Investigation of Quantitative Evaluation Method and Engineering Application of Shallow Buried Tunnel Face Stability

The stability of a tunnel face and the rationality its supporting structures are guarantees for safe construction. This paper established quantitative analysis model stability, obtained calculation formula coefficient based on silo theory surrounding rock, then realized description under condition pipe roofing support, bolting grouting support reserved core soil. Finally, discrimination optimization system was developed, effects were quantitatively evaluated, measures optimized buried Chongqing rail transit passing through suburban expressway. results show that increased by 103~412%, effect is most significant. reinforcement with soil has lowest cost. carries out rapid judgment provides evaluation method assessment face. On-site monitoring indicates cumulative displacement gradually time; farther from surface, smaller displacement. reached 34.50 mm before scheme. scheme + led to gradual convergence final surface settlement reduced 15.50 mm, which about 44.93% scheme, ensuring construction tunnel. research certain theoretical significance shallow tunnels.