Design and construction of geosythetic reinforced “slopes and walls”: commentary and selected project examples
Slopes very often have to be formed steeper than the shear strenght of their soils alone would allow. For abrupt (artificial) changes in ground levels this problem has long been solves by constructing retaining walls (mainly vertical) or similar support systems of various types and different materials (masonry, mass concrete, reinforced concrete etc.). At the start of the 1960s Henri Vidal developed the concept of "reinforced earth" In which he was the first to reinforce earth using horizontal steel strips ans form the external face with vertical panels. In the meantime this idea has undergone considerable further development to inclined vertical (or steeply inclined) earth supporting structures with horizontal, multilayer geosynthetic reinforcement over the full plan area ("full coverage") and different external skin systems (facings). The many advantages of "GRS" = (Geosynthetic Reinforced Soil) include cost savings (GRI 1998) and have meant that it has become an increasingly adopted and well established solution. In many cases it is not absolutely necessary to construct vertical or almost vertical earth retaining structures. Often it is enough to form the slopes at an inclination of typically 50° to 70° to the horizontal in order to produce a stable slope , which without additionally incorporated measures ( such as geosynthetic reinforcement), would not be stable. These types of structures are usually referred to as "(steep) reinforced slopes".
Geosynthetic-reinforced steep retaining systems have established themselves in Europe over recent years because of their economic, aesthetic, ecological and constructional (technological) advantages. In addition, they are very flexible and adaptive in shape and behave, in terms of soil mechanics, as ductile system. In analysis and design there are often two potentially critical modes of failure to cooperation.