Review

Question 1

use to represent the soil mass

Answer 1

Phase diagram

Question 2

Classification is based on the following physical properties

Answer 2

Grain Size Distribution
Liquid Limit
Plasticity Index

Question 3

gives some idea about the general behavior of soil.

Answer 3

Classification

Question 4

Two commonly used systems engineering based soil classification

Answer 4

USCS (Unified Soil Classification System)
AASHTO (American Association of State Highway and Transportation Officials System)

Question 5

_______ generally separates the more claylike materials from silty materials, and the organic from inorganics.

Answer 5

A-line

Question 6

______ indicates the upper bound for general soils

Answer 6

U-line

Question 7

If the measured limits of soil are on the left of u-line, they should be _______

Answer 7

rechecked

Question 8

The water content, in percentage, required to close a distance of 0.5 in (12.7mm) along the bottom of the groove after 25 blows is defined as the _________.

Answer 8

liquid limit

Question 9

This method is developed by the transport and road research laboratory

Answer 9

Fall cone method

Question 10

is defined as the water content at which a soil thread with 3.2 mm diameter just crumbles

Answer 10

Plastic Limit (ASTM D4318)

Question 11

There are two engineering equations that govern fluid flow through soils.

Answer 11

Bernoulli’s Equation
Darcy’s Law

Question 12

In a ________ medium velocity head is neglected because seepage velocity is small

Answer 12

Porous soil

Question 13

summation of pressure head and elevation head

Answer 13

Total head

Question 14

Height of the water in the piezometer down to the point of insterest

Answer 14

Pressure Head

Question 15

Distance from the defined datum to the point of interest

Answer 15

Elevation head

Question 16

Energy loss in the flow

Answer 16

Head loss

Question 17

In 1856, ____ published a simple equation for the discharge velocity of water through saturated soils

Answer 17

Darcy

Question 18

____, ____ between soil grains allow water to flow through them.

Answer 18

Void space, or pores

Question 19

is a line along which a water particle will travel from upstream to the downstream side in the permeable soil medium

Answer 19

Flow Line

Question 20

Is a line along which the potential head at all points is equal

Answer 20

Equipotential line

Question 21

A combination of a number of flow lines and equipotential lines is called ______

Answer 21

Flow net

Question 22

__________ along a given cross section of the
soil profile is key to analyzing the compressibility of
soils, bearing capacity of foundations, stability of
embankments and lateral earth pressure on earth
retaining structures.

Answer 22

Nature of stresses

Question 23

______ is a multi-phase system

Answer 23

Soil

Question 24

The ___________ supports those stresses at the point to point contacts of the
individual soil grains

Answer 24

soil mass

Question 25

Stress due to soil weight and water only

Answer 25

Geostatic Stresses

Question 26

Stress due to construction of fills and foundations - Excess stress stresses

Answer 26

Induced Stresses

Question 27

________ geostatic stresses increase with depth

Answer 27

Vertical

Question 28

When a load is applied to soil, it is carried by the_______ in the pores as well as the solid grains.

Answer 28

water

Question 29

The increase in pressure within the pore water causes _________

Answer 29

drainage

Question 30

The rate of drainage depends on the ___________ of the soil.

Answer 30

permeability

Question 31

The strength and compressibility of the soil depend on the stresses within the solid granular fabric. These are called _________

Answer 31

effective stresses.

Question 32

The sum of the vertical components of the forces developed at the points of contact of the solid particles per unit cross-sectional area of the soil mass is called the __________

Answer 32

effective stress.

Question 33

The _________ principle is probably the most important concept in geotechnical engineering.

Answer 33

effective stress

Question 34

The __________and _____________ of soil depends to a great extent on the effective stress.

Answer 34

compressibility , shearing resistance

Question 35

As water flows through soil it exerts a frictional drag on the soil particles resulting in head losses. The frictional drag is called ________ in soil mechanics.

Answer 35

seepage force

Question 36

If the seepage direction is ______, then the resultant seepage stresses are in the same direction as the gravitational effective stresses.

Answer 36

downwards

Question 37

Zone between the land surface and water table Pore contains water and air Also called as vadose zone or the zone of aeration

Answer 37

Unsaturated zone

Question 38

pores are completely filled with water Contains water at greater than atmospheric pressure Also called phreatic zone

Answer 38

Saturated zone

Question 39

Surface where the pore water pressure is atmospheric Divide between saturated and unsaturated zone

Answer 39

Water table

Question 40

Zone immediately above the water table that gets saturated by capillary forces

Answer 40

Zone Capillary Rise/Fringe

Question 41

. Microscopic film of water surrounding soil particles Strong molecular attraction; water cannot be removed by natural forces Adhesive forces (>31 bars and up to 10,000 bars!)

Answer 41

Hygroscopic water

Question 42

Water held by cohesive forces between films of hygroscopic water Can be removed by air drying or plant absorption Plants extract capillary water until the soil capillary force is equal to the extractive force - Wilting point: soil capillary force > plant extractive force

Answer 42

Capillary water

Question 43

Water that moves through the soil by the force of gravity

Answer 43

Gravity water

Question 44

Amount of water held in the soil after excess water has drained is called the field capacity of the soil.

Answer 44

Field capacity

Question 45

Below the water table, pore pressures are _____. In dry soil, the pore pressure is ____. Above the water table, when the soil is saturated, pore pressure will be ________.

Answer 45

positive, zero, negative

Question 46

The height above the water table to which the soil is saturated is called the __________

Answer 46

capillary rise

Question 47

In soils voids exist between particles and the voids may be filled with a liquid, usually water, or gas, usually air. As a result, soils are often referred to as a ______ material or system (solid, liquid and gas).

Answer 47

three-phase

Question 48

Compression of soil is due to a number of mechanisms:

Answer 48

Deformation Relocation Expulsion

Question 48

Most common type of shear failure; occurs in strong soils and rocks

Answer 48

General Shear Failure

Question 48

In the case the applied load caused shearing stresses to develop within the soil mass which are greater than the shear strength of the material, then the soil fails by sliding downward and laterally, and the structure settle and may tip of vertical alignment. This is what we referred to as __________

Answer 48

BEARING CAPACITY.

Question 49

Intermediate between general and punching shear failure

Answer 49

Local Shear Failure

Question 50

Occurs in very loose sands weak clays

Answer 50

Punching Shear Failure

Question 51

Takes place during or immediately after the construction of the structure. It is also known as the distortion settlement as it is due to distortions within foundation soil.

Answer 51

Immediate settlement (Si)

Question 52

Occurs due to gradual expulsion of water from the voids at the soil. It is determined using Terzaghi's theory of consolidation.

Answer 52

.Primary Consolidation settlement (Sc):

Question 53

Occurs after completion of the primary consolidation. The secondary consolidation is non-significant for inorganic soils.

Answer 53

.Secondary consolidation settlement (Ss)

Question 54

For shallow foundation subjected to a net force per unit area equal to Δσ and if the foundation is __________

Answer 54

perfectly flexible

Question 55

Whose present effective overburden pressure is the maximum pressure that the soil was subjected to in the past condition. The current effective stress σ' is equal o'p

Answer 55

Normally consolidated soil

Question 56

Maximum past effective pressure

Answer 56

Preconsolidation pressure

Question 57

Whose present effective overburden pressure is less than that which the soil experienced in the past.

Answer 57

Overconsolidated soil:

Question 58

A soil is said to over consolidated if it had been subjected in the ______ to a pressure in excess of the present pressure. The soil in the range CD (loading-unloading curve) when it recompressed represent _______________.

Answer 58

past, overconsolidated condition

Question 59

It is the defined as the ratio of pre-consolidation pressure to the present vertical effective stress

Answer 59

Overconsolidation Ratio (OCR)

Question 60

- Soils having higher ______ are less compressible -- They show elastic behavior to certain extent

Answer 60

OCR (Over Consolidated Ratio)

Question 61

After complete dissipation of excess pore water pressure) some settlement is observed because of the plastic adjustment of soil fabrics. This stage of consolidation is called ___________

Answer 61

Secondary consolidation.

Question 62

There are a few methods available, but most engineers still use the ____________ graphical procedure for finding J'

Answer 62

Casagrande

Question 63

________________settlement is more important than primary consolidation in organic and highly compressible inorganic soils.

Answer 63

Secondary consolidation

Question 64

In ____________________---, the secondary compression index is very small and of less practical significance.

Answer 64

overconsolidated inorganic clays,