Chapter 1 soil

1. CHAPTER 1
SOIL
Al-Hafzan Abdullah Halim

2. DEFINITION
The simplest classification of geological
deposits falls generally into two major classes
to provide engineers and others with basic
information which is:
“ROCK”- which refers mainly to a hard rigid
and strongly cemented deposit, and
“SOIL”- which refers to the soft, or loose and
cemented deposis

3. IMPORTANCE
For construction purposes
Structure implementation
Foundation choices
Reduce the risk of soil/foundation failure

4. SOIL STRATUM
2 layers
Top soil
Ground soil

5. Top soil
150-300mm from soil surface
Contains vegetation, rubbish & rotten
materials
Not suitable in supporting foundation/structure
Usually the top soil will be cart away before
construction

6. GROUND SOIL
Situated between top soil & rock layer
The thickness of the soil varies depending on
the rock formation
This layer are compacted naturally which
occasionally can support light construction

7. SOIL FORMATION
3 types of formation
Transported soil
Residual soil
Organic soil

8. TRANSPORTED SOIL
E.g. – gravel, sand, silt and clay
Produce by the formation of wind and water
Dust flown by wind

9. RESIDUAL SOIL
E.g. – top soil & laterite
weathering action on rock fragments which
breaks and crushed and becomes smaller
pieces

10. ORGANIC SOIL
E.g. – top soil and peat
Produce by the formation of rotten vegetation
and animals

11. ROCK FORMATION
Divided into 3 major groups:
Igneous rocks
Sedimentary rocks
Metamorphic rocks

12. IGNEOUS ROCK
E.g. – basalt & granite
Formed by solidification of molten materials
which has ascended towards the surface from
the hot lower levels of the earth crust

13. SEDIMENTARY ROCKS
E.g.-sandstone, shale, limestone
Formed by deep fissures and swallow holes
which are cavities formed at some time by the
passage of water through soft rock.

14. METAMORPHIC ROCKS
E.g.-slates, quartzite, marble
These rocks include any sedimentary deposit
or igneous rock which, after consolidation, has
become altered by heat or pressure

15. TYPES OF SOIL
2 types of soil
Non-cohesive soils
Cohesive soils

16. COHESIVE SOILS
•Fine grained particles are closely integrated and stick
together
•Particle size ranges between 0.06mm or less
•The level of cohesiveness depends on the size, shape and
water level
•When its wet, it is soft and when its dry it becomes hard
•Has a high level of moisture content
•Always experiences shrinkage and extension process
•The increasing of water level can caused soil strengths to
differ
•Therefore the depth of the foundation should be constructed
at least 1m from the earth surface

17. High level of water content can caused
difficulty in earth excavation which will flood
the construction site
E.g- clay,silt, peat and laterite

18. NON-COHESIVE SOIL
The soil particles are not sticking to each other
The particle size ranges between 0.06mm-
200mm
Non-cohesive soils has a high value for a
construction site
Water are easy to flow out because of its
hollow particle
E.g- gravel, sands

19. CLASSIFICATION OF SOILS
Soil classification can be done by:
Grain size-divided into several sizes
Coarse grain non-cohesive
Fined grained cohesive
Organic soil
Can be done by sieving and sedimentation technique
-Sieving : for non-cohesive soil such as gravel and
sand
-Sedimentation : for cohesive soil such as clay and silt

20. Moisture content
Moisture content classification for cohesive
soil such as clay and silt
Can be classified by moisture content test or
plastic limit/liquid limit test. Refer to BS
1377:1975

21. GROUND WATER
Usually refer to the ground water level
Water usually come from rain and water penetration into
the earth opening which can penetrates until 12000m
Water content depends on:
Surface slopes/gradients
Vegetation
Weather
Soil opening and penetration
- Ground water content will influence construction works where it
involved the stabilization and strength of the soil.

22. - Usually high level of water content require a much
more complicated foundation system.
-It will also make more difficult when water
penetrates into excavation work and will obstruct
workers and machineries.
-Water proof retaining wall needed in such cases

23. SOIL CHARACTERISTIC IN
RELATION TO CHOICE OF
FOUNDATIONS
Soil have different attribute when load implied
on them. The characteristic are:
Compressibility
Permeability
Plasticity

24. CHOICES OF FOUNDATION
Solid chalk, sands and gravels or sand and gravels with
only small proportions of clay, dense silty sands
Shallow strip or pad footings as appropriate to the load
bearing members of the building
Uniform, firm and stiff clays
-Where vegetation is insignificant
-Where trees and shrubs are growing or to be planted
close to the site
-Where trees are felled to clear the site and construction is
due to start soon afterward
-Bored piles and ground beams, or strip foundations at
least 1m deep
-Bored piles and ground beams
-Reinforced bored piles of sufficient length with the top 3m
sleeved from the surrounding ground and with suspended
floor
Soft clays, soft silty clays Strip footing up to 1m wide if bearing capacity is sufficient,
or raft
Peat Bored piles with temporary steel lining or precast or insitu
piles driven to firm strata below
Mining and other subsidence area Thin reinforced rafts for individuals houses with load
bearing walls and for flexible building