Study on Antiseismic Effect of Different Thicknesses of Shock Absorption Layer on Urban Shallow Buried Double Arch Rectangular Tunnel

Table 1

Calculation parameters.

Material name	Weight (N/m^3)	Poisson’s ratio	Modulus (Pa)	Friction angle (°)	Cohesion (Pa)
Surrounding rock	2.2 × 10^4	0.30	5 × 10^9	35.0	5 × 10^5
Bedrock	2.5 × 10^4	0.20	2 × 10^10	50.0	1.5 × 10^6
Tunnel lining	2.6 × 10^4	0.20	3.25 × 10^10	—	—
Cushion	2.4 × 10^4	0.20	2.25 × 10^10	—	—
Shock absorption layer	1 × 10^4	0.45	3 × 10^10	0.5	5 × 10^6
Silty clay	1.94 × 10^4	0.36	1.71 × 10^10	21.0	4.4 × 10^4