基于节理精细化描述的隧道围岩变形破坏特征分析

CHARACTERISTICS ANALYSES OF DEFORMATION AND FAILURE ON TUNNEL SURROUNDING ROCK BASED ON FINE DESCRIPTION OF JOINTS

福州机场高速二期金鸡山隧道是国内首例双向八车道连拱隧道,隧道区域内节理发育,围岩破碎,隧道围岩稳定性受节理展布特征影响显著。通过对金鸡山隧道中导洞开挖掌子面、区段断面及其他出露区域节理的采集,利用统计分析方法对隧道正洞区域内的节理展布预测;在此基础上,利用非连续变形分析(DDA)法对金鸡山隧道围岩变形、破坏过程进行模拟计算,对隧道围岩变形、破坏的典型阶段进行划分,并指出隧道容易发生变形破坏的部位。最后,将DDA计算分析结果与隧道施工过程中发生的塌方进行比较,两者性态一致,表明DDA法在隧道围岩的稳定性分析基本能够反映隧道真实稳定性,在隧道围岩稳定性分析方面具有良好的应用前景。

Jinjishan tunnel in the second stage of Fuzhou airport expressway project is the first multi-arch tunnel with bidirectional eight-lane in China.There were developed joints and crushed rock in tunnel surrounding rock,and the characteristics of joint distribution had significant effect on the stability of tunnel surrounding rock.This paper collected the data of joints in several cross-sections of mid-drift and other outcrop areas of the tunnel,and predicted joints distribution of the main tunnel by using statistical analysis method.On the basis of this,the paper made simulation calculation for the deformation and failure process of the tunnel surrounding rock with the method of discontinuous deformation analysis（DDA）.Meanwhile,it divided the typical stages of the deformation and failure process for the tunnel,and also indicated the most possible damaged parts.At last,the paper made a comparison between the result of DDA calculation and practical collapse of Jinjishan tunnel,which were almost the same.Therefore,it is shown that the DDA method is capable of analyzing the stability;and it has good application prospect of stability analysis for tunnel surrounding rock.