Elimination of Geotechnical Risks of the Landfill Body Situated on the Spoil Heap by Monitoring

As standards of living rise, so does the amount of waste produced and the need to dispose of it. Landfill is still the most common method of waste disposal. Brownfield sites, especially tailings piles, are well suited for this purpose. Landfills can cause significant damage to their surroundings, so geotechnical and environmental risks must be eliminated. Proper monitoring should be used to prevent this from happening. Local depressions up to 15 m deep have been used in the spoil heap area of a surface coal mine. Due to the nature of the materials in the spoil heap, the approach to geotechnical monitoring of the proposed construction needs to be different from the conventional one. Undoubtedly, the low permeability of spoil heap material is one of the most positive features: In the lower, fully consolidated parts, there are impermeable soils. However, spoil heaps consolidate slowly and can cause uneven deformation, particularly surface settlement. There are associated geotechnical risks of damage to the sealing elements of the landfill. It is therefore appropriate to monitor the deformations of the bottom of the landfill body. Prior to the construction of the landfill, altimeter sensors were installed at the site of interest to measure the relative movements of the landfill floor in relation to the location of the reading unit. A geodetic survey of the site (fixed points around the landfill) can be used to determine the movements of the entire heap. Uneven settlement can be documented from these absolute movement values. Spoil heap materials tend to be unstable; therefore, proper monitoring should be supplemented by numerical methods (stability calculations) to prevent landslides. The geotechnical risks associated with the disposal of waste in landfills under such anthropogenic conditions should be eliminated by unconventional geotechnical monitoring, including the measurement of deformations of the landfill bottom and continuous recalculation of stability.