深埋炭质板岩隧道的大变形分级研究

为合理实现炭质板岩隧道的大变形分级，以木寨岭隧道大变形段五个监测断面的监测成果为基础，利用极限位移准则实现其现状分级，利用递进优化思路构建隧道大变形预测模型，并根据外推预测结果的速率均值实现大变形发展趋势分级。结合隧道大变形的现状分级和发展趋势分级结果，开展隧道大变形发育程度的综合评价。实例分析表明：在大变形现状分级过程中，不同位置处的大变形等级存在一定差异，其中，以DK180+960 m断面的大变形程度相对最为严重，属Ⅴ级-极严重，其余四个断面的大变形等级为Ⅳ级-严重；通过发展趋势分级，得DK180+940 m断面和DK180+960 m断面的大变形发展趋势等级为2级，其余三个监测断面属1级，均具持续增加趋势，趋于不利方向发展。结合前述大变形现状分级和发展趋势分级结果，综合得出DK180+960 m断面的大变形最为不利，其次是DK180+940 m断面，其余三个断面的大变形程度相似。因此，可根据断面的大变形综合评价结论来制定具有针对性的防治措施，以达到优化现场防治措施的目的。

Study on large deformation classification of deep buried carbonaceous slate tunnel

In order to reasonably realize the large deformation classification of carbonaceous slate tunnel, this work utilized the limit displacement criterion to classify the present situation of the Muzhailing tunnel based on monitoring results of five monitoring sections in large deformation section. A prediction model of large deformation for the tunnel was constructed by using the idea of progressive optimization, and the development trend classification of large deformation was realized according to the average rate of extrapolation prediction. In combination with the classification of the current situation and development trend of large deformation, a comprehensive evaluation of the development degree of tunnel large deformation was conducted. The case analysis shows that, in the process of large deformation classification, there are some differences in the large deformation grades at different positions, among which the large deformation of section DK180 + 960 m is relatively the most significant, belonging to grade V - extremely serious, and the large deformation grade of the other four sections is grade IV - serious. The development trend classification indicates that, the development trend of large deformation of section DK180 + 940 m and section DK180 + 960 m is classified as Level 2, and the other three monitoring sections are Level 1, all of which have a continuous increasing trend and tend to develop in an unfavorable direction. Combined with the above classification results of large deformation status and development trend, the large deformation of section DK180 + 960 m is inferred to be the most unfavorable, followed by section DK180 + 940 m, and the large deformation degree of the other three sections is similar. Therefore, targeted prevention measures can be formulated according to the comprehensive evaluation conclusion of large deformation of the section, so as to optimize the on-site prevention measures.