Table 5 Normalized centrality of risk factors.

Poor awareness of p security (p1)

Insufficient professional skills (p2)

Poor safety emergency response ability (p3)

Inadequate p protection (p4)

Poor physical or mental health (p5)

Violation of operating regulations (p6)

Inadequate equipment maintenance (w1)

Equipment failure (w2)

Unreasonable equipment selection (w3)

Unreasonable arrangement of mechanical work (w4)

Improper construction material storage (w5)

Defective retaining structure (w6)

Insufficient strength and stability of internal support (w7)

Substandard strength of anchor rod and pull rod (w8)

Unqualified construction materials (w9)

Inadequate safety education and training (m1)

Incomplete rules and regulations (m2)

Insufficient safety investment (m3)

Inadequate safety supervision and hidden danger inspection (m4)

Inadequate security disclosure (m5)

Illegal subcontracting (m6)

Unreasonable safety construction organization design (m7)

Poor engineering geological and hydrological conditions (e1)

Harsh weather or natural disasters (e2)

Complicated underground pipeline laying (e3)

Closing to large high-rise buildings (e4)

Complicated peripheral traffic (e5)

Harsh operating environment (e6)

Unspecified or deviation of geological and hydrological survey (t1)

Improper design scheme (t2)

Not prepared special construction scheme (t3)

over-excavation (t4)

Improper construction method of retaining structure (t5)

Error in setting and demolishing supports (t6)

Insufficient monitoring of foundation pit (t7)

Untimely dewatering and drainage (t8)