软弱破碎围岩隧道大变形施工力学行为及支护对策研究

Study of large deformation construction mechanical behavior and support measures of soft rock in a deep buried extra long tunnel

围岩大变形是一种常见的、危害极大的施工地质灾害,为了减弱乃至消除此类灾害对工程的影响,首先,基于工程地质条件和地应力测试结果分析,揭示了典型地段软岩挤压大变形的成因;其次,采用有限差分程序研究了软岩段施工过程中围岩的受力和变形特征,分析了支护结构对围岩稳定性的影响,考虑支护有效抑制了围岩变形,将开挖造成围岩变形的影响范围由2倍洞径减至1倍洞径,较好地稳固了掌子面的挤压变形;最后,根据考虑支护的施工过程模拟结果分析,提出了该段软岩大变形控制措施及其变形过大造成侵限的具体处理对策,经开挖后监测数据验证,措施有效,确保了软弱破碎围岩隧道的顺利施工,对类似工程具有一定的借鉴意义。

Large deformation of surrounding rock is a common construction geological disaster of great harm.Some studies were done to abate or even eliminate the influence to the engineering.First,the cause of extrusion large deformation of soft rock in a typical section was revealed based on engineering geological conditions and stress test results analysis.Then,combined with field monitoring data,stress and deformation characteristics of the rock mass were studied by a finite difference program in a soft rock section construction process.The effect of supporting structure on the surrounding rock stability was analyzed.Surrounding rock deformation was effectively controlled by considering support,and the influence scope caused by excavation decreased from two times as much as the tunnel diameter to one time.Extrusion deformation of the working face was effectively controlled.According to the analysis of a construction process simulation considering support,control measures were presented to control the soft rock large deformation in this section,and specific treatments were proposed to deal with the intrude limit caused by large deformation.Good effects were gained by these measures,and it has reference meaning to similar engineering.