隧道稳定性分析与设计方法讲座之二：隧道围岩稳定性分析及其判据

作为一个讲座对以往研究成果作一综述。分析隧道围岩稳定性的3种判据，提出有严格力学依据的稳定安全系数作为围岩稳定分析的定量判据。指出围岩有剪切安全系数与拉裂安全系数，并建议采用强度储备安全系数作为围岩稳定安全系数。建立土体隧道稳定分析的新理念和新方法，计算中考虑了围岩的荷载释放，初期支护作为弹塑性材料加固围岩，并应具有一定安全系数，以确保施工安全。二次衬砌作为弹性结构，围岩、初期支护与二次衬砌共同作用确保运行安全。对岩石围岩分级提出初步建议，并以无衬砌围岩安全系数作为各级围岩自稳能力的定量判据，由此反推出各级围岩的力学强度参数，改善了参数的合理性。

Analysis on and Criteria of Stability of Surrounding Rock of Tunnel

As a summary of the past research achievements, the paper analyses three criteria for the stability of surrounding rock of tunnels and puts forward that stability safety factor with strict mechanic basis can be taken as the quantitative criteria of the stability of surrounding rock. The paper states that the safety factor of surrounding rock has shear safety factor and tensile safety factor and suggests that the safety factor of strength reserve should be adopted as the safety factor of surrounding rock. New theory and new method of stability analysis of soil tunnel are established, and the load release of surrounding rock is taken into consideration in the calculation. The primary lining is seemed as elasto plastic material to reinforce the surrounding rock and the primary lining should have a certain safety factor to ensure the safety during tunnel construction. The secondary lining adopts elastic structure and ensures the safety of the tunnel in operation together with the combined action of surrounding rock and primary lining. The paper then provides a preliminary proposal for the classification of the surrounding rock and takes the safety factors without lining as the quantitative criteria of the self support capability of surrounding rock of each grade. In this way, the parameters of mechanic strength of surrounding rock of each grade are obtained through inverse method, which can improve the rationality of the parameters. 