What can be added to the top of a buried tank to offset buoyancy?

Adding concrete to the top of a buried tank effectively offsets buoyancy because concrete is heavy and dense. When a tank is buried underground, it is subject to buoyant forces, especially if the ground becomes saturated with water or if the tank is filled with air. This buoyant force can potentially cause the tank to float or shift, which can lead to structural damage or environmental issues.

By placing a layer of concrete on top of the tank, the weight of the concrete counteracts the upward buoyant forces. This added weight ensures that the tank remains securely in place, thereby preventing it from moving or rising due to buoyancy. Concrete is advantageous in this scenario because it adheres well, is resistant to weathering, and can provide a stable and long-lasting solution to the problem of buoyancy in underground storage tanks.

While other materials like gravel, water, or sand may provide some level of weight, they do not offer the same degree of stability or permanence as concrete. Additionally, using water does not add weight in a way that addresses buoyancy effectively since it may simply create a new buoyant force if the water level changes.