岩溶区公路隧道施工围岩分级指标体系研究

Research on classification index system of surrounding rocks for highway tunnel construction in karst areas

岩溶在我国分布广泛,公路隧道勘察设计阶段的围岩分级准确度往往不能满足施工要求;而这点在岩溶区公路隧道表现尤为突出。为解决这个问题,通过对国内外常用围岩分级方法的指标和公路隧道施工现场常用围岩分级指标的统计分析,获得岩溶围岩分级共性指标;通过对南方岩溶区域地质特征分析,提出岩溶围岩分级特殊性指标,最终获得以岩溶围岩分级共性指标和特殊性指标(岩溶发育对隧道影响程度——与岩溶发育程度、水、溶洞充填物、溶洞规模及分布方位有关)为基础的岩溶围岩分级指标体系,然后利用规范定性定量法和打分制法获取各围岩分级指标参数。并在此基础上,利用围岩分级指标缩减试验验证南方岩溶围岩分级指标体系的可靠性和合理性,并将其应用于天生桥隧道和关上二号隧道进行围岩分级,准确率达93.3%。

Karst distributes widely in China. The accuracy of surrounding rock classification of high- way tunnel in survey and design stage fails to meet the requirements of construction, which is partic- ularly prominent in karst area. In order to solve the problem, through the statistical analysis of the common surrounding rock classification indexes in domestic and abroad highway tunnel construc- tions, a general index of karst surrounding rock classification was obtained and the particularity of karst surrounding rock was analyzed to obtain a special index of surrounding rock classification in karst area. The final surrounding rock classification index system in karst area was obtained based on the general index and the special index （ the influence of karst development on tunnel--the degree of karst development, water, karst filling material, cave size and cave distribution）. The validation of surrounding rock classification index system was tested by applying to Tianshengqiao tunnel and Guanshang tunnel No. 2 and the accuracy was 93.3%.