考虑结构面产状的层状岩体引水隧洞围岩精细化评分探讨

Fine Scoring for Surrounding Rock of Water-Diversion Tunnel in Layered Rock Mass Considering Occurrence of Structural Plane

为了解层状岩体结构面产状对围岩评分的影响,在总结国内外相关规范及研究成果的基础上,综合考虑围岩结构面产状分布,对层状岩体引水隧洞围岩评分进行精细化分析,重点考虑隧洞开挖方向和岩体结构面倾向、倾角对隧洞围岩稳定性的影响。首先,采用有限元软件Midas GTS对21种工况进行数值模拟,对模型拱顶、边墙、底板处的位移、围岩压力、最大剪应力、最大主应力和最小主应力计算结果进行综合分析;然后,采用层次分析法(AHP)进行指标权重计算;最后,运用隶属度函数对各指标构建模糊矩阵,用得出的模糊矩阵乘以AHP法所得权重,得出结构面产状评分结果。研究表明:当结构面走向与开挖方向夹角为0°时,随着结构面倾角的增加,拱顶和底板评分大幅增加。

To investigate the influence of occurrence of layered rock mass on the surrounding rock scroing,relevant specifications and research results in China and abroad are summarized,fine scroing is conducted on the surrounding rock of water-diversion tunnels in layered rock mass considering the structural occurrence distribution of surrounding rocks,and the influence of tunnel excavation direction,the inclination and dip angle of the rock structural plane on the stability of the surrounding rock of the tunnel are analyzed.First,the finite element software Midas GTS is used to simulate 21 working conditions,and the displacement,surrounding rock pressure,maximum shear stress,maximum and minimum principal stresses at the crown,sidewall and bottom plate of the model are comprehensively analyzed.Second,the membership function is used to construct a fuzzy matrix for each index,and the fuzzy matrix obtained is multiplied by the weight obtained by AHP method to output a more precise evaluation result of structural plane occurrence.The results show that when the angle between the structural plane and the excavation direction of the tunnel is 0°,the scores of crown and bottom plate increase greatly with the increase of the dip angle of the rock mass.