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

Table 1

Stratum parameters.

Strata	Elastic modulus (GPa)	Poisson’s ratio	Tensile strength (MPa)	Cohesion (MPa)	Internal friction angle (°)	Density (Kg/m^3)
Plain fill	0.3	0.27	0.025	0.25	28	1950
Moderately weathered granite	0.6	0.25	0.05	0.5	31	2050
Lumpy granite	5	0.20	2	2	42	2200
Slightly weathered granite	25	0.17	10	10	55	2300