富水蚀变岩大断面高速铁路隧道开挖大变形控制技术

以富水花岗岩侵入蚀变带区域高速铁路隧道建设为背景,对隧道开挖围岩变形控制技术进行研究。运用隧道工程理论、数值模拟和现场监测等技术与方法,提出了从全断面开挖法、台阶法、CD法到CRD法的安全度逐渐增加的隧道开挖方法,确定了避免富水花岗蚀变岩进一步应变软化和力学参数弱化的隧道开挖支护结构形式及其参数,得出了适当加大预留变形量结合衬砌紧跟的施工工艺。实践表明,按研究出的开挖方法和支护方案进行施工,可以有效控制隧道围岩大变形而使变形快速收敛,能够减少侵限处理工作量,并确保富水花岗蚀变岩隧道开挖时围岩稳定和地下工程结构安全。

Control Technology of Large Deformation in Tunnel Excavation in Water-rich Contact Altered Rock on High Speed Railway

Taking the high-speed railways tunnel construction with water-rich rock intruding into alteration zone as background,this paper studied the control method for tunnel excavation rock-mass deformation.This paper put forward the tunnelling method with increasing safety degree from full section excavation,benching tunnelling method,CD tunnelling method and CRD tunnelling method by using the tunnel construction theory,numerical simulation and on-site monitoring technology,confirmed the forms and parameters of tunnel excavation support structures that can avoid water-rich rock strain softening and mechanical parameters weakening further,and concluded the construction technology of appropriate increasing reserved deformation with close-following lining.The practice shows that the methods of excavation and supporting scheme for construction that is introduced in this paper can effectively control the surrounding rock large deformation of tunnel and make them fast convergence,reduce the boundaries treatment workload of intrusion,and ensure the surrounding rock stability and underground engineering structure safety in the water-rich altered rock tunnel excavation.