Three-Dimensional Nonlinear Seismic Response of Shield Tunnel Spatial End Structure

Table 5

Parameters of the concrete from the plasticity test.

Elastic modulus Ec (GPa)	Poisson’s ratio μ	Initial yield stress σco (MPa)	Compression strength σcu (MPa)	Tensile strength σtu (MPa)	Dilatation angle Ψ (°)	Eccentricity δ	fbo/fco	Kc	Viscosity coefficient u
36	0.2	33.27	47.57	3.88	38.0	0.1	1.16	2/3	0.0005

f_bo/f_co is the ratio of biaxial to uniaxial ultimate compressive strength; K_c is the ratio of biaxial to uniaxial ultimate compressive strength; and u is the ratio of the second stress invariant on the tensile and compressive meridian planes.