Influence of Tunneling in Cohesionless Soil for Different Tunnel Geometry and Volume Loss under Greenfield Condition

Table 3

Details of tunnels in sands and maximum surface settlement, s_max.

No.	Source	Location	Ground conditions	Excavation methods	Tunnel diameter (m)	Depth to tunnel axis H, (m)	Volume loss VL (%)	Inflection point, I (m)	Maximum settlement along tunnel center line, Smax, (mm)
									Measured	PLAXIS	Empirical approach [3]
1	[30]	London, UK	Medium to coarse sand with some gravel	Bentonite shield	4.1	10.1	0.9	5.0	22	18.5	17.3
2	[31]	Washington, USA section a	Medium dense silty sand	Shield articulated with digger arm	6.4	20.9	0.1	5.1	6	7	2.23
3	[32]	Ayrshire, UK; Joint drainage scheme	Loose silty sand with little gravel	Shield hand excavated	2.9	5.7	0.77	1.6	16	17.4	13.5
4	[33]	Tokyo, Japan site III	Fine silty sand	Blind shield	3.7	22.1	2.1	8.2	32	30.6	29.1
5	[31]	Illinois, USA Rockford, Illinois	Medium dense sand with some gravels	Mechanical shield	3.0	10.8	2.9	2.0	25	26.7	27.9
6	[3]	Warrington, UK	Loose and silty sand	Shield, hand excavated compressed air	2.0	8.4	3.9	3.2	28	25.0	21.6
7	[14]	Taipei, Taiwan	Silty sand	EPBM	6.1	18.5	1.0	7.4	26	23.9	22.9