Characteristics of Karst Cave Development in Urban Karst Area and Its Effect on the Stability of Subway Tunnel Construction

Table 1

Mechanical parameters of geotechnical materials in the model.

Materials	Gravity (kN/m^3)	Elastic modulus E (MPa)	Poisson’s ratio	Cohesion c (kPa)	Internal friction angle φ (°)
Fill	20	10	0.3	8	20
Clay	25	15	0.3	14	10
Moderately weathered limestone	25	100	0.3	100	30
Concrete segment	25.4	34500	0.3	/	/