Soil Analysis for Building Structures and Materials Assignment

This report presents a detailed analysis of soil properties across three distinct zones, focusing on their suitability for building structures and materials. Zone 1, characterized by sandy soil and swampy conditions, is evaluated for ease of digging, ground stability, retaining wall constructability, and footing selection, including stiffened raft footings and slab footings. Zone 2, with clayey soil and a sloping terrain, assesses similar factors, highlighting the challenges posed by the soil type and the need for retaining walls. Footing options, such as stiffened raft footings and stiffened slabs with deep edge beams, are considered. Zone 3, the steepest of the three, also undergoes analysis of soil properties, emphasizing the importance of leveling the site and the use of retaining walls to manage the risk of landslides and rock falls. The report compares the characteristics of each zone, providing a tabular comparison and references to relevant standards and guidelines. The report emphasizes on the importance of understanding soil properties for safe and effective building design. The report covers different types of footings for different soil types to ensure the stability of the structure.

Student Name
[Pick the date]
Building Structures and Materials
A Brief Analysis of Soil for all Three Zones

Contents
1. Zone 1...............................................................................................2
1.1 Ease of digging:.............................................................................2
1.1.1 Associated cost:.......................................................................2
1.2 Ground stability:............................................................................2
1.3 Retaining walls constructability, effectiveness and level differences.3
1.4 Managing risk of landslides and rock falls:......................................3
1.5 Footings:.......................................................................................4
1.5.1 Stiffened Raft Footings:............................................................4
1.5.2 Slab Footing:............................................................................5
2. Zone 2:..............................................................................................5
2.1 Ease of Digging and associated Cost:..............................................5
2.2 Ground stability:............................................................................6
2.3 Managing Level Differences, construction and effectiveness of
Retaining Walls...................................................................................6
2.4 Managing risk of Landslides and Rock falls......................................6
2.5 Footing Selection:..........................................................................6
2.5.1 Stiffened Raft footing:..............................................................6
2.5.2 Stiffened slab with deep edge beam footing:.............................7
3. Zone 3:..............................................................................................8
3.1 Ease of digging and associated cost:...............................................8
3.2 Ground Stability:............................................................................8
3.3 Managing Level Differences and Retaining Walls.............................9
3.4 Constructability and Effectiveness of retaining walls:......................9
3.5 Managing risk of landslides and rock falls:......................................9
3.6 Footing Selection:..........................................................................9
3.6.1 Stiffened Raft footing:..............................................................9
3.6.2 Waffle Rafts:..........................................................................10
4. Tabular comparison between Zone1, Zone2 and Zone 3......................11
5. List of References:............................................................................12

BUILDING STRUCTURE AND MATERIALS
ASSIGNMENT 2
1. Zone 1
1.1 Ease of digging:
As described zone 1 is a shallow valley and includes creek lines. There is also vegetation near
northern boundary and ground is swampy there throughout the year. On the basis of dig holes
zone 1 is classified as sandy soil with some clay layers and few gravel lenses. The sandy soils are
relatively easy to dig as compared to silty or clayey soil. Sand particles are very much larger in
size than silt and clay particle that’s why the gap between sand particles is larger too. There is no
cohesion between sand particles that why they are easy to dig. (1)
1.1.1 Associated cost:
The associated cost of excavation or digging is dependent on the total area to be excavated.
Larger the area to be excavated larger will be the cost. The area of the cut shown in the figure
can be calculated by
Area= h(2b + nh)
If we consider the cost of the same area
but for different type of soils then the
associated cost with sandy soil will be less
as they are easy to dig as compared to silt
and clayey soils.
1.2 Ground stability:
The ground movement or ground stability is dependent upon the physical properties and
environmental conditions like watering, climate and vegetation of soil. In zone 1 there is
vegetation at northern boundary and the site conditions are swampy there, that’s why for lighter
structure there might be ground movement and light structure can be destructive there. On the
basis of test pits Zone 1 is classified as sandy soil with some clay layers and gravel lenses.
According to standard AS 2870 if out site is class A then there would be 0 to 10 mm movement
but if our soil lies in class S then there would be 0 to 20 mm movement from moisture changes.

1.3 Retaining walls constructability, effectiveness and level differences
 Sandy soils are considered as best for using as a retaining material. In our case sandy soil
is having vegetation at some places which will act as reinforcement of sandy soil. Sandy
soils allow drainage in an effective way.
 A great observation regarding site elevation and grade changes are required to determine
the height of wall. To determine wall height a best practice is considered as “Start from
the lowest point and mark your grade changes in 1ft increment in plan”
 In construction of retaining wall, first we have to decide about the placement of wall so
we can determine that how much site we need to place or remove.
 When we cut site then it should be kept in mind that how should we utilize the excess soil
in an effective way.
1.4 Managing risk of landslides and rock falls:
Fine sedimentary sands and loesses are at risk to crumple when firmly inundated [e.g. by more
prominent than typical rainfall], or when subjected to solid seismic vibrations, or even a
vibrating roller. Subsequently, in that capacity materials are regular in Australia and abroad, it is
imperative to check the thickness and grain measure dissemination of the dirt, especially where
layers or pockets of fine sand and/or residue happen.
The dangers postured to building works by rockfall needs to date not been usually perceived;
nonetheless, the as of late expanded inclination to arrange/develop building works near bluff
lines and inside neglected quarry ranges has now made it important to truly consider the danger
of rock fall. The dangers emerge from the likelihood of a stone tumbling from over the site onto
the proposed constructing structure, or from a rock fall underneath the site expelling a portion of
the support to the building balance framework. (2)

1.5 Footings:
1.5.1 Stiffened Raft Footings:
According to the standard AS 2870 sandy soils are classified as class A. As specified in clauses
3.2.2, 3.2.4 and 5.3 stiffened raft footing can be used for class A and class S. The dimensions of
footings are shown in millimeters in fig
Table1: Stiffened Raft Footings Designs for Class A:
Site class Type of
constructio
n
Edge and Internal Beams
depth
Bottom reinforcement Top bar
reinforcement
Max
spacing
Mesh Bar
Alternativ
e
Class A
Clad frame 300 3-L8TM 2N12 ------- -------
Articulated
Masonary
veneer
300 3-L8TM 2N12
------- -------
Masonary
veneer
300 3-L8TM 2N12 ------- --------
Articulated
Full
Masonary
400 3-L8TM 2N12
-------- --------
Full
Masonary
500 3-L8TM 2N12 --------- ---------
Fig 1: Stiffened raft footing Dimensions for class A and S

1.5.2 Slab Footing:
Footing slab can also be used for class A and class S soils. Footing slab dimension are shown in
fig below
In case of dune sands a proper compaction is required before using these footings. (3)
2. Zone 2:
2.1 Ease of Digging and associated Cost:
As described zone 2 has a sloppy area with sparse trees in the zone. On the basis of test pits zone
2 is designated as clayey soil. Clayey soils are cohesive in nature and the space between clay
particles is smaller. That’s why clayey soils are harder to excavate as compare to sandy soils.
The Associated cost of excavation is dependent on site physical conditions and soil type. In
present case there are some trees in zone 2 and also the site is sloppy about 10 to 15 degrees.
That’s why removal of trees and leveling of site will cost extra and it will increase the associated
cost for digging of Zone 2 Soil. Therefore associated cost of zone 2 soil will be higher as
compared to zone 1 soil. (4)
Fig 2: Footing Slab for class A and class S
sites

2.2 Ground stability:
According to standard AS 2780, a higher probability of damage can occur due to abnormal
moisture content conditions. Presence of trees and removal of trees before construction or after
construction can cause soil movement and effect on foundation.
In present case, zone 2 soil is classified as Class M soil. According to AS 2870 for Class M soil,
moderate ground movements from moisture changes are considered to be 20 to 40 mm.
2.3 Managing Level Differences, construction and effectiveness of Retaining
Walls
 Clayey soils do not allow water to drain through them because pores spacing is low in
clayey soils. Clayey soils cannot be used as a retaining material because they do not
allow drainage of water and if they are used as retaining material water will start
accumulating on these soils and the pressure exerted on retaining walls will become
higher that will ultimately result to a failure of retaining wall.
 A great observation regarding site elevation and grade changes are required to determine
the height of wall. In present case Zone 2 soil is having a slope of 10 to 15 degrees.
 Before construction the subgrade should be compacted and level enough to take the load
of proposed building.
 In zone 2 clayey soil is present here therefore natural slope can be used for water
drainage purposes. (5)
2.4 Managing risk of Landslides and Rock falls
In present case the site is sloppy up to 10 to 15 degrees. This slope is enough for the free
movements of big size rocks. Therefore proper retaining walls must be built along road
side and heavy boulder should be removed during excavation process. In case of heavy
storm roads jointed to such boundaries must be closed for transportation to avoid major
accidents.
2.5 Footing Selection:
2.5.1 Stiffened Raft footing:
Stiffened raft footing as shown in the fig 1 can be used for class M soils with the
following design Details:

Table 2: Design of Stiffened raft footing for type M soil
Site class Type of
construction
Edge and Internal Beams
Depth
Mm
Bottom reinforcement Top bar
reinforcemen
t
Max
spacing
Cc m
Mesh Bar
Alternative
Class M
Clad frame 300 3-L11TM 3N12 ------- 6
Articulated
Masonary
veneer
400 3-L11TM 3N12
-------
6
Masonary
veneer
400 3-L11TM 3N12 ------- 5
Articulated
Full
Masonary
625 3-L11TM 3N12 2N12 4
Full
Masonary
950 2x3-L11TM 3N16 2N16 4
2.5.2 Stiffened slab with deep edge beam footing:
This type of footing can be used for class M soil with masonry veneer or articulated
masonry veneer construction. Beam spacing for veneer construction shall not exceed 5 m
and for articulated veneer must not exceed by 6 m. (6)

3. Zone 3:
3.1 Ease of digging and associated cost:
As described, zone 3 is steeper as compared to zone 1 and 2. Zone 3 soils is classified as class S
soil. Class S soil will be easy to dig as compared to zone 2 soil but it will be harder to dig as
compared to zone 1 soil. Since class S soil is containing clayey with top layer of sand that’s why
top surface allows drainage but bottom surface do not.
There are no trees found on the zone 3 site and there is also not any water table that’s why
associated cost will be less as compared to zone 1 and zone 2.
3.2 Ground Stability:
Ground stability relies upon the physical conditions and environmental conditions like watering,
vegetation and climate etc. there is no vegetation on zone 3 soils so there are no chances of
Fig 3: Stiffened Slab with Deep Edge beam Footing

abnormal behavior of moisture content. Therefore soil will be stable against sudden moisture
content changes.
According to standard AS 2870 class S soils show 0 to 20 mm surface movements from moisture
changes.
3.3 Managing Level Differences and Retaining Walls
 Zone3 site is very sloppy enough that no one can walk easily on it. Therefore for
construction purposes for zone 3 site it is necessary to make it level and prepare a
subgrade that can bear the required load with ease.
 Zone3 soil is classified as class S soil and it can be used as a retaining material with some
amendments. In the present situation there is a layer of sand above clayey soil. Sand layer
is permeable enough that it will drain the surface water but beneath clayey soil will be a
hurdle on its way. So the perfect solution is to provide pipes through clayey soil to end of
the retaining wall.
3.4 Constructability and Effectiveness of retaining walls:
 In construction of retaining wall, first we have to decide about the placement of wall so
we can determine that how much site we need to place or remove.
 When we cut site then it should be kept in mind that how should we utilize the excess soil
in an effective way.
 Retaining walls will prevent the falling of boulders and rock pieces on the roads.
 Raining water will also drain through the 30 degree slope with ease and it will enter into
the drainage lines by travelling through the retaining soil.
3.5 Managing risk of landslides and rock falls:
The given site is very sloppy that’s why probability of falling rock and landslide is higher in this
case. As described there is road on the contour lines of the zone3. That’s why risk assessment is
higher in this case as compared to zone 1 and zone 2. This risk can be managed by removing
boulders and rocks during excavation and also by building retaining wall at the boundary lines.
3.6 Footing Selection:
3.6.1 Stiffened Raft footing:
Stiffened raft footing as specified in Fig 1 can be used for type S soil with the design mentioned
in following table

Table 3: Design of stiffened raft footing for class S soil:
Site class Type of
construction
Edge and Internal Beams
Depth
mm
Bottom reinforcement Top bar
reinforcemen
t
Max
spacing
Cc m
Mesh Bar
Alternative
Class S
Clad frame 300 3-L11TM 2N12 ------- -----
Articulated
Masonary
veneer
300 3-L11TM 2N12
-------
-----
Masonary
veneer
300 3-L11TM 3N12 ------- -----
Articulated
Full
Masonary
500 3-L11TM 3N12 2N12 -----
Full
Masonary
700 2x3-L11TM 3N16 2N16 5
3.6.2 Waffle Rafts:
Waffle rafts can also be used as footing for class S soils. In garage areas a slab thickness of 85
mm should be use. (7)
Fig: Waffle raft Dimensions

Table 4: Design of Waffle raft for class S soil:
Site
class
Type of
construction Depth
mm
Bottom reinforcement Internal
Beam
Slab mesh
Slab Length
Mesh Bar
Alternative
<20m =20 m
and
>30 m
Class S
Clad frame 260 3-L8TM 3N12 1 N 12 SL 72 SL82
Articulated
Masonary
veneer
310 3-L8TM 3N12 1N12 SL72 SL82
Masonary
veneer
310 3-L8TM 3N12 1N12 SL72 SL 82
Articulated
Full
Masonary
385 3-L8TM 3N12 1N16 SL72 SL82
Full
Masonary
----- ------- ----- ------ -----
4. Tabular comparison between Zone1, Zone2 and Zone 3
Table 5: Tabular Comparison B/W zone1, zone2, and zone3
Items needed to
be addressed ZONE 1 ZONE 2 ZONE 3
Ease of digging Easier to dig Harder to dig Moderate to dig
Associated cost lowest Medium Highest
Ground movement 0 to 10mm 20 to 40 mm 0 to 20 mm
Level differences Flat surface 2 m level difference 2 to 3 m level difference
Retaining material Very effective Not suitable Moderately Effective
Proposed Footing  Stiffened Raft
footing
 Slab Footing
 Stiffened Raft
footing
 Stiffened slab
with deep
 Stiffened Raft
footing
 Waffle Rafts