Geotechnical State CRITICAL
Factor of Safety (FoS):
0.74
Scour Trench Depth:
3.60 m
Toe Erosion Rate:
1.45 m/hr
Structural Tipping Angle:
18.4°
Elapsed Surge Duration:
42 s
FAILURE MECHANISM:
Toe scour undercut triggering retrogressive circular slip and eccentric toppling
Foundation Bearing Monitor
Hydraulic Bed Shear (τ):
46.2 Pa
Critical Shear Stress (τc):
14.8 Pa
Pore Water Saturation:
94 %
Collapse Observed:
YES (TRUE)
Case Background: Fujian Saudel Collapse
In October 2020, outer rainbands from Typhoon Saudel produced torrential cloudbursts across southern China. Swollen river runoff combined with intense hydraulic shear stress (τ = ρ g R S) aggressively undermined alluvial embankments.
As the bank toe was eroded beyond the foundation embedment depth, bearing capacity dropped eccentrically, precipitating a retrogressive rotational slip that dropped multi-story masonry dwellings directly into the torrent.