Upper Bound Analysis for Collapse Failure of Shield Tunnel Face Excavated in Unsaturated Soils Considering Steady Vertical Flow

Table 2

Comparison of the collapse pressure with experimental results.

Tunnel diameter ()	5	10	13
Experimental results	3.3	7.4	13.4
and	7.16	16.70	22.43
and	6.30	14.81	19.92
and	4.78	14.32	20.04
and	4.07	12.59	17.70