A Study on Excavation Characteristics of Tunnel with Upper-Soft Lower-Hard Stratum

Table 1

Basic physical and mechanical parameters for the upper “soft” formation.

Physical and hydraulic property index											Natural quick shear		Coefficient of compressibility	Modulus of compressibility	Coefficient of consolidation	Osmotic coefficient
Natural density	Grain density	Natural moisture content	Natural void ratio	Porosity	Liquid limit (10 mm)	Plastic limit	Plasticity index	Liquidity index	Dry density	Free swell ratio	Cohesion	Internal friction angle		Es ()		Kv
						Wp				Fs			(100~200) kPa
(g/cm^3)	(g/cm^3)	(%)		(%)	(%)	(%)			(g/cm^3)	(%)	(kPa)	(°)	MPa^-1	MPa
1.92	2.74	32.5	0.891	47.1	55.8	26.3	29.5	0.2	1.45	41	34.0	16.3	0.47	2.93	2.939	7.481