岩质隧道围岩稳定分析与分级研讨

On Stability Analysis and Classification of Surrounding Rocks in Rock Tunnels

1975年后有限元数值极限方法的出现和计算机的应用和发展,使得工程材料的弹塑性解析计算进入到数值极限计算的新时代。文章所研究的岩质隧道就是采用了这一新方法,即强度折减法与荷载增量法,以及最近提出的极限应变法。为解决岩体隧道围岩力学参数的不确定性,提供较为科学合理的围岩力学参数,必须做好理论、勘察和经验相结合的围岩分级工作。以轨道交通隧道围岩分级为例提升分级的水准,包括强度指标的改进,以定量分级为主的分级方法,合理确定岩体基本质量指标BQ值,增加围岩分级数量,制定区间隧道与车站隧道的围岩分级表,定性与定量分级方法的协调与统一。最后,确定围岩自稳能力量化指标,通过反算提出较为科学合理的围岩物理力学参数。

After 1975, the appearance of finite element numerical limit method and the application and development of computer technology have brought the elastic-plastic analytical calculation of engineering materials into a new era of numerical limit calculation. The new methods, namely, strength reduction method and load increment method,as well as the recently proposed ultimate strain method, are adopted in the rock tunnels studied in this paper. To solve the uncertainty of mechanical parameters of surrounding rock in rock tunnels and provide more scientific and reasonable mechanical parameters of surrounding rock, the surrounding rock classification must be made combining theory, investigation and experience. Taking the surrounding rock classification in rail transit tunnels as an example,the improvement of the classification level includes improving the strength index, mainly adopting the quantitative classification method, reasonably determining the basic index BQ value of rock mass quality, increasing the number of surrounding rock classifications, formulating the surrounding rock classification tables for the running tunnel and the station tunnel, and achieving the coordination and unification of qualitative and quantitative classification methods. Finally, the quantitative indexes of surrounding rock self-stability are determined, and the more scientific and reasonable physical and mechanical parameters of surrounding rocks are put forward through back calculation.