崤山隧道软弱围岩台阶法施工预留变形量预测原理及变形控制技术

Prediction Principle of Reserved Deformation and Deformation Control Technology for Xiaoshan Tunnel Constructed by Bench Method in Soft Rock

为更加合理地设计隧道开挖预留沉降量,避免造成超挖过多增加衬砌混凝土量或初期支护侵限的问题,依据变位分配控制原理,采用数值模拟及现场监测数据分析等手段,分析软弱围岩台阶法施工时各工序施工对变形的影响程度,确定分步变形控制标准,根据分步变形控制标准建立相应的预警系统和应急工程措施,并依据分步实际变形量预测初期支护的最终变形量,为同一设计围岩等级下隧道预留变形量的动态设计提供指导。在崤山隧道台阶法施工工程中,成功地将初期支护变形控制在预留变形量之内,并动态设计下一循环预留变形量的大小,减少初期支护混凝土用量12.86%,可为隧道多步序开挖预留变形量的设计提供一定的借鉴意义。

In order to rationally and dynamically design the reserved deformation for tunnel excavation in soft and weak rock and avoid overbreak-induced lining concrete increase and clearance interfering of primary support, the influence of each construction procedure of bench method on tunnel defomlation is analyzed by numerical simulation and site monitoring, and the control standard for deformation of each construction procedure is determined based on deformation distribution principle. And then the corresponding early wanting systems and engineering countermeasures are established according to stepped deformation control standards; the final deformation of primary support can be predicted by site monitoring data of each construction procedure. The application results of the above-mentioned methods to Xiaoshan Tunnel constructed by bench method show that the primary support deformation is within reselved deformation, the reselved deformation of followed construction circle is dynamically designed, and the concrete amount for primary support has been reduced by 12.86%. The results can provide reference for reserved deformation designed of tunnel constructed by stepped method.