Dewatering, Waterproofing and Drainage

The removal of groundwater through practical dewatering remains one of the most important tasks in the construction of underground structures. In order to be able to plan the nature and extent of dewatering measures in advance, geological, hydrological und chemical investigations have to be undertaken to determine the quantity and properties of water ingress to be expected. Waterproofing technology for underground tunnels has been developed from many years of experience with roof waterproofing, waterproof troughs for buildings and industrial facilities and the waterproofing of cut-and-cover tunnels. This chapter shows the basic principles of three types of drainage systems for protecting a tunnel against damp or water ingress: construction without drainage, pressure-regulated drainage, and free drainage. The chapter then presents a brief introduction to the causes of sintering, the design, construction and maintenance of drainage systems, and discusses the central differences between the two most prominent approaches – German and Austrian.