College of Engineering and Architecture
Department of Civil and Environmental Engineering
Fall 2011/ 2012 Semester
MID-TERM EXAM-I
CIVL331 Engineering Geology
Date: October 31, 2011
Time: 12.00 – 12.50 P.M.
Venue: 17B
Faculty: Dr.S.Sreedhar Reddy
Examination Notes
Answer all questions
Maximum Marks: 100
Q1 Select the correct option (30 marks)
1. Which of the following is not a mineral? ( )
A) Olivine B) limestone C) calcite D) quartz
2. The average thickness of the continental crust is about ( )
A) 35-40 km B) 100-200 km C) 1000-2000 km D) 5-10 km
3. In correct order from the center outward, Earth includes which layers? ( )
A) Core, inner mantle, outer mantle, crust B) inner core, outer core, mantle, crust
C) Inner core, crust, mantle, hydrosphere D) core, crust, mantle, hydrosphere
4. According to Plate Tectonics theory, most active volcanoes occur ( )
A) On continents. B) In large tectonic plates.
C) Along plate boundaries. D) Randomly over continents.
5. What are the two most abundant elements in the Earth’s crust? ( )
A) Iron and magnesium B) oxygen and silicon
C) Nitrogen and oxygen D) silicon and calcium
6. What mineral is the hardest known substance in nature? ( )
A) Graphite B) native gold C) diamond D) muscovite
7. Which of the following is NOT a process of physical (mechanical) weathering? ( )
A) Frost wedging B) recrystallization C) thermal expansion D) dissolution
8. Which of the following silicate minerals are most resistant to chemical weathering? ( )
A) Quartz B) olivine C) hornblende D) potassium feldspar
9. The layer that separates the crust from the core is ( )
A) Magma layer B) lithosphere C) mantle D) continent
10. ......................... called father of geology ( )
A) John Butler B) Art Smith C) James Hutton D) Alfred Wegner
11. What caused dust and condensing material to accrete in to plantestimals ( )
A) Heating of gases B) Gravitational attractions and collisions
C) Nuclear fusion D) rotation of the sun
12. The moon is ( )
A) Older than the sun B) older than the earth C) older than most planets D) None of these
13. Which of the following is NOT considered a physical property of minerals? ( )
A) Dissolution B) Streak C) Silicate structure D) luster
14. Select the statement about cleavage which is NOT correct: ( )
A) A plane along which crystals break easily B) a plane that reflects light
C) It is well developed in all minerals
D) There may be more than one cleavage plane in some minerals
15. For a given mineral, the physical property which displays the greatest variation is: ( )
A) Color B) Luster C) Hardness D) streak
Q2 Indicate TRUE or FALSE (25 marks)
1. Because we rarely witness dramatic changes in the earth, we can conclude that earth is not changing very much.( F )
2. The motions of three types of plate boundaries would be described as divergent, convergent and static.( F )
3. The terms crust and lithosphere have same meaning.( T )
4. Mechanical unloading is an example for physical weathering. ( T )
5. Unconfined compressive strength of fresh rock will be lower than highly weathered rock.( F )
6. Mass wasting is mainly due to the force of gravity.( T )
7. Erosion is measured using micro sedimentation meter.( F )
8. Normally draas can be found on dunes.( F )
9. Mohs hardness of topaz is 8. ( T )
10. Two minerals may be the same size, but their weight may be very different.( T )
11. Geomorphology deals with the study of landforms.( T )
12. Always continental crust is thicker than oceanic crust.( T )
13. A soil weathered from a mix of rock types often makes more fertile soil.( T )
14. Sultanate of Oman is located in Arabian plate.( T )
15. Hydrological maps give broad details about rock types.( F )
Q3 Answer the following Questions (45 marks)
Q3-A) Briefly describe the role of engineering geology during planning and construction phase of a civil engineering project in points. (10 marks)
Answer
Planning Stage:
Following geological information is greatly useful in proper planning of a civil engineering project:
(i) Topographic Maps: Such maps give details of relief features and are essential to understand relative merits and demerits of all possible sites for the proposed project.
(ii) Hydrological Maps: These maps give broad details about the distribution and geometry of the surface water channels and also the occurrence and depth contours of ground water below the surface of the earth.
(iii) Geological Maps: Petrologic characters and structural deposition of rock types as developed in the proposed area are depicted in the geological maps.
(c) Construction
1. Knowledge of geology is necessary for selection and proper use of right type of material, quality control (sand, gravel, crushed rocks and soils).
2. Knowledge of geological history is very important for construction in geologically sensitive areas like coastal belts, seismic zones and permafrost regions.
3. Construction of under ground projects like construction of tunnels. The same type of rock may behave totally in a different way under different natural settings. Knowledge of behaviour of rocks under imposed loads and relieved loads.
Q3-B) Name the various physical and chemical processes responsible for weathering of rocks.
(13 marks)
Answer:
Physical processes responsible for weathering:
1. Mechanical Unloading
2. Mechanical loading
3. Thermal loading
4. Wetting and Drying
5. Crystallization
6. Pneumatic loading
Chemical processes responsible for weathering
1. Carbonation
2. Hydrolysis
3. Oxidation
4. Solution
5. Hydration
Q3-C) What is sediment transport? Explain how knowledge of sediment transport helpful in solving in civil engineering problems. (12 marks)
Answer:
Sediment transport is the movement of solid particles (sediment), typically due to a combination of the force of gravity acting on the sediment, and/or the movement of the fluid in which the sediment is entrained.
Sediment transport due to fluid motion occurs in rivers, the oceans, lakes, seas, and other bodies of water, due to currents and tides and on terrestrial surfaces under the influence of wind.
Sediment transport due only to gravity can occur on sloping surfaces in general on hill slopes.
Applications of Sediment Transport
Sediment transport is applied to solve many environmental, geotechnical, and geological problems.
1. Sediment discharge into a reservoir formed by a dam forms a reservoir delta. This delta will fill the basin, and eventually, either the reservoir will need to be dredged or the dam will need to be removed. Knowledge of sediment transport can be used to properly plan to extend the life of a dam.
2. Flow in culverts, over dams, and around bridge piers can cause erosion of the bed. This erosion can damage the environment and expose or unsettle the foundations of the structure. Therefore, good knowledge of the mechanics of sediment transport in a built environment are important for civil and hydraulic engineers.
Q3-D) Define (a) Specific gravity of rock solids (b) Mohs hardness scale (C) Cleavage of quartz, and (d) Loess
(10 marks)
1