Grade 10 building construction β Site Preparation Quiz
1. What is the main purpose of clearing vegetation and topsoil during site preparation for a building foundation?
Clearing vegetation and topsoil removes organic material that decomposes and causes settlement, and creates a stable surface for foundation works.
2. Before excavating for foundations, which action is most important to avoid hitting underground services?
Locating and marking utilities prevents damaging water, electricity, or sewer lines, which is essential for safety and avoiding costly repairs.
3. Why is conducting a test pit or trial hole important during site preparation?
Test pits reveal soil properties and ground conditions so engineers can design suitable foundations and plan dewatering if needed.
4. Which soil type is known in Kenya for causing swelling and shrinking that can damage foundations?
Black cotton soil expands when wet and shrinks when dry, causing movement that can crack foundations if not treated or avoided.
5. What is the best practice for storing topsoil removed from a building site?
Topsoil should be stored separately for reuse in landscaping; it must not be used under foundations or dumped in drains.
6. During site preparation, what is the purpose of setting out the building position?
Setting out ensures the building is built in the right place and orientation by transferring dimensions from the plan to the site.
7. Which measure helps control erosion and runoff during site preparation on a sloping site?
Erosion control measures like silt fences and contour drains slow runoff and prevent soil loss and sediment polluting waterways.
8. What is the correct action if groundwater is encountered in foundation excavations?
Groundwater must be managed to prevent weak base conditions; dewatering or alternative foundation design ensures stability and safety.
9. When balancing cut and fill on a site, what is the aim?
Cut-and-fill balance reduces transport costs and environmental impact by using onsite material to level the site when possible.
10. Why should trees and large stumps be removed beyond the foundation line during site preparation?
Tree roots can decay leaving voids or draw moisture from soil causing shrinkage; removal beyond foundation line prevents future problems.
11. What is the reason for compacting subgrade soils under a foundation?
Compaction increases density and bearing capacity of the subgrade, reducing settlement and ensuring a stable base for foundations.
12. Which Kenyan authority should builders consult about environmental impact before major site works?
NEMA oversees environmental impact assessments and regulations to ensure site works comply with environmental laws.
13. Why is it important to provide safe site access and traffic management during site preparation?
Controlled access and traffic plans reduce accidents, protect pedestrians, and ensure smooth delivery and removal of materials.
14. What should be done with surface water collected on a construction site during preparation?
Temporary drainage and settling pits control water, prevent trench collapse and reduce sediment leaving the site.
15. Which safety measure is essential around open foundation excavations?
Barriers, signs and safe access prevent falls and allow safe entry/exit for workers, reducing accidents.
16. Why must topsoil not be used as backfill under strips or pads of foundations?
Organic components in topsoil decompose and compact over time, leading to uneven settlement under foundations.
17. What is a soakaway used for on a building site?
A soakaway is a pit filled with stone that lets surface water soak into the ground, reducing runoff and flooding.
18. During site preparation, why is it important to check site boundaries and title before setting out?
Verifying boundaries prevents building on another person's land and avoids legal disputes and possible demolition orders.
19. What is the correct response if hazardous materials (like asbestos) are found during site clearance?
Hazardous materials must be handled by specialists and disposed of safely to protect health and comply with regulations.
20. Which tool is commonly used to check levels during site preparation for foundations?
Levels like spirit levels or dumpy levels are used to set correct elevations and ensure foundations are level and at the right depth.
21. Why should spoil (excavated material) not be piled too close to the edge of an excavation?
Spoil placed near edges adds weight and can cause trench collapse, endangering workers and equipment.
22. Which of the following is a key reason for compacting fill in layers (lifts) rather than all at once?
Compacting fill in thin layers allows even compaction, better strength and less long-term settlement than thick uncompacted fills.
23. What should you do if a steep slope is present on the building site before foundation work begins?
Steep slopes need earthworks or retaining solutions to create a safe stable area for foundations and prevent landslides.
24. Which document or plan should be available on site to guide correct foundation location and dimensions during setting out?
Approved plans provide accurate dimensions, positions and authorities' approval; they are essential for correct setting out and compliance.
25. Why is it important to protect trees that are to be retained during site preparation?
Protecting roots and preventing compaction preserves tree health and avoids root decay that could later affect the building.
26. Which practice helps reduce dust and nuisance during dry site clearance in Kenya?
Watering dust and wheel-wash bays reduce airborne dust and prevent dirt being carried onto public roads, meeting good site management.
27. What is the main purpose of site clearing before starting foundation works?
Site clearing removes trees, shrubs, roots and debris so construction can proceed safely and foundations rest on a stable, unobstructed area.
28. Which Kenyan authority should be consulted for environmental approvals on a construction site?
NEMA is the statutory body in Kenya responsible for environmental impact assessments and approvals for construction projects.
29. What is the purpose of removing topsoil during site preparation for foundations?
Topsoil is rich in organic material and compressible; removing it ensures foundation rests on stronger subsoil or compacted engineered fill.
30. Why is a site survey and setting out important before excavation?
Surveying and setting out transfer the building layout and levels from drawings to the ground, ensuring correct position and alignment of foundations.
31. What is a trial pit used for in site preparation?
Trial pits allow visual inspection and sampling of subsoil to determine suitability and depth for foundations and need for special measures.
32. Which test gives an indication of soil bearing capacity on site commonly used in Kenya for shallow foundations?
The plate load test measures settlement under controlled loading and is commonly used to estimate bearing capacity for shallow foundations.
33. During site preparation, why is it important to check the water table level?
High groundwater can affect bearing capacity, cause buoyancy (uplift), and require pumping or special foundation designs.
34. What is the purpose of benching or profiling in sloping sites before foundation works?
Benching or terracing a slope forms stable working platforms and reduces the chance of landslip or uncontrolled collapse during foundation works.
35. Why must spoil (excavated material) be stored away from the edge of excavations?
Spoil heaps close to excavation edges add pressure and can trigger sloughing or collapse, endangering workers and works.
36. What is the main reason to provide temporary drainage during site preparation?
Temporary drainage channels and pumps keep excavations dry, reduce delays, and prevent weakening of soil that supports the foundation.
37. Which of the following is a safe practice when excavating deep foundation trenches?
Shoring or sloping reduces risk of collapse and is required for worker safety when trenches are deep or in unstable soils.
38. What does compaction of fill beneath a foundation achieve?
Proper compaction removes air voids, increasing density, strength and reducing future settlement beneath the foundation.
39. Why should building setbacks and boundary positions be checked during site preparation in Kenya?
Checking setbacks ensures the structure complies with local planning regulations and avoids legal disputes with neighbours or authorities.
40. What role does a geotechnical report play in foundation site preparation?
A geotechnical report contains results of soil investigations and recommendations for foundation type, depth and construction methods.
41. Which method is commonly used to prevent erosion and sediment runoff during site preparation in rainy seasons?
Silt fences and sediment controls trap soil and reduce sediment-laden runoff, protecting nearby drains and watercourses.
42. When is dewatering required during foundation excavation?
Dewatering pumps or wells are used when groundwater enters excavations, affecting stability and making construction unsafe or impractical.
43. What is the purpose of marking utility lines before excavation?
Locating and marking existing utilities prevents dangerous and costly strikes to pipelines and cables during excavation.
44. Which of the following should be done with trees that must be removed from a foundation area?
Tree roots left under foundations can rot and cause voids or heave; removing roots from the footprint prevents future problems.
45. Why is it important to compact the base of an excavation before laying concrete footing?
A well-compacted base minimizes differential settlement and ensures the footing bears evenly on supporting soil or engineered fill.
46. What is 'benching' used for in excavation on a steep site?
Benching involves cutting stepped levels into a slope to reduce risk of collapse and to form safe levels for construction activity.
47. Why is it important to protect adjacent properties during site preparation?
Protecting neighbouring properties from damage and disturbance reduces risk of disputes and complies with construction best practice and law.
48. Which of the following best describes 'setting out' in building construction?
Setting out transfers the design onto the ground using pegs and lines so foundations and walls are built in the correct place.
49. What is one environmental consideration during site preparation in Kenya?
Minimising sediment runoff and preserving vegetation where possible protects ecosystems, complies with NEMA and prevents erosion.
50. What should be done if contaminated soil is discovered during site preparation?
Contaminated soil can pose health and structural risks; proper testing and remediation ensures safety and legal compliance.
51. Which protective measure is important to ensure worker safety on an excavation site?
Barriers, clear signage, safe ladders/ramps and PPE reduce the risk of falls, trips and injury on excavation sites.