Research Article

Mechanical Behavior of the Special Segment Structure during Upward Shield Tunnel Construction

Table 2

Calculated values of internal forces at the top and bottom of the segment ring at the opening.

NumberLoad pairInternal force calculation value
M/(kN·m)N/(kN)

1Self-weight and foundation reaction force MA21 = 69.0,
MB21 = 99.5
MC21 = MD21 = −88.7
NA21 = −5.0,
NB21 = 8.6
NC21 = ND21 = 83.4

2Vertical soil pressure q1 and foundation reaction force p1MA22 = 668.7,
MB22 = 772.2
MC22 = MD22 = −772.2
NA22 = 48.7, NB22 = 0
NC22 = ND22 = 726.8

3Vertical opening soil unloading q2 and foundation reaction force p2 caused by excavationMA23 = −54.7,
MB23 = −63.2
MC23 = MD23 = 63.2
NA23 = −4.0,NB23 = 0
NC23 = ND23 = −59.5

4Lifting reaction force P and foundation reaction force ppMA24 = 3.6,
MB24 = 85.9
MC24 = MD24 = 137.1
NA24 = 1.7,NB24 = 0
NC24 = ND24 = −129

5Triangular distribution lateral soil pressure q3MA25 = −165.6,
MB25 = −258.2
MC25 = MD25 = 182.3
NA25 = 15.9, NB25 = 161.3
NC25 = ND25 = 0

6Uniform lateral soil pressure q4MA26 = −410.9,
MB26 = −474.6
MC26 = MD26 = 391.0
NA26 = 47.5,NB26 = 251.6
NC26 = ND26 = 0

7Stratum resistance qrMA27 = −164.7,
MB27 = −183.2
MC27 = MD27 = 191.9
NA27 = 70.2,NB27 = 72.2
NC27 = ND27 = 0

SumMA2 = −54.6,
MB2 = −21.6
MC2 = MD2 = 104.6
NA2 = 175.0, NB2 = 493.7
NC2 = ND2 = 621.7