Final answer:
For standard foundation excavation, a backhoe is often the best choice because of its versatility. A bulldozer is suitable for larger jobs, a Bobcat for smaller or tight areas, and a grade-all for very large projects. The size of the rocks present should also be considered when selecting equipment.
Step-by-step explanation:
The best piece of equipment for removing topsoil for the excavation of a foundation depends on the scale of the work and the amount of material to be moved.
For a standard job, a backhoe is often the best choice. Backhoes are versatile machines that have both a digging bucket on the back and a loader bucket on the front, which makes them ideal for digging out earth for a foundation while also having the capacity to move large amounts of topsoil efficiently.
If you are dealing with a larger area and need to clear a significant volume of earth quickly, a bulldozer might be more appropriate. Bulldozers have powerful blades which can push a lot of soil in a relatively short time. On the other hand, a Bobcat, which is a type of skid-steer loader, can be beneficial for smaller jobs or for tight spaces where larger equipment cannot maneuver well.
For very large projects, a grade-all or a gradall, which is a wheeled excavator with a telescoping boom, could be the most efficient for moving large amounts of earth over different terrains. However, it's crucial to assess the size of the boulders or rocks present on the site, as larger rocks may require special consideration.