4*10-7cm/s
k’ = √(kxky)
6*10-7 = √(4*10-7* kx)
∴ kx = 9*10-7cm/s.
From a flow net which of the following information can be obtained?
1. Rate of flow
2. Pore water pressure
3. Exit gradient
4. Permeability
Select the correct answer using the codes given below:- a)1, 2, 3 and 4
- b)1, 2 and 3 only
- c)2, 3 and 4 only
- d)1 only
Correct answer is option 'B'. Can you explain this answer?
From a flow net which of the following information can be obtained?
1. Rate of flow
2. Pore water pressure
3. Exit gradient
4. Permeability
Select the correct answer using the codes given below:
1. Rate of flow
2. Pore water pressure
3. Exit gradient
4. Permeability
Select the correct answer using the codes given below:
a)
1, 2, 3 and 4
b)
1, 2 and 3 only
c)
2, 3 and 4 only
d)
1 only
|
|
Bhargavi Sengupta answered |
Seepage pressures, uplift pressures, exit gradient and pore-water pressure can be obtained from a flownet.
The coefficient of permeability is 6*10-7cm/s for a soil with a certain liquid. If the viscosity is reduced to half, then the coefficient of permeability is __________- a)6*10-7cm/s
- b)17*10-7cm/s
- c)8*10-7cm/s
- d)12*10-7cm/s
Correct answer is option 'D'. Can you explain this answer?
The coefficient of permeability is 6*10-7cm/s for a soil with a certain liquid. If the viscosity is reduced to half, then the coefficient of permeability is __________
a)
6*10-7cm/s
b)
17*10-7cm/s
c)
8*10-7cm/s
d)
12*10-7cm/s
|
|
Bhaskar Mukherjee answered |
The coefficient of permeability is a measure of the ability of a soil or other porous material to allow fluids to flow through it. It is typically denoted by the symbol k and has units of velocity, such as cm/s or m/s. In this question, we are given that the coefficient of permeability is 6*10^-7 cm/s for a soil with a certain liquid.
The viscosity of a liquid is a measure of its resistance to flow. When the viscosity of a liquid is reduced, it means that the liquid becomes less resistant to flow. In this question, we are told that the viscosity is reduced to half.
When the viscosity of a liquid is reduced, it means that the liquid can flow more easily through the soil or porous material. As a result, the coefficient of permeability increases.
Let's calculate the new coefficient of permeability when the viscosity is reduced to half.
Given:
Coefficient of permeability (k) = 6*10^-7 cm/s
Viscosity is reduced to half
To find the new coefficient of permeability, we can use the following equation:
k2 = k1 * (μ2/μ1)
Where:
k2 = new coefficient of permeability
k1 = original coefficient of permeability
μ2 = new viscosity
μ1 = original viscosity
In this case, since the viscosity is reduced to half, we can substitute μ2 with 0.5μ1 in the equation:
k2 = k1 * (0.5μ1/μ1)
Simplifying the equation:
k2 = k1 * 0.5
Substituting the given value for k1:
k2 = 6*10^-7 cm/s * 0.5
k2 = 3*10^-7 cm/s
Therefore, the new coefficient of permeability when the viscosity is reduced to half is 3*10^-7 cm/s.
However, none of the provided options match this calculated value. Therefore, it seems there may be an error in the given options or the correct answer was not provided.
The viscosity of a liquid is a measure of its resistance to flow. When the viscosity of a liquid is reduced, it means that the liquid becomes less resistant to flow. In this question, we are told that the viscosity is reduced to half.
When the viscosity of a liquid is reduced, it means that the liquid can flow more easily through the soil or porous material. As a result, the coefficient of permeability increases.
Let's calculate the new coefficient of permeability when the viscosity is reduced to half.
Given:
Coefficient of permeability (k) = 6*10^-7 cm/s
Viscosity is reduced to half
To find the new coefficient of permeability, we can use the following equation:
k2 = k1 * (μ2/μ1)
Where:
k2 = new coefficient of permeability
k1 = original coefficient of permeability
μ2 = new viscosity
μ1 = original viscosity
In this case, since the viscosity is reduced to half, we can substitute μ2 with 0.5μ1 in the equation:
k2 = k1 * (0.5μ1/μ1)
Simplifying the equation:
k2 = k1 * 0.5
Substituting the given value for k1:
k2 = 6*10^-7 cm/s * 0.5
k2 = 3*10^-7 cm/s
Therefore, the new coefficient of permeability when the viscosity is reduced to half is 3*10^-7 cm/s.
However, none of the provided options match this calculated value. Therefore, it seems there may be an error in the given options or the correct answer was not provided.
For the water flowing above an impervious ,infinite ,horizontal plane .the net flow is given by___________- a)Casagrande
- b)Kozney
- c)Forchheimer
- d)Darcy
Correct answer is option 'A'. Can you explain this answer?
For the water flowing above an impervious ,infinite ,horizontal plane .the net flow is given by___________
a)
Casagrande
b)
Kozney
c)
Forchheimer
d)
Darcy
|
|
Naina Das answered |
Water Flowing above an Impervious, Infinite, Horizontal Plane
The net flow of water above an impervious, infinite, horizontal plane can be determined using the Casagrande method.
Casagrande Method
The Casagrande method is based on the concept of a flow net, which is a graphical representation of the flow of water through a porous medium. In this method, flow nets are constructed to visualize and analyze the flow patterns and determine the net flow.
Flow Net
A flow net consists of a series of flow channels and equipotential lines. The flow channels represent the flow of water, and the equipotential lines connect points with the same hydraulic head. The flow channels and equipotential lines intersect at right angles.
Construction of Flow Net
To construct a flow net, the following steps are followed:
1. Determine the boundary conditions: The boundaries of the flow domain are defined, including the impervious, infinite, horizontal plane.
2. Assign a known hydraulic head: A known hydraulic head is assigned at a point within the flow domain. This could be at the water surface or at a specific point within the flow.
3. Draw equipotential lines: Equipotential lines are drawn connecting points with the same hydraulic head. The spacing between equipotential lines is determined based on the desired level of accuracy.
4. Draw flow channels: Flow channels are drawn perpendicular to the equipotential lines. The spacing between flow channels is determined based on the desired level of accuracy.
5. Analyze the flow pattern: By observing the flow channels and equipotential lines, the flow pattern can be determined. The net flow of water can be calculated by considering the number of flow channels crossing a specific boundary.
Net Flow Calculation
In the case of water flowing above an impervious, infinite, horizontal plane, the flow channels will be parallel to the plane. The net flow can be calculated by counting the number of flow channels crossing the boundary representing the impervious plane.
Therefore, the correct option for the net flow of water in this scenario is option 'A' - Casagrande method.
The net flow of water above an impervious, infinite, horizontal plane can be determined using the Casagrande method.
Casagrande Method
The Casagrande method is based on the concept of a flow net, which is a graphical representation of the flow of water through a porous medium. In this method, flow nets are constructed to visualize and analyze the flow patterns and determine the net flow.
Flow Net
A flow net consists of a series of flow channels and equipotential lines. The flow channels represent the flow of water, and the equipotential lines connect points with the same hydraulic head. The flow channels and equipotential lines intersect at right angles.
Construction of Flow Net
To construct a flow net, the following steps are followed:
1. Determine the boundary conditions: The boundaries of the flow domain are defined, including the impervious, infinite, horizontal plane.
2. Assign a known hydraulic head: A known hydraulic head is assigned at a point within the flow domain. This could be at the water surface or at a specific point within the flow.
3. Draw equipotential lines: Equipotential lines are drawn connecting points with the same hydraulic head. The spacing between equipotential lines is determined based on the desired level of accuracy.
4. Draw flow channels: Flow channels are drawn perpendicular to the equipotential lines. The spacing between flow channels is determined based on the desired level of accuracy.
5. Analyze the flow pattern: By observing the flow channels and equipotential lines, the flow pattern can be determined. The net flow of water can be calculated by considering the number of flow channels crossing a specific boundary.
Net Flow Calculation
In the case of water flowing above an impervious, infinite, horizontal plane, the flow channels will be parallel to the plane. The net flow can be calculated by counting the number of flow channels crossing the boundary representing the impervious plane.
Therefore, the correct option for the net flow of water in this scenario is option 'A' - Casagrande method.
The total head at any point on a soil may be regarded as__________per unit weight of water measured.- a)Velocity energy
- b)Hydraulic potential
- c)Potential energy
- d)Piezometric energy
Correct answer is option 'B'. Can you explain this answer?
The total head at any point on a soil may be regarded as__________per unit weight of water measured.
a)
Velocity energy
b)
Hydraulic potential
c)
Potential energy
d)
Piezometric energy
|
|
Aarav Chauhan answered |
Flow occurs between two points only when there is a difference in the potential energies or simply potential.
Seepage pressure is important for which of the following purpose?- a)Stability analysis
- b)Structral arrangement
- c)Total head
- d)All of the mentioned
Correct answer is option 'A'. Can you explain this answer?
Seepage pressure is important for which of the following purpose?
a)
Stability analysis
b)
Structral arrangement
c)
Total head
d)
All of the mentioned
|
|
Gauri Roy answered |
The seepage structure is vital importance in the stability analysis of earth structures subjected to the action of seepage.
What is the line within a dam section, below which there are positive hydrostatic pressures?- a)Phreatic and Seepage line
- b)Equipotential line
- c)None of the mentioned
- d)All of the mentioned
Correct answer is option 'A'. Can you explain this answer?
What is the line within a dam section, below which there are positive hydrostatic pressures?
a)
Phreatic and Seepage line
b)
Equipotential line
c)
None of the mentioned
d)
All of the mentioned
|
|
Anagha Mehta answered |
the phreatic line or seepage line is the line within a dam section below which there are hydrostatic pressures in the dam .the hydrostatic pressure below on the phreatic line itself is atmospheric.
The constant of proportionality between seepage velocity and hydraulic gradient is called- a)Seepage coefficient
- b)Coefficient of transmissibility
- c)Coefficient of permeability
- d)Coefficient of percolation
Correct answer is option 'D'. Can you explain this answer?
The constant of proportionality between seepage velocity and hydraulic gradient is called
a)
Seepage coefficient
b)
Coefficient of transmissibility
c)
Coefficient of permeability
d)
Coefficient of percolation
|
Rutuja Deshpande answered |
Answer:
The constant of proportionality between seepage velocity and hydraulic gradient is called the coefficient of percolation.
Explanation:
Seepage velocity is the velocity at which water flows through a porous medium, such as soil or rock. It is influenced by the hydraulic gradient, which is the change in hydraulic head per unit distance. The hydraulic head is the potential energy per unit weight of water at a specific point in a flow system.
The coefficient of percolation, also known as the coefficient of seepage or coefficient of permeability, is a measure of the ease with which water can flow through a porous medium. It represents the rate at which water can percolate through the medium under a unit hydraulic gradient.
Key Points:
- The coefficient of percolation is denoted by the symbol "k" and has units of length per unit time, such as meters per second or centimeters per day.
- It is a fundamental property of the porous medium and is influenced by factors such as the size and shape of the pores, the connectivity of the pore network, and the viscosity of the fluid.
- The coefficient of percolation can vary widely depending on the characteristics of the porous medium. For example, highly permeable materials, such as gravel or sand, may have high coefficients of percolation, while less permeable materials, such as clay or silt, may have lower coefficients.
- The coefficient of percolation is an important parameter in groundwater flow calculations and is used in various engineering applications, such as the design of drainage systems, the analysis of seepage through dams or embankments, and the evaluation of the potential for contaminant transport through the subsurface.
- The coefficient of percolation can be determined experimentally through laboratory tests, such as constant-head or falling-head permeability tests, or it can be estimated using empirical correlations or derived from field measurements.
In conclusion, the coefficient of percolation is the constant of proportionality between seepage velocity and hydraulic gradient and represents the ease with which water can flow through a porous medium. It is an important parameter in groundwater flow calculations and is influenced by the characteristics of the porous medium.
The constant of proportionality between seepage velocity and hydraulic gradient is called the coefficient of percolation.
Explanation:
Seepage velocity is the velocity at which water flows through a porous medium, such as soil or rock. It is influenced by the hydraulic gradient, which is the change in hydraulic head per unit distance. The hydraulic head is the potential energy per unit weight of water at a specific point in a flow system.
The coefficient of percolation, also known as the coefficient of seepage or coefficient of permeability, is a measure of the ease with which water can flow through a porous medium. It represents the rate at which water can percolate through the medium under a unit hydraulic gradient.
Key Points:
- The coefficient of percolation is denoted by the symbol "k" and has units of length per unit time, such as meters per second or centimeters per day.
- It is a fundamental property of the porous medium and is influenced by factors such as the size and shape of the pores, the connectivity of the pore network, and the viscosity of the fluid.
- The coefficient of percolation can vary widely depending on the characteristics of the porous medium. For example, highly permeable materials, such as gravel or sand, may have high coefficients of percolation, while less permeable materials, such as clay or silt, may have lower coefficients.
- The coefficient of percolation is an important parameter in groundwater flow calculations and is used in various engineering applications, such as the design of drainage systems, the analysis of seepage through dams or embankments, and the evaluation of the potential for contaminant transport through the subsurface.
- The coefficient of percolation can be determined experimentally through laboratory tests, such as constant-head or falling-head permeability tests, or it can be estimated using empirical correlations or derived from field measurements.
In conclusion, the coefficient of percolation is the constant of proportionality between seepage velocity and hydraulic gradient and represents the ease with which water can flow through a porous medium. It is an important parameter in groundwater flow calculations and is influenced by the characteristics of the porous medium.
Khosla’s theory can be used for calculating which of the following?- a)uplift pressure and exit gradient
- b)seepage pressure
- c)None of the mentioned
- d)All of the mentioned
Correct answer is option 'A'. Can you explain this answer?
Khosla’s theory can be used for calculating which of the following?
a)
uplift pressure and exit gradient
b)
seepage pressure
c)
None of the mentioned
d)
All of the mentioned
|
|
Subhankar Khanna answered |
khosla’s theory has an account of flow pattern below the impermeable base of hydraulic structures, hence it can be used to calculate the uplift pressure and the gradient at the exit, called the exit gradient.
A soil mass has kx = 8*10-7cm/s and ky = 4*10-7cm/s. The effective permeability of the soil is ______- a)4.6*10-7cm/s
- b)6.6*10-7cm/s
- c)5.6*10-7cm/s
- d)7.6*10-7cm/s
Correct answer is option 'C'. Can you explain this answer?
A soil mass has kx = 8*10-7cm/s and ky = 4*10-7cm/s. The effective permeability of the soil is ______
a)
4.6*10-7cm/s
b)
6.6*10-7cm/s
c)
5.6*10-7cm/s
d)
7.6*10-7cm/s
|
|
Sanya Agarwal answered |
Given,
kx = 8*10-7cm/s
ky = 4*10-7cm/s
k’ = √(kxky)
k’ = √(8*10-7 *4*10-7)
k’ = 5.6*10-7cm/s.
kx = 8*10-7cm/s
ky = 4*10-7cm/s
k’ = √(kxky)
k’ = √(8*10-7 *4*10-7)
k’ = 5.6*10-7cm/s.
The quantity of water, flowing through a saturated soil mass can be estimated by which of the following theory?- a)Flow of fluids through porous medium
- b)Theoretical analysis of Laplace
- c)Flow of water through saturated soil mass
- d)None of the mentioned
Correct answer is option 'A'. Can you explain this answer?
The quantity of water, flowing through a saturated soil mass can be estimated by which of the following theory?
a)
Flow of fluids through porous medium
b)
Theoretical analysis of Laplace
c)
Flow of water through saturated soil mass
d)
None of the mentioned
|
|
Aarav Chauhan answered |
The quantity of water flowing through a saturated soil mass, as well as the distribution of water pressure can be estimated by the theory of fluids through porous medium.
Kozney’s top flow lines is called as____________- a)Basic and Base parabola
- b)Simple parabola
- c)None of the mentioned
- d)All of the mentioned
Correct answer is option 'A'. Can you explain this answer?
Kozney’s top flow lines is called as____________
a)
Basic and Base parabola
b)
Simple parabola
c)
None of the mentioned
d)
All of the mentioned
|
|
Niharika Yadav answered |
kozney’s solution for flow of water consists of a family of confocal parabola s representing the flow lines. Hence kozney’s top flow line is called the basic or base parabola.
Which one of the following soil types is most likely to be subjected to liquefaction under seismic forces?- a)Soft saturated clays
- b)Loose saturated sands
- c)Murum
- d)Fractured rocky strata
Correct answer is option 'B'. Can you explain this answer?
Which one of the following soil types is most likely to be subjected to liquefaction under seismic forces?
a)
Soft saturated clays
b)
Loose saturated sands
c)
Murum
d)
Fractured rocky strata
|
Jhanvi Choudhary answered |
Liquefaction is a phenomenon where soil loses its strength and stiffness due to the shaking caused by seismic forces. During an earthquake, the ground shakes rapidly and causes the soil particles to lose their interlocking strength. As a result, the soil behaves like a liquid, and the buildings and other structures built on it can sink or tilt.
The soil type that is most likely to be subjected to liquefaction under seismic forces is loose saturated sands. This is because:
1. Porosity: Loose sands have a higher porosity than other soil types, which means they have more void spaces between the grains. This makes them more susceptible to liquefaction because there is more space for the water to flow through and destabilize the soil.
2. Density: Loose sands are less dense than other soil types, which means they are more easily compressed. This makes them more likely to lose their strength and stiffness during an earthquake.
3. Saturation: When soils are saturated with water, the water pressure increases and the soil particles become less interlocked. This makes the soil more susceptible to liquefaction. Loose sands are more likely to be saturated than other soil types because they have a higher porosity.
4. Shape: The shape of the sand particles can also contribute to liquefaction. Angular particles can interlock better than rounded particles, which makes the soil more resistant to liquefaction. Loose sands typically have rounded particles, which makes them more susceptible to liquefaction.
In summary, loose saturated sands are the most likely soil type to be subjected to liquefaction under seismic forces due to their high porosity, low density, high saturation, and rounded particle shape. It is important to consider the soil type and its susceptibility to liquefaction when designing structures in earthquake-prone areas.
The soil type that is most likely to be subjected to liquefaction under seismic forces is loose saturated sands. This is because:
1. Porosity: Loose sands have a higher porosity than other soil types, which means they have more void spaces between the grains. This makes them more susceptible to liquefaction because there is more space for the water to flow through and destabilize the soil.
2. Density: Loose sands are less dense than other soil types, which means they are more easily compressed. This makes them more likely to lose their strength and stiffness during an earthquake.
3. Saturation: When soils are saturated with water, the water pressure increases and the soil particles become less interlocked. This makes the soil more susceptible to liquefaction. Loose sands are more likely to be saturated than other soil types because they have a higher porosity.
4. Shape: The shape of the sand particles can also contribute to liquefaction. Angular particles can interlock better than rounded particles, which makes the soil more resistant to liquefaction. Loose sands typically have rounded particles, which makes them more susceptible to liquefaction.
In summary, loose saturated sands are the most likely soil type to be subjected to liquefaction under seismic forces due to their high porosity, low density, high saturation, and rounded particle shape. It is important to consider the soil type and its susceptibility to liquefaction when designing structures in earthquake-prone areas.
In an earthen dam the phreatic line is- a)straight line
- b)circular line
- c)parabolic line
- d)zigzag line
Correct answer is option 'C'. Can you explain this answer?
In an earthen dam the phreatic line is
a)
straight line
b)
circular line
c)
parabolic line
d)
zigzag line
|
Rutuja Pillai answered |
The correct answer is option 'C' - the phreatic line in an earthen dam is a parabolic line.
The phreatic line in an earthen dam refers to the boundary between the saturated and unsaturated zones within the dam. It represents the water table or the level at which water is present within the dam.
Now, let's understand why the phreatic line takes the shape of a parabolic line in an earthen dam.
1. Nature of Water Flow:
Water flows through the dam in a seepage pattern. Due to the permeability of the soil, water moves from the upstream side to the downstream side of the dam. The seepage flow follows the path of least resistance, which is along the slope of the dam.
2. Slope of the Dam:
The slope of the dam plays a crucial role in determining the shape of the phreatic line. Earthen dams are typically constructed with a downstream slope to ensure stability. The slope can vary depending on the design and the characteristics of the soil used in the construction.
3. Flow Paths:
As water seeps through the dam, it follows different flow paths depending on the permeability of the soil layers. The flow paths can be broadly classified into two types:
- Vertical Flow: Water moves vertically through the dam along the direction of gravity. This vertical flow occurs primarily in the upstream side of the dam.
- Horizontal Flow: Water moves horizontally along the slope of the dam. This horizontal flow occurs in the downstream side of the dam.
4. Combination of Flow Paths:
The combination of vertical and horizontal flow paths results in the formation of the phreatic line. The vertical flow path creates a curved shape of the phreatic line, while the horizontal flow path causes the line to follow the slope of the dam.
5. Parabolic Shape:
Due to the combined effect of the vertical and horizontal flow paths, the phreatic line takes the shape of a parabolic curve. The parabolic shape represents the equilibrium between the vertical and horizontal flow components.
The parabolic shape of the phreatic line in an earthen dam is important for dam design and analysis. It helps engineers understand the seepage patterns and potential areas of concern, such as excessive uplift pressure or erosion along the downstream slope.
In conclusion, the phreatic line in an earthen dam is a parabolic line due to the combined effect of vertical and horizontal water flow paths within the dam.
The phreatic line in an earthen dam refers to the boundary between the saturated and unsaturated zones within the dam. It represents the water table or the level at which water is present within the dam.
Now, let's understand why the phreatic line takes the shape of a parabolic line in an earthen dam.
1. Nature of Water Flow:
Water flows through the dam in a seepage pattern. Due to the permeability of the soil, water moves from the upstream side to the downstream side of the dam. The seepage flow follows the path of least resistance, which is along the slope of the dam.
2. Slope of the Dam:
The slope of the dam plays a crucial role in determining the shape of the phreatic line. Earthen dams are typically constructed with a downstream slope to ensure stability. The slope can vary depending on the design and the characteristics of the soil used in the construction.
3. Flow Paths:
As water seeps through the dam, it follows different flow paths depending on the permeability of the soil layers. The flow paths can be broadly classified into two types:
- Vertical Flow: Water moves vertically through the dam along the direction of gravity. This vertical flow occurs primarily in the upstream side of the dam.
- Horizontal Flow: Water moves horizontally along the slope of the dam. This horizontal flow occurs in the downstream side of the dam.
4. Combination of Flow Paths:
The combination of vertical and horizontal flow paths results in the formation of the phreatic line. The vertical flow path creates a curved shape of the phreatic line, while the horizontal flow path causes the line to follow the slope of the dam.
5. Parabolic Shape:
Due to the combined effect of the vertical and horizontal flow paths, the phreatic line takes the shape of a parabolic curve. The parabolic shape represents the equilibrium between the vertical and horizontal flow components.
The parabolic shape of the phreatic line in an earthen dam is important for dam design and analysis. It helps engineers understand the seepage patterns and potential areas of concern, such as excessive uplift pressure or erosion along the downstream slope.
In conclusion, the phreatic line in an earthen dam is a parabolic line due to the combined effect of vertical and horizontal water flow paths within the dam.
In the zone of soil through which water seeps , there will be____________change in the degree of saturation.- a)More
- b)Less
- c)All of the mentioned
- d)None of the mentioned
Correct answer is option 'D'. Can you explain this answer?
In the zone of soil through which water seeps , there will be____________change in the degree of saturation.
a)
More
b)
Less
c)
All of the mentioned
d)
None of the mentioned
|
|
Anuj Chakraborty answered |
There is no change in the degree of saturation in the zone of soil through which water seeps.
The quantity of water which flows out from any element of volume is_________than quantity which flows out.- a)Greater
- b)smaller
- c)Equal
- d)All of the mentioned
Correct answer is option 'C'. Can you explain this answer?
The quantity of water which flows out from any element of volume is_________than quantity which flows out.
a)
Greater
b)
smaller
c)
Equal
d)
All of the mentioned
|
|
Aarav Chauhan answered |
According to the theoretical analysis of flow of fluids, the quantity of water flowing into any element of volume is equal to the quantity which flows out in the same length of time.
if the permeability of soil does not depend on its mineral content but depends on orientation of particles then the void space is known as- a)Micro-pore
- b)Pore
- c)Capillary
- d)Floe
Correct answer is option 'A'. Can you explain this answer?
if the permeability of soil does not depend on its mineral content but depends on orientation of particles then the void space is known as
a)
Micro-pore
b)
Pore
c)
Capillary
d)
Floe
|
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Shounak Saini answered |
Micropores, often found between and within soil aggregates, are so small that surface tension holds water in place. It does not depend on mineral content rather depends on orientation of the particles. Instead of draining away, water moves through micropores only when suction is created by thirsty roots.
The failure of Naror weir in India was due to__________- a)Excessive water pressure
- b)Undermining
- c)Hydraulic structure
- d)All of the mentioned
Correct answer is option 'A'. Can you explain this answer?
The failure of Naror weir in India was due to__________
a)
Excessive water pressure
b)
Undermining
c)
Hydraulic structure
d)
All of the mentioned
|
|
Anagha Mehta answered |
According to Leliavsky (1965), failure of Norora weir in India was due to excessive water pressure (uplift pressure) causing the floor to be blown upwards.
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