Force and Deformation Characteristics during the Reconstruction and Expansion of Shallow Single-Tube Tunnels into Large-Span Multiarch Tunnels

Table 6

Axial forces of initial supports of left and right tunnel tubes (kN).

Measurement point	FYY(A)	FYZ(B)	FZZ(C)	B/A(%)
Y/Z-1	−60.82	−102.10	−265.20	167.87
Y/Z-2	−51.66	−83.72	−82.26	162.05
Y/Z-3	−24.89	−42.12	−19.86	169.24
Y/Z-4	−10.07	−20.96	2.54	208.20
Y/Z-5	−9.87	−20.43	4.36	206.94
Y/Z-6	−21.15	−34.94	−7.53	165.18
Y/Z-7	−44.24	−63.46	−39.30	143.45
Y/Z-8	−81.42	−107.24	−89.41	131.71
Y/Z-9	−135.25	−167.34	−154.65	123.72
Y/Z-10	−196.93	−233.58	−219.30	118.61
Y/Z-11	−241.62	−277.99	−257.21	115.06
Y/Z-12	-201.11	−222.86	−226.12	110.82

Note. F_YY is the axial force of initial support of right tunnel tube after completion of right tunnel tube excavation. F_YZ is the axial force of initial support of right tunnel tube after completion of left tunnel tube excavation. F_ZZ is the axial force of initial support of left tunnel tube after completion of left tunnel tube excavation.