ABSTRACT
In tunnelling, a method based on the modulus of subgrade reaction is often used to design tubbing elements and the (cast-in-place) concrete inner lining. To this end, the modulus of subgrade reaction is an important parameter. As early as 1980, the “Recommendations for the calculation of tunnels in soft rock” were published by the German society for earthworks and foundation engineering, in which standard approaches for the modulus of subgrade reaction were specified and which are still used widely today. At the time, it was said: “With numerical calculation methods non-linear material laws for the soil and lining can also be taken into account”. However almost 40 years later, the subgrade reaction modulus method is frequently used in favor to more recent numerical methods. This article questions whether the assumptions and principles of the subgrade reaction modulus method are still up-to-date.
