Chapter 5: Information about the subsurface
The underground is largely a hidden realm. Without special tools, it cannot be directly observed and specific, geological knowledge is necessary to understand its structure and properties. In the past, understanding the behaviour of the underground was based solely on experience gained by trial and error. In the twentieth century, science and (geo-)technology introduced the tools and methods to identify and understand the groundmass properties necessary to develop sustainable, safe and stable underground constructions. Knowledge of the subsurface through sound data and information is a prime requirement for realizing such constructions that do not jeopardize existing structures or interfere with current types of land-use. This chapter describes how to obtain sub-surface data and information and how to handle such information to arrive at reliable models to predict behaviour of underground constructions based on engineering geological knowledge and expertise.