Chapters 2 to 16 Covered
SOLUTIONS
,Exercise 2.1 (a) What are the three layers that make up the earth’s internal structure?
(b) What is the composition of each of the layers?
Solution 2.1
a) The core, the mantle and the crust
b) Studies from elastic waves generated by earthquakes showed that the earth has a core of
heavy metals mostly iron. The mantle consists of two parts; upper mantle which is solid
rock and lower mantle which is molten rock. Above the upper mantle is the crust. The
materials that compose the earth’s crust are sediments and rock.
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,Exercise 2.2 (a) Describe the differences among the three key groups of rocks.
(b) Explain why sedimentary rocks are of particular importance to geotechnical
engineers.
(c) Are rock masses homogeneous and continuous? Explain.
Solution 2.2
a) There are three main groups of rocks;
i. Igneous rocks. They are formed from magma emitted from volcanoes
that have cooled and solidified.
ii. Sedimentary rocks. They are formed from sediments animals and plant
materials that are deposited in the water or on land on the earth’s
surface and then subjected to pressures and heat.
iii. Metamorphic rocks. They are formed deep within the earth’s crust
from the transformation of igneous, sedimentary, and even existing
metamorphic rocks into denser rocks.
b) They cover 75% of the earth’s surface area with an average thickness of 0.8
km.
c) Rock masses are seldom homogeneous and continuous.
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, Exercise 2.3 (a) How are soils formed?
(b) What are the agents responsible for weathering of rocks?
Solution 2.3
a) Soils are formed from the physical and chemical weathering of rocks.
a. Physical weathering involves reduction of size without any change in the original
composition of the parent rock.
b. Chemical weathering causes both reductions in size and chemical alteration of the
original parent rock
b) Main agents responsible for physical weathering are; exfoliation, unloading, erosion,
freezing and thawing. Main agents responsible for chemical weathering are; hydration,
carbonation, and oxidation
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SOLUTIONS
,Exercise 2.1 (a) What are the three layers that make up the earth’s internal structure?
(b) What is the composition of each of the layers?
Solution 2.1
a) The core, the mantle and the crust
b) Studies from elastic waves generated by earthquakes showed that the earth has a core of
heavy metals mostly iron. The mantle consists of two parts; upper mantle which is solid
rock and lower mantle which is molten rock. Above the upper mantle is the crust. The
materials that compose the earth’s crust are sediments and rock.
@Seismicisolation
@Seismicisolation
,Exercise 2.2 (a) Describe the differences among the three key groups of rocks.
(b) Explain why sedimentary rocks are of particular importance to geotechnical
engineers.
(c) Are rock masses homogeneous and continuous? Explain.
Solution 2.2
a) There are three main groups of rocks;
i. Igneous rocks. They are formed from magma emitted from volcanoes
that have cooled and solidified.
ii. Sedimentary rocks. They are formed from sediments animals and plant
materials that are deposited in the water or on land on the earth’s
surface and then subjected to pressures and heat.
iii. Metamorphic rocks. They are formed deep within the earth’s crust
from the transformation of igneous, sedimentary, and even existing
metamorphic rocks into denser rocks.
b) They cover 75% of the earth’s surface area with an average thickness of 0.8
km.
c) Rock masses are seldom homogeneous and continuous.
@Seismicisolation
@Seismicisolation
, Exercise 2.3 (a) How are soils formed?
(b) What are the agents responsible for weathering of rocks?
Solution 2.3
a) Soils are formed from the physical and chemical weathering of rocks.
a. Physical weathering involves reduction of size without any change in the original
composition of the parent rock.
b. Chemical weathering causes both reductions in size and chemical alteration of the
original parent rock
b) Main agents responsible for physical weathering are; exfoliation, unloading, erosion,
freezing and thawing. Main agents responsible for chemical weathering are; hydration,
carbonation, and oxidation
@Seismicisolation
@Seismicisolation
