Risk Assessment of Shield Tunnel Construction in Karst Strata Based on Fuzzy Analytic Hierarchy Process and Cloud Model

Table 5

Weights of risk assessment indices.

First-level assessment indices	Weights	Second-level assessment indices	Weights
Karst geological conditions	0.287	Karst distribution characteristics	0.184
		Degree of karst development	0.248
		Scale of cave development	0.201
		Stability of the cave roof	0.206
		Cave filling situation	0.161
Hydrogeological conditions	0.176	Groundwater level	0.451
		Underground water richness	0.318
		Seasonal distribution of rainfall	0.231
Tunnel design	0.236	Shield tunnel length	0.195
		Tunnel buried depth	0.296
		Ratio of tunnel burial depth to shield diameter	0.311
		Maximum slope of tunnel	0.198
Shield construction	0.301	Tunnel support	0.233
		Distance of shield tunneling test	0.154
		Shield tunneling speed	0.184
		Grouting pressure	0.197
		Distance of shield deviation from design axis	0.232