Research Article

Upper-Bound Finite Element Adaptive Analysis of Plane Strain Heading in Soil with a Soft Upper Layer and Hard Lower Layer

Table 2

Critical surcharge loading σs for soft 2.

Position of soil interfaceσs (kPa)
C/D = 1C/D = 2C/D = 3C/D = 4

Case 1222.36639.951134.432151.41
Case 2217.62636.731084.382150.03
Case 3632.541821.253551.146300.08
Case 41281.814242.467700.5413696.18
Case 54806.9516343.0429559.4346918.13
Case 64474.0415394.9326954.4851871.79
Case 714504.9591493.11212042.83503089.38