Finite Element Analysis of Natural Thawing Heat Transfer of Artificial Frozen Soil in Shield-Driven Tunnelling

Table 2

Geotechnical parameters for different soil layers.

Soil layers	Moisture content (%)	Dry unit weight (kN/m^3)	Liquid limit (%)	Plastic limit (%)	Plasticity index	Liquidity index
Filled soil	29.6	14.4	31.5	19.7	11.8	0.84
Silty clay	25.7–37.6	13.1–15.5	31.6–47.2	18.3–26.6	12.3–20.6	0.38–0.89
Mucky silty clay	32.2–49.1	10.3–14.0	31.4–49.4	17.3–29.6	11.8–19.8	0.83–1.41
Silty sand	20.5–35.6	13.3–16.8	—	—	—	—