Shield Tunneling under Railway Station Throats in Soft Soil Areas: A Case Study

Table 1

Soil parameters of the construction site.

Layer index	Geologic origin	Classification	Buried depth (m)	Density, ρ(g/cm^3)	Permeability, vertical, (cm/s)	Permeability, horizontal, KH (cm/s)	Compression modulus, Es0.1-0.2 (MPa)	Cohesion, c (kPa) (CU test)	Friction angle, φ (°) (CU test)	Basic bearing capacity, fak (kPa)
11	Q4^3	Miscellaneous fill	1.2–6.2	–	–	–		–	–	–
11-2	Q4^3	Plain fill	0	–	–	–		–	–	–
21	Q4^3	Silty clay	0.5–3.0	1.79	8.9E − 07	1.33E − 06	4.56	18	16.5	70
3	Q4^2	Soft silty clay	5.1–9.3	1.69	2.22E − 07	3.2E − 07	3.17	13	13.5	50
41	Q4^2	Silty clay	11.4–17.4	1.66	1.95E − 07	2.75E − 07	2.07	13	11.5	50
51	Q4^1	Clay	14.5–25.4	1.75	2.62E − 07	1.9E − 07	3.02	14	17.5	70
51-1	Q4^1	Sandy silt	18.3–21.5	1.75	2.62E − 07	1.9E − 07	9.61	4	31	120
51-2	Q4^1	Silty clay	20.9–25.5	1.78	1.63E − 06	2.39E − 06	3.37	15	16	80
52	Q4^1	Silty sand	17.1–21.8	1.81	1.13E − 05	1.76E − 05	8.89	0	33.5	130
53-1	Q4^1	Silty clay	26–29.8	1.79	1.7E − 06	2.72E − 06	4.35	21	19	100
6	Q3^2	Clay	19.2–30.9	1.92	2.88E − 07	4.32E − 07	6.82	45	16.5	130
71	Q3^2	Sandy silt	26.7–34.9	1.90	3.2E − 04	4.37E − 04	11.41	10	31.3	150