Ground Settlement of High-Permeability Sand Layer Induced by Shield Tunneling: A Case Study under the Guidance of DBN

Table 1

Physical properties of soil layers.

Soil layer number	Soil layer name	Natural moisture content (%)	Natural density (g/cm^3)	Void ratio	Poisson’s ratio	Cohesion (kPa)	Internal friction angle (°)	Characteristic value of bearing capacity of foundation soil (kPa)	Permeability coefficient (cm^-6/s)
									Horizontal	Vertical
1-2	Plain fill	—	1.8	—	—	—	—	—	—	—
2-1	Silty clay	32.14	1.83	0.97	0.35	16.90	7.82	100	7.6	8.9
2-3	Fine sand	16.45	2.00	0.56	0.30	3.5	24.93	140	—	8246.2
2-4	Coarse sand	11.12	2.09	0.42	0.30	0	32.0	290	—	31925.0
2-4-1	Silty clay	29.66	1.92	0.83	0.35	38.56	12.00	135	15.6	8.4
7-1	Silty clay	28.88	1.95	0.80	—	37.38	12.45	—	—	—
7-2	Coarse sand	10.53	2.08	0.42	0.35	0	35.39	150	13.6	16.2
7-3	Silty clay	27.83	1.97	0.78	0.30	37.38	12.45	300	—	24000