断层破碎带地质特征对隧道围岩稳定性的影响研究

Study on the Influence of Geological Characteristics of Fault Fracture Zone on Stability of Tunnel Surrounding Rock

为了研究断层破碎带特征对隧道围岩稳定性的影响问题,依托某铁路隧道项目,以断层破碎带隧道围岩为研究对象,利用数值模拟软件Midas·GTS,通过控制变量法建立了隧道穿越不同地质特征的断层破碎带数值计算模型并进行计算分析,其中地质特征主要包括:断层围岩劣化程度、断层厚度、断层倾角以及断层走向线,数值模型适用于隧道开敞式TBM(Tunnel Boring Machine)施工。结果表明:在仅考虑隧道开敞式TBM施工影响,不考虑地层初始位移的情况下,断层破碎带隧道围岩劣化严重和断层破碎带厚度增加均会对隧道围岩稳定性产生不利影响;倾角60°的断层破碎带对隧道影响范围较大,隧道围岩稳定性差;断层破碎带走向线与隧道轴线夹角对隧道拱顶沉降的大小基本没有影响。

In order to study the influence of the characteristics of the fault fracture zone on the stability of the tunnel surrounding rock,this paper relies on a railway tunnel project,takes the fault fracture zone tunnel surrounding rock as the research object,and uses the numerical simulation software Midas·GTS to establish the tunnel crossing through the control variable method.Numerical calculation models of fault fracture zones with different geological characteristics are calculated and analyzed.The geological characteristics mainly include:deterioration degree of fault surrounding rock,fault thickness,fault dip and fault strike line.The numerical model is suitable for open TBM(Tunnel Boring Machine)construction.The results show that when only considering the impact of the open TBM construction of the tunnel and not considering the initial displacement of the formation,the serious deterioration of the tunnel surrounding rock in the fault fracture zone and the increase in the thickness of the fault fracture zone will adversely affect the stability of the tunnel surrounding rock;The fault fracture zone of 60°has a large influence on the tunnel,and the stability of the tunnel surrounding rock is poor;the angle between the strike line of the fault fracture zone and the tunnel axis basically has no effect on the settlement of the tunnel vault.