Numerical Simulation Research on the Stability of Urban Underground Interchange Tunnel Group

Table 2

Stress concentration of tunnel in characteristic area.

The serial number	Type	Vertical stress concentration value (MPa)	Length (m)	The lithology
1	Qiaocheng gap—K3 + 100-320	4∼6	30	Breezy granite
2	Qiaocheng gradient section—K3 + 100-500	9∼12	134	Medium weathering/block weathering/breezy
3	Qiaocheng-Baopeng joint construction section—K3 + 580-920	8∼10	448	The weathering
4	Qiaocheng left line gap—K3 + 860-K4 + 50	5.2∼7.4	72.9	Moderate weathering/breezing
5	Qiaocheng right line and Baopeng ramp interchange—K0 + 840-K1 + 20	10.5∼22.3	9.9	Moderate weathering/breezing
6	Baopeng right line gap—K18 + 580-780	1.8∼2.4	536	Moderate weathering
7	Baopeng right line gap—K19 + 120-920	4.9∼9.7	94.3	Moderate weathering/lump weathering/slight weathering
8	Baopeng right line gap—K19 + 320-580	1.9∼3.2	594	Plain fill