Table 4 Stratum redefinition results of the tunnel project from Qian-Zhuang to Ke-Ning Road.

From: A multistage model for rapid identification of geological features in shield tunnelling

Redefined stratum

Ordinary stratum number

Ordinary stratum name

1

K2c-2

Strong-weathered argillaceous siltstone

K2c-3

Medium-weathered argillaceous siltstone

2

â‘¡-1c-d2-3

Sandy silt

â‘¡-2c-d2-3

Sandy silt

â‘¢-2c-d2-3

Sandy silt

â‘¢-3d-c1-2

Sandy silt

â‘¢-4e

Sandy gravel soil

3

â‘¡-1b2-3

Silty clay

â‘¡-2b4

Muddy silty clay

â‘¡-3b2-3

Silty clay

â‘¢-2b2-3

Silty clay

â‘¢-3b1-2

Silty clay

â‘¢-1b1-2

Silty clay