Hydraulics and Principles of Geotechnical Engineering

These flashcards cover key concepts, definitions, and principles related to hydraulics and geotechnical engineering as extracted from the lecture notes.

What is the ratio of volume of voids to volume of soil called?

Porosity.

What is the ratio of volume of voids to volume of soil solids?

Void Ratio.

What is the ratio of volume of water to volume of soil?

Degree of Saturation.

Which is true for porosity?

0 ≤ n ≤ 100.

Which is true for void ratio?

0 ≤ e.

Which is true for degree of saturation?

0 ≤ S ≤ 100.

In the unit phase diagram for a soil mass, what is the total volume taken as?

Unity.

What does 'loam' refer to in soils?

A mixture of sand, silt, and clay size particles in approximately equal proportions.

Which principle is involved in the relationship between submerged unit weight and saturated unit weight of a soil?

Archimedes' Principle.

What is soil as defined in civil engineering?

The unaggregated and uncemented deposits of minerals and organic particles covering the earth’s crust.

What happens when the water table rises above the ground surface?

Increase in pore water pressure but decrease in total stress.

How is shear strength of a soil related to the angle of internal friction?

It is directly proportional to the angle of internal friction.

What effect does effective stress on soil have on voids ratio and permeability?

Decreases voids ratio and increases permeability.

What is the coefficient of compressibility of soil a ratio of?

Stress to strain.

What is the unconfined compression strength range for stiff cohesive soil?

100 to 200 kPa.

What is the unconfined compression strength range for soft cohesive soil?

0 to 25 kPa.

What is the unconfined compression strength range for very soft cohesive soil?

0 to 25 kPa.

When shearing stress is zero on two planes, what is the angle between them?

90°.

Rapid compression of soil occurs if voids are filled with?

Water.

What type of soil is cohesionless?

Sand.

What is the name of the test done in a triaxial compression test when drainage is allowed only during the first stage?

Consolidated undrained test.

Where is the metacenter for stable equilibrium located?

Above the center of gravity.

What happens when the metacenter of a floating body is lower than the center of gravity?

The body will be in unstable equilibrium.

What is the distance between the center of gravity and the metacenter called?

Metacentric height.

What is the weight per unit volume of a liquid at standard temperature and pressure called?

Specific weight.

What is referred to in hydraulics as the pressure surge caused when a fluid's motion is suddenly stopped?

Water hammer.

What is a sudden transition from swift flow to tranquil flow called?

Hydraulic jump.

What measures a fluid’s resistance to shear stress?

Viscosity.

What is the vena contracta of a circular orifice approximately?

1/2 diameter downstream from the orifice plate.

What occurs when a ship’s metacenter and center of gravity coincide?

The vessel is said to be in equilibrium.

What is the force within the surface layer of a liquid that causes it to behave like an elastic sheet?

Surface tension.

In a triaxial test, what increases shear stress on what plane?

The deviator stress increases shear stress on all planes.

Which test is not performed in a laboratory setup?

Vane shear test.

What happens to shear strength when normal stress increases?

Increases with an increase in normal stress.

What do minor losses through valves and fittings model as?

Proportional to total head.

In a trapezoidal channel, what is the best hydraulic cross section ratio of side edges?

b.

What is the flow called when particles of a liquid continually cross each other forming a network?

Turbulent flow.

What type of flow has a constant flow rate over time?

Steady flow.

What is uninterrupted flow in a fluid near a solid boundary called?

Laminar flow.

What type of flow ensures the discharge remains constant at every section of a stream?

Continuous flow.

What is the specific energy at minimum for critical flow?

Critical flow.

What describes a fluid with density constant from one point to another?

Incompressible flow.

What describes fluid particles rotating about their own axis along streamlines?

Rotational flow.

What statement is incorrect concerning specific energy?

Velocity of flow is critical at maximum specific energy.

How can water hammer pressure be reduced?

Using a more elastic pipe.

What will happen to water level when a partially filled water tank is moved with constant horizontal acceleration?

Fall on the rear side of the tank.

As depth of immersion increases, where does the center of pressure move?

Moves apart from the center of gravity.

Under what condition does water flow in an open channel?

Force of gravity.

Which principle in fluid mechanics states that pressure is transmitted undiminished through a liquid?

Pascal's principle.

What principle states that the total energy contained in a stream without friction remains constant?

Bernoulli's principle.

What happens to the volume of gas at constant temperature as pressure increases?

It varies inversely.

What is the porosity and void ratio if volume of voids equals volume of solids?

0 and 1.

What is the term for the process where water-saturated soil temporarily loses strength?

Liquefaction.

Which soil contains the finest grain particles?

Clay.

What does it mean if the plasticity index of a soil is zero?

Soil is sand.

What causes volume change in saturated soils?

Expulsion of pore water from loading.

What is neutral stress in a soil mass?

Stress taken up by the pore water.

What causes negative skin friction on piles?

Relative settlement of the soil.

What happens to bearing capacity if ground water rises due to flooding?

Decreases.

Which foundation condition does not affect bearing capacity?

Unit weight of the soil.

What results from a decrease in water content in soil?

Reduction of volume of soil.

What is the water content when the soil loses weight but not volume?

Shrinkage limit.

What is reported if the plastic limit is greater than the liquid limit?

Negative.

What equation is based on the conservation of mass?

Continuity equation.

What occurs when a valve suddenly closes on a liquid?

Water hammer.

What accounts for major losses in pipes due to fluid properties?

Viscosity.

When water in an open vessel is moved up an inclined plane what happens?

Makes an angle in direction of inclination.

What is the horizontal to vertical side slope for a Cipolletti weir?

1:2.

What is equal to the horizontal component of force on a curved surface?

Force on a vertical projection of the curved surface.

What is the condition for the most economical trapezoidal channel?

Half of the top width must equal one of the sloping sides.

What is the SPT 'N' value for dense cohesionless soil?

30 to 50.

What is the SPT 'N' value for loose cohesionless soil?

10 to 30.

What is the SPT 'N' value for very loose cohesionless soil?

0 to 4.

What is the grain size for soil greater than 4.75 mm but less than 75 mm?

Gravel.

What is the grain size for soil greater than 75 mm?

Boulders.

On which filament does maximum shear stress occur?

On the filament making a 45° angle with the horizontal plane.

What practice assesses particle size distribution of granular material?

Sieve Analysis.

What is the permeability behavior of natural deposits parallel and perpendicular to stratification?

Is always greater parallel to stratification.

Which of the following transports and re-deposits soils?

All of the above.

What do residual soils originate from?

Weathering of parent rock.

What are textural classifications based on?

Grain size.

What is the minimum number of observation wells for determining permeability by a pumping test?

Two.

What is consolidation a function of?

The effective stress.

What does allowable bearing pressure depend on?

Both allowable settlement and ultimate bearing capacity.

What is the over consolidation ratio (OCR) of over consolidated soil?

Greater than 1.

What is the OCR of normally consolidated soil?

Equal to 1.

Which statement regarding failure planes is correct?

Failure plane carries maximum shear stress.

What does it mean at the liquid limit for the shear strength of soil?

No shearing strength.

What theorem relates speed of fluid flowing out of an orifice to height of fluid?

Torricelli's theorem.

What is gauge pressure?

Absolute pressure - atmospheric pressure.

In flow, what type of energy may liquid particles possess?

All of the above.

What is the depth in the most economical rectangular section of a channel?

One-fourth of the width.

What index identifies swelling potential of clay soils?

Plasticity Index.

What property allows water to percolate through soil?

Permeability.

Which method best determines permeability of coarse-grained soils?

Constant head method.

What are Terzaghi's bearing capacity factors functions of?

Both cohesion and angle of internal friction.

What describes the coefficient of earth pressure at rest?

Greater than active earth pressure but less than passive earth pressure.

What affects atmospheric pressure?

All of the above.

What describes the rise of liquid along the walls of a revolving cylinder?

Greater than the depression at the axis of rotation.

What defines the specific weight of water at normal pressure?

1000 kg/m³.