Experimental Study of the Influence of Excavation Surface Stability and Sand Flowability Caused by Dense Slurry–Earth Pressure Balance Shield Tunneling in Silty Sand Stratum

Table 3

Geotechnical parameters of the in situ soil.

Soil layer name	γsat (kN/m^3)	e	c (kPa)	φ (°)	k (cm/s)
①1Backfill	19.1	0.810	13.2	15.6	N/A
③1Clay	20.0	0.720	58.6	17.4	2.90 × 10^−7
③2Silty clay	19.3	0.824	29.6	17.8	1.40 × 10^−5
④1Clayey silt	19.2	0.808	10.5	30.8	3.20 × 10^−4
④2Silty sand	19.2	0.802	5.7	32.4	3.52 × 10^−3
⑤1Silty clay	19.3	0.833	25.1	16.1	4.60 × 10^−6
⑥1Clay	20.3	0.670	60.1	17.8	6.30 × 10^−7

Note: N/A = not available, γ_sat is the saturated unit weight; e is the void ratio; c and φ are the effective cohesion force and the friction angle type, respectively; and k is the permeability.