中文摘要：

事先确定地下洞室开挖的安全预警指标以便及时采取工程措施，是确保围岩稳定的关键．根据洞室所在区域的工程地质资料建立地下洞室开挖的有限元模型，通过非线性分析，获得不同地质地段洞室断面的位移发展曲线，结合相关规范对围岩变形容许值的规定，以容易量测的洞室周边位移为对象，确定了地下洞室开挖的安全预警指标．最后，建立了一个圆形地下洞室数值模型，求解了4组围岩状态下地下洞室的安全预警指标，并与围岩塑性区发展情况对比，说明了利用数值模拟方法结合相关规范确定地下洞室施工安全预警指标可以用于判断洞室安全程度，也验证了地下洞室施工安全预警指标确定方法的可行性．

英文摘要：

For the sake of security during the process of excavating an underground grotto, the early safety warning indexes of the underground grotto are defined in advance and treatments are made as soon as possible, which is a key to ensure the stability of the surrounding rock. A numerical model is created based on the geological data, and the displacement curves of different sections can be obtained by FEM. With some technical codes of maximum displacement of the surrounding rock, the early safety warning indexes of the underground grotto can be confirmed by the displacement which can be measured easily. At last, a circular underground grotto is created using four different groups of geological data, and the early safety warning indexes of the underground grotto are solved by this method. Compared with the plastic zones of the surrounding rock, the early safety warning indexes which can be defined by the numerical method and some technical codes can be used to judge whether the underground grotto can be saved or not. The method of the early safety warning indexes of the underground grotto is feasible.