Geological Type Recognition by Machine Learning on In-Situ Data of EPB Tunnel Boring Machines

Table 3

Chi-square value and P-value of top 7 features in Tianjin Metro Line 9.

Name	Chi-square value	P-value
Accumulated rotation number of screw machine	4913.95	<1e − 275
Primary voltage of high-voltage transformer	4360.52	<1e − 275
Filling mud pressure no. 2	3692.76	<1e − 275
Initial pitch angle y	3626.04	<1e − 275
Upper control limit of soil discharge quantity	3339.61	<1e − 275
Standard deviation of soil discharge quantity	3311.44	<1e − 275
Target value of soil pressure	3162.43	4.23e − 275