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掌子面岩体节理特征和支护受力行为是隧道修建过程中的关键问题。该文以贵州松河隧道为依托,现场量测泥质粉砂岩产状,并建立离散元数值力学模型,研究泥质粉砂岩大断面隧道变形特性、力学响应。依据赤平投影,得到岩体优势节理面(组数及倾向、倾角)。裂隙岩体失稳由节理面剪切破坏引起,锚杆设置可有效地改善围岩受力特征,避免拱部岩体沿竖向节理面发生整体下滑破坏。初期支护轴力主要集中在边墙,锚杆对于初期支护起到“减压”作用。建议拱部60°范围内锚杆参数不变,减小边墙锚杆长度,可加快施工进度,提高整体稳定性。
The characteristics of facet rock mass joints and supporting forces are the key issues in tunnel construction. Based on the Songhe Tunnel in Guizhou Province, the authors took measurements of the occurrence of argillaceous siltstone on site and established discrete element numerical mechanical model to study the deformation and mechanical response of the large section of argillaceous siltstone. Based on the stereoprojection, the dominant joints of the rock mass (number of groups and their inclination and inclination) are obtained. The instability of the fractured rock mass is caused by the shear failure of the joint surface. The anchor bolt arrangement can effectively improve the stress characteristics of the surrounding rock and avoid the overall sliding failure of the arch rock mass along the vertical joint surface. The initial support shaft force is mainly concentrated in the side wall, anchor for the initial support play “decompression ” role. It is suggested that the parameters of anchor rods within 60 ° of the arch should not change, and the length of anchor rods on the side wall should be reduced to speed up the construction progress and improve the overall stability.