Influence of Underground Tunnel Excavation on Upper-level Existing Pipelines

Table 1

Subgrade coefficient values.

Condition	Subgrade coefficient	k1 (kN/m^3)	k2 (kN/m^3)	k3 (kN/m^3)
Subgrade coefficient value in excavation section	Calculated parameter 1	1.4 × 10^4	0.3k1	0.1k1
	Calculated parameter 2	1.4 × 10^4	0.3k1	0.05k1
	Calculated parameter 3	1.4 × 10^4	0.3k1	0.075k1
	Calculated parameter 4	1.4 × 10^4	0.3k1	0.125k1
	Calculated parameter 5	1.4 × 10^4	0.3k1	0.15k1
Subgrade coefficient value in excavation-affected section	Calculated parameter 1	1.4 × 10^4	0.3k1	0.1k1
	Calculated parameter 6	1.4 × 10^4	0.6k1	0.1k1
	Calculated parameter 7	1.4 × 10^4	0.5k1	0.1k1
	Calculated parameter 8	1.4 × 10^4	0.4k1	0.1k1
	Calculated parameter 9	1.4 × 10^4	0.2k1	0.1k1