A landfill with innovative reinforcing solutions: history, experience, solution flexibility/Un ISDN avec solution de renforcment innovante: histoire, expérience, solutions flexible
A landfill in a mountainous region of Austria is embedded on a hillside. This results in an unusual geometry of the planned 75 m high landfill body: one third of the basal system is almost horizontal and two thirds are inclined following the excavated slope in the hill. In the early 90's the basal system was installed in the horizontal section and on two of the lowest slope sections and infill of municipal waste started. In 1994 doubts were raised regarding the local and global stability. High-strength low-strain geogrids from Aramid (AR) were installed in 1995-1996 on the two lowest slope sections as "anti-sliding" reinforcement. In the late 90ies the infilling of municipal waste almost stopped. In 2013 the owner decided to reactivate the landfill and to deposit construction debris and/or ashes on top of the old municipal waste, up to the planned height of 75 meters. Multiple stability analyses were performed resulting in a solution with further strong low-strain "anti-sliding" geogrid reinforcement on the slope sections, above those already reinforced in the 90's, and in multilayered geogrid reinforcement with a tensile strength of up to 1200 kN/m directly in the new fill. The general situation, solution and experience from 1994-1996 are presented followed by a description of the situation, philosophy, design analyses and solutions today demonstrating how innovative geosynthetic reinforcements can help to solve specific landfill stability problems.
The landfill Böschistobel in Austria was constructed and put into operation at the beginning of the 90ies as a landfill exclusively for municipal waste. Geometry and position in a hilly area are quite specific. In 1995-1996 aramid geogrids with up to 1200 kN/m strength were installed as "anti-sliding" reinforcement to ensure the global sliding stability of the entire waste body. A measurement program confirmed the plausibility of the solution. Then for about 15 years the landfill had been practically inactive. A reactivation era started in 2013 for other types of waste. New series of stability calculations were performed varying waste disposal scenarios, failure modes and infill stages. Based on the positive experience in the 90ies in terms of efficiency and proper system behaviour, geogrid solutions were taken into consideration again. High-strength geogrids from Polyvinylalcohol (PVA) and Polyester (PES/PET) with up to 1600 kN/m strength are foreseen and started being installed.