基于变形分级的挤压性围岩隧道变形计算方法研究

Research on Deformation Calculation Method of Squeezing Rock Tunnel Based on Deformation Classification

挤压性围岩隧道具有变形量大、变形速率高、变形持续时间长的显著特征,变形规律及变形预测研究可为变形控制提供理论支撑。采用数值方法确定了岩体强度应力比、支护抗力和支护封闭距离3个关键影响因子,提出了基于变形分级的挤压性围岩隧道变形计算方法。研究结果表明:①隧道相对变形随强度应力比的增大而减小,随支护抗力的增大而减小,随支护封闭距离的增大而增大;②所提出的变形计算方法,计算相对变形与现行挤压性围岩隧道变形分级标准中相对变形指标范围一致,表现出的变形规律与工程实践一致,验证了变形计算方法的合理性;③在同等围岩条件下,可通过提高支护刚度、缩短支护封闭距离实现控制隧道变形的目的。研究成果可为挤压性围岩隧道变形预测及变形控制提供理论支撑。

The squeezing rock tunnel has significant deformation characteristics such as large deformation,high deformation rate,and long deformation duration.Research on deformation law and deformation prediction can provide theoretical support for deformation control.Three key influencing factors of rock strength stress ratio,support resistance and support sealing distance were determined by numerical method,and a deformation calculation method based on deformation classification was proposed.The research results indicate that:①the relative deformation of the tunnel decreases when the strength-stress ratio increase.And the relative deformation of the tunnel decreases when the support resistance increase,and it increases when the enclosed distance of the support increase.②The results show that the relative deformation calculated by the proposed method is consistent with the range of relative deformation index in the current classification standard of tunnel deformation in squeezing surrounding rock.And the deformation law is consistent with the engineering practice,which verifies the rationality of the deformation calculation method.③Under the same surrounding rock conditions,the purpose of controlling tunnel deformation can be achieved by improving the support stiffness and shortening the support sealing distance.The research results can provide theoretical support for deformation prediction and deformation control of squeezing surrounding rock tunnels.