Foam Concrete: A State-of-the-Art and State-of-the-Practice Review

Table 9

Application examples of selective fill with FC.

Reference	Tunnel name	Country	Year	Application	Brief descriptions
[235]	Kent Thameside tunnels	UK	2010	Reclamation	The 50 m deep tunnel extends about 90 m, and FC with density of 400 kg/m^3 and compressive strength of 0.5 MPa was backfilled.
[236]	Dakota Project	USA	2000	Reinforcement backfill	The original granular backfill above the tunnel resulted in foundation foot settlement and finally caused structure deformation. The original filling was removed and replaced by 500 kg/m^3 FC.
[237]	Farnworth	UK	2015	Auxiliary construction	The 7800 m^3 FC of 1100 kg/m^3 and 1 MPa was used to backfill the one of a 300 m long double-hole tunnel so as to accept the Tunnelling Boring Machine (TBM).
[235]	Thackley	UK	2013	Structural reinforcement	As more distortion was recorded, with the crown being forced upwards into a void. A total 2540 m^3 FC with 1120–1130 kg/m^3 and 1 MPa was required for fillers.
[238]	Huashiya	China	2015	Cavity filling	Cavities and cracks appeared in secondary liner of tunnel, and then these defects were filled by FC grouting.
[235]	Gerrards Cross project	UK	2009	Load reduction	To reduce dead load, pile walls were installed on both sides of the tunnel, and 26,000 m^3 FC with 375 kg/m^3 was used to form horizontal ground at the top of vault.
[239]	Wulaofeng	China	2009	Seepage water treatment	The seepage of tunnel side wall was serious, and some locations were even gushing, so FC was used as waterproof material.