Study On Rheological Behavior Of Deep Buried Composite Rock And Its Influencing Mechanism On TBM Jamming Disaster

The adaptability of the TBM technique in the complicated geology region is bad,and TBM shield jamming disaster frequently occurs easily when TBM tunneling through fault fracture zone,water-rich fissure zone and weak intercalated layer in composite ground,it would be necessary to study the disaster-causing mechanism of TBM shield jamming as well as control measures when TBM tunneling deep buried composite ground.In this paper,laboratory tests,theoretical analysis and numerical calculation method are combined,the rheology property and triaxial compression characteristic of composite rock specimens are analyzed,mechanical models which can characterize multiaxial behavior of composite rock are proposed,and the evolution of convergence deformation surrounding a TBM excavation tunnel in time and space are analyzed,as well.With the support of the ABH project,measures to control TBM shield jamming disaster when TBM tunneling in composite ground are proposed.The main research content and results are as follows:(1)Soft and hard rock-like material are made up with cement,quartz sand,water and other material,as well as standard composite rock-like specimens with different layer angles.A series of triaxial compression creep test of composite specimens were conducted in this paper,based on the test results,the influence of layer angle on the creep failure strength,failure mode,creep deformation and long-term strength of composite rock were analyzed.(2)Based on the traditional Mohr-Coulomb criterion and Burgers creep model,a damage softening model and a damage creep model were proposed by introducing the evolution law of accumulative damage,which can well describe the instantaneous deformation and creep properties of rock.The constitutive models were developed and used in the numerical calculation,and the comparison between the numerical calculation results and test results indicates that these models can effectively predicate the deformation and damage characteristics of rock.(3)Based on the engineering research background of ABH TBM tunneling project,physical model test of tunnel stability and deformation in composite ground was undertaken,the convergence deformation and failure characteristics of the surrounding rock masses were analyzed,as well as the stress and strain distribution inside the physical model with constant boundary loads,the results indicates that the failure and deformation of tunnel surrounding rock is mainly influenced by the stress conditions and lithologic character.(4)The deformation and failure characteristic of tunneling surrounding rock in composite ground have been analyzed by numerical simulation,the influence of layer angle,layer space,supporting force and excavation exposure time on the deformation and failure characteristic of tunneling surrounding rock have been explored.(5)By analyzing the cases of TBM shield jamming disaster,measures for preventing and relief the TBM shield jamming disaster were summarized,with the support of ABH project with TBM tunneling as well as the damage model proposed in this paper,the interaction between TBM machine and surrounding rock during the TBM machine tunneling through a fault fracture zone had been studied by numerical simulation,and the influence of overcut length and downtime on the friction force of TBM machine was explored,the research results could help to ensure the TBM tunneling through this area safely,efficiently and quickly.