Name of the College : Kings College of Engineering
University : Anna University Chennai
Department : Civil Engineering
Subject Code/Name : CE 2251 Soil Mechanics
Year : II
Semester : IV
Degree : B.E
Website : kings.ac.in
Document Type : Question Bank
Download : https://www.pdfquestion.in/uploads/ki…0MECHANICS.pdf
Kings Soil Mechanics Question Bank
Unit – I
Introduction :
1 .Define soil? :
Uncemented or weakly cemented accumulation of mineral and organic particles and sediments found above the bedrock, or any unconsolidated material consisting of discrete solid particles with fluid or gas in the voids.
Related : Kings College of Engineering CE1353 Irrigation Engineering B.E Question Bank : www.pdfquestion.in/1540.html
2. Define Soil Mechanics ? :
Soil mechanics is defined as the study of action of forces on soil and the study of flow of water through soil.
3. List the Main Types of Soils ? :
The types of soil are
Granular or cohesioless : gravel, sand, (silt)
Cohesive : (silt), clay
Organic : marsh soil, peat, coal, tar sand
Man-Made : mine tailings, landfill waste, ash, and aggregates.
4. Draw the phase diagram ? :
5. Define soil Index ? :
Where,
emax = maximum void ratio corresponding to the loosest state,
emin = minimum void ratio corresponding to the densest state, and
e = void ratio of the sample.
6. Give an empirical correlation between PSD and permeability ? :
An empirical correlation between PSD and permeability has been developed
k = c (D10)2 cm/s
Where 100 < c < 150
Developed by Hazen for uniform, loose, clean sands and gravels.
7. Define degree of saturation ? :
The degree of saturation is defined as the ratio of volume of water to the volume of voids
Sr =Vw/Vv
For fully saturated soil Sr=100,
For perfectly dry soil Sr=0
8. Define Void Ratio ? :
The void ratio of a soil is defined as the ratio of volume of voids to the volume of solids.
e = Vv/Vs
9. Define specific gravity ? :
It is defined as the ratio of the mass of a given volumes of solid gains to the mass of equal volume of water at the same temperature
10. Define Density ? :
The density of a substance is the mass per unit volume of that substance. For water this is denoted by w, and its value is about 1000 kg/m3. Small deviations from this value may occur due to temperature differences or variations in salt content. In soil mechanics these are often of minor importance, and it is often considered accurate enough to assume that w = 1000 kg/m3.
11. Define water content ? :
By definition the water content w is the ratio of the weight (or mass) of the water to the wt of solids, w = Ww/Ws.
Unit – II
Soil Water And Water Flow :
1. What are the factors that affect hydraulic conductivity?
The hydraulic conductivity is influenced by a number of factors
including:
– Effective porosity
– Grain size and grain size distribution
– Shape and orientation of particles
– Degree of saturation
– Clay mineralogy
2. What are assumptions made to derive the equation governing two dimensional steady state seepage? Several assumptions are required to derive the equation governing two dimensional steady state seepage.
• The soil is completely saturated
• There is no change in void ratio of the porous medium
• The hydraulic conductivity is isotropic
• Darcy’s law is valid
• The water is incompressible
3. What are the steps in the construction of a flownet?
Steps in Drawing a Flow Net
Define and clearly mark a datum.
Identify the boundary conditions (EP, FL, LCP).
Draw intermediate equipotentials and flow lines.
draw coarse mesh with a few EPs and FLs
Verify the coarse mesh is correct.
Are the boundary conditions satisfied ?
Are all flow tubes continuous ?
Are EPs z FLs ? only if isotropic medium
Mostly “squares” ?
Add additional EPs and FLs for suitable refinement of the flow net.
Calculate desired quantities of flow and heads.
4. Define Seepage velocity ?
The actual velocity of water flowing through the voids is termed as seepage velocity.
PART – B
1. Explain in detail the laboratory determination of permeability using constant head method.
2. Explain in detail the laboratory determination of permeability using falling head method.
3. Derive the Laplace equation for two-dimensional flow.
4. Explain in detail the properties and applications of flow nets.
5. Explain in detail the procedure for drawing the phreatic line for an earthen dam.
Unit – III
STRESS DISTRIBUTION, COMPRESSIBILITY & SETTLEMENT
1.What is a principal plane?
At every point in a stressed body, there are three planes on which the shear stresses are zero. These planes are known as principal planes.
2. What are the limitations of coulomb’s theory?
The limitations of coloumb theory are
• It neglects the effect of the intermediate principal stress.
• It approximates the curved failure envelope by a straight line which may not give correct results.
3. Give the Coulomb’s shear strength equation ?
The Coulomb’s shear strength equation is given by,
S= c+s tan j
C= cohesion
j = Angle of internal friction
4. What is Unconsolidated- Undrained condition?
In this type of test no drainage is permitted during the consolidation stage. The drainage is also permitted in the shear stage.
5. What is consolidated- undrained condition?
In a consolidated- undrained test, the specimen is allowed to consolidate in the first stage. The drainage is permitted until the consolidation is complete.
PART – B
1. Derive the equation for Terzhaghi’s one-dimensional consolidation.
2. Explain in detail the laboratory determination of co-efficeint of consolidation.
3. Explain the concept of consolidation using Terzaghi’s mechanical model.
4. Explain the principle of Newmark’s Chart in detail.
5. Explain in detail with sketches the applications of Boussinesq theory.