Soil and rock reinforcements in tunnelling

Abstract Soil and rock improvement and reinforcement techniques are used to permit safe tunnel excavations in difficult geological conditions. The main methods are ground reinforcement, grouting, jet grouting, drainage, freezing, and mechanical precutting. The improvement methods are divided into two basic groups—improving interventions and preserving interventions. A critical analysis is of these methods given and a technical comparison between the main improvement techniques adopted in tunnelling is shown. Several ground reinforcement schemes are discussed. Examples from Italy of the various types of ground improvement and reinforcement techniques are given.