Pressure sensitive grouting (PSG) in tunnelling using Fuzzy Logic to control the grouting process

In tunnelling grouting of rock becomes more and more important. Especially if waste is stored in rock deposits the question of how to seal the cracks and make them watertight will arise immediately. To understand the fluid flow of grouting materials in narrow joints physical and numerical models were investigated. As it is impossible to explore rock mass structure on the whole (number and width of joints, gouges, rock material behaviour etc.), it is not possible to dimension grouting processes in a classical sense. A Fuzzy Logic procedure is used to determine whether or not grouting leads to unwanted and dangerous fracture extensions in rock. The criteria which control the Pressure Sensitive Grouting (PSG) are the pressure drop, the residual pressure, the pressure - grouting volume ratio and the time dependent behaviour. This ''design as you go'' philosophy has the advantage of including the rock mass and the grouting material behaviour in an integral sense.