Chapter 11 Managing groundwater in the engineering design and construction of subsurface works

This chapter addresses the significant challenges encountered in constructing engineering works below groundwater level, particularly in deep subsurface projects such as shafts and tunnels. It explores how groundwater interaction can lead to decreased water levels, surface settlement and potentially severe inflows that disrupt excavation progress and destabilize the construction site. These issues may also cause environmental damage and affect nearby structures. The chapter outlines two primary strategies for groundwater control. The first strategy involves preventing water ingress by enhancing ground impermeability or installing physical barriers such as diaphragm walls. Alternatively, adjusting groundwater gradients using techniques such as earth pressure balance machines during tunnel excavation is discussed. The second strategy focuses on actively lowering water levels through pumping or passive drainage to manage groundwater effectively. The requirements for long-term weathertightness of underground structures and possible strategies are also discussed.