Table 2. Mechanisms and case studies of... | Emerald Publishing

Table 2.

Mechanisms and case studies of environmental impacts on underground infrastructure

Mechanisms of impact	Description	Case studies
Material expansion and stress	Thermal expansion causes stress in tunnel structures, leading to cracking	London Underground: Heat-related cracking and retrofitting needs (Nicholson et al., 2014).
Performance under heat stress	Heat misalignments and stress cracks in rail tunnels reduce safety	London Underground: Misalignments during heatwaves require fixes (Steen et al., 2022).
Freeze–thaw cycles	Freeze–thaw cycles, cause frost heave, leading to settlement and damage	Norwegian tunnels: Frost heave damages linings and pavements (Aursand, 2013).
Soil dynamics during thawing	Thawing permafrost destabilises soil, causing tunnel distortion	Sub-arctic tunnels: Thawing causes uneven settlement and damage (Kurylyk et al., 2014).
Heat retention in enclosed spaces	Poor ventilation retains heat, compromising structure and comfort	Singapore metro: Heat stress from poor ventilation (Acero et al., 2022).
Energy demands for cooling	Extreme heat raises cooling needs, creating operational inefficiencies	High cooling costs in extreme heat (Goel et al., 2012).

Mechanisms of impact	Description	Case studies
Material expansion and stress	Thermal expansion causes stress in tunnel structures, leading to cracking	London Underground: Heat-related cracking and retrofitting needs (Nicholson et al., 2014).
Performance under heat stress	Heat misalignments and stress cracks in rail tunnels reduce safety	London Underground: Misalignments during heatwaves require fixes (Steen et al., 2022).
Freeze–thaw cycles	Freeze–thaw cycles, cause frost heave, leading to settlement and damage	Norwegian tunnels: Frost heave damages linings and pavements (Aursand, 2013).
Soil dynamics during thawing	Thawing permafrost destabilises soil, causing tunnel distortion	Sub-arctic tunnels: Thawing causes uneven settlement and damage (Kurylyk et al., 2014).
Heat retention in enclosed spaces	Poor ventilation retains heat, compromising structure and comfort	Singapore metro: Heat stress from poor ventilation (Acero et al., 2022).
Energy demands for cooling	Extreme heat raises cooling needs, creating operational inefficiencies	High cooling costs in extreme heat (Goel et al., 2012).