4.1 The excavation of soil on a building site is necessary to establish a firm foundation - NSC Civil Technology Construction - Question 4 - 2019 - Paper 1
Question 4
4.1 The excavation of soil on a building site is necessary to establish a firm foundation.
4.1.1 What is the minimum distance that excavated soil can be stored from... show full transcript
Worked Solution & Example Answer:4.1 The excavation of soil on a building site is necessary to establish a firm foundation - NSC Civil Technology Construction - Question 4 - 2019 - Paper 1
Step 1
What is the minimum distance that excavated soil can be stored from the trench?
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Answer
The minimum distance that excavated soil can be stored from the trench is 600 mm. This ensures that the soil does not exert undue pressure on the trench walls, reducing the risk of collapse.
Step 2
What is a safe distance for heavy machinery to move around a deep excavation?
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Answer
A safe distance for heavy machinery to move around a deep excavation is 1 meter. This distance helps to safeguard both the operators and the stability of the excavation.
Step 3
Describe TWO reasons why an excavation can collapse.
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Heavy rains can saturate the soil, leading to a reduction in stability and increasing the likelihood of a collapse.
Poor soil composition or structure can undermine the walls of the excavation, making them more susceptible to failure.
Step 4
What is the maximum depth of a trench in which workers can work without the sides of the trench being braced?
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The maximum depth of a trench in which workers can work without the sides being braced is 1.5 meters. Depths exceeding this require proper bracing to ensure worker safety.
Step 5
What can help to prevent the sides of excavations from collapsing?
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To prevent the sides of excavations from collapsing, it is essential to use proper shoring techniques. Additionally, regular inspections should be conducted to identify and rectify any signs of instability.
Step 6
A- Will be used in shallow trenches/loose soil.
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The type of shuttering described in part A will be used in situations where the trench depth is shallow or the surrounding soil is loose, requiring adequate support to maintain excavation integrity.
Step 7
B- Will be used in firm soil.
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The type of shuttering described in part B is designed for use in firm soil, providing robustness and ensuring that the excavation remains stable under those conditions.
Step 8
C- Poling boards.
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Poling boards are used to support the walls of an excavation, stabilizing the structure and preventing collapse.
Step 9
D- Walling boards.
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Walling boards are essential components in the construction of formwork for trenches, helping to delineate the boundaries and provide structural integrity.
