A geogrid-reinforced landslide stabilization: 20 years passed
In spring 1994 a landslide occurred on a natural slope of about 25 m height just below a ski-lift station in the Austrian Alps near Lech. The slid soil mass blocked the road at the toe of slope. The upper part of the sliding surface reached the foundation of the lift station on top of slope destroying the earth platform in front of the station and endangering the entire building. A quick solution for the slope reconstruction and stabilization had to be developed and executed before the beginning of the next ski season in September. The solution had to meet a wide range of requirements, some of them caused by the specific position in the high mountains. Finally, a geogrid-reinforced full-height slope was designed and constructed reusing the local soils and reconstructing approximately the former natural slope shape before the failure. Note, that at that time the experience with such structures was still modest, some decisions were a bit risky due to the lack of knowledge and were based on engineering judgement. The System was successfully built in less than two months and is still stable after twenty years of Service, say twenty season cycles winter-summer in the Alps. The Problems, boundary conditions, philosophy and design from 1994 are described together with the unknown factors and specific solutions, and the construction technology and experience as well. The current state is shortly described and commented.
It seems that the geogrid-reinforced landslide stabilization structure designed and built in 1994 proves to be generally a successful, efficient and durable solution despite a number of specific disadvantageous circumstances in 1994. In our opinion this demonstrates the flexibility and robustness of geosynthetic-soil structures. It is may be the first geogrid application for rehabilitation and stabilization of a landslide. It is worth to notice that in comparison to today even the design procedures and tools were in 1994 very modest and had to be substituted often by engineering judgment. In our understanding the positive experience gained should encourage the intensive application of such solutions nowadays especially in consideration of the globally increasing landslide problems due to climate Change.