What type of filter is used under the construction entrance to stabilize the stone pad?

The use of a fabric filter underliner under the construction entrance is specifically designed to stabilize the stone pad and prevent the migration of fine particles from the subgrade into the stone. This type of filter allows water to flow through while restricting the movement of sediment and soil, ensuring that the stone remains stable and effective in minimizing erosion and sediment movement off-site.

The fabric filter provides a permeable barrier that helps maintain the integrity of the stone pad by supporting its structure while filtering out any smaller particles that could compromise its effectiveness. This is essential in construction sites where soil disturbance can lead to increased runoff and sedimentation, affecting both the immediate site and surrounding areas.

Other types of filters mentioned, such as water filters, sand filters, and oil filters, serve different purposes and are not suitable for this specific function. For example, water filters are generally used in applications that require purification of drinking water, sand filters are more commonly associated with treating stormwater by capturing sediments and pollutants in a different manner, and oil filters are related to vehicles and machinery to keep engines free from contaminants. Therefore, the fabric filter underliner is the correct solution for stabilizing the stone pad at a construction entrance.