18. Define soil mechanics and its importance in civil engineering. (3 marks) 19. Describe the different types of soil and their properties. (3 marks) 20. What is the significance of the Atterberg limits in soil classification? (3 marks) 21. Explain the concept of soil compaction and its methods. (3 marks) 22. What are the different types of foundations used in construction? (3 marks) 23. Describe the concept of bearing capacity of soil. (3 marks) 24. Explain the importance of site investigation in geotechnical engineering. (3 marks)