Research Article
Risk Control Technology for Water Inrush during the Construction of Deep, Long Tunnels
Table 1
Risk classification of root node variables.
| | Number | Variables | Risk levels | | I | II | III | IV |
| | Karst cave size (karst cave radius/tunnel radius) | <1 (small) | 1∼3 (medium) | 3∼6 (large) | >6 (super large) | | Relative distance between karst cave and fault zone | >30 m (far away) | 30∼20 m (far) | 20∼5 m (nearer) | <5 m (very nearer) | | Completeness of surrounding rock | >75% (intact surrounding rock) | 75%∼50% (relatively complete surrounding rock) | 50%∼25% (fractured surrounding rock) | <25% (extremely fractured surrounding rock) | | Strength of rock mass | >60 MPa (very hard rock) | 60∼35 MPa (hard rock) | 35∼15 MPa (soft rock) | <15 MPa (very soft rock) | | Water pressure ((tunnel depth + tunnel height)/groundwater depth) | <5 (low, extremely low) | 5∼15 (relatively low) | 15∼25 (relatively high) | >25 (high, extremely low) | | Water inflow (seepage of 5 m long tunnel) | <90 m3/h | 90∼180 m3/h | 180∼360 m3/h | >360 m3/h | | Relative distance between karst cave and palm surface | >150 m (far away) | 150∼80 m (far) | 70∼30 (nearer) | <30 m (very near) | | Rationality of construction organisation process | Reasonable | Relatively reasonable | Relatively unreasonable | Unreasonable | | Adequacy of construction scheme | Scientific | Relatively scientific | Relatively unscientific | Unscientific | | Normative nature of education and training | Regular | Relatively regular | Relatively irregular | Irregular | | Implementation of design scheme | Good implementation | Relatively good implementation | Relatively poor implementation | Poor implementation | | Blasting excavation quality | Good | Relatively good | Relatively poor | Poor | | Support level | High support level | Relatively high support level | Relatively poor support level | Poor support level | | Monitoring measurement quality | Good quality | Relatively good quality | Relatively poor quality | Poor quality |
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