Mathematical Problems in Engineering / 2014 / Article / Tab 1

Research Article

Study and Application on Stability Classification of Tunnel Surrounding Rock Based on Uncertainty Measure Theory

Table 1

Evaluation factors and grading standard.

FactorsStability grade
Relative stability
General stability
Very instability

(1) Rock quality designation (RQD)/%>9075–9050–7525–50<25
(2) Rock uniaxial compressive strength/MPa>12060–12030–6015–30<15
(3) Rock mass integrity coefficient>0.750.45–0.750.3–0.450.2-0.3<0.2
(4) Strength coefficient of structural face>0.80.6–0.80.4–0.60.2–0.4<0.2
(5) Groundwater seepage (L/min·10 m)<55–1010–2525–125>125