| In recent years,due to the extensive development of tunnel engineering in China,TBM has been more and more favored by engineering construction due to its outstanding advantages.During the construction of TBM tunneling,due to the complexity of geological conditions,the underground rock mass conditions have obvious influence on the rock breaking process of hob tunneling all the time.At the same time,the rock breaking effect of hob has a direct impact on the actual project schedule and cost.It is of great theoretical value to study the failure mechanism of rock mass and the evolution law of energy under the action of hob to improve the construction efficiency of engineering and relevant optimization and improvement of TBM.In this paper,digital image correlation technology and thermal imaging technology are used to carry out penetration rock-breaking test under the action of double hob for rock mass under different joint inclination conditions,and the microscopic crack propagation characteristics and macroscopic energy evolution rules of rock mass under the action of hob are deeply studied.At the same time,the discrete element software is used to simulate the hob rock breaking process under different geological conditions,and the results are compared with the test results,and the influence of joint spacing and confining pressure on the hob rock breaking effect is further explored.The main research contents are as follows:(1)using self-made hob and jointed rock mass specimens,and through the DIC and infrared thermography observation system,rock breaking tests of rock mass with different jointed dip Angle under the action of double hob were carried out.The crack propagation process on the surface of jointed rock mass under hob load was analyzed,and the effects of different joint inclinances on the crack propagation characteristics were studied,including the crack properties,temperature characteristics,propagation modes and propagation specific energies of different cracks.(2)based on the test results,the energy input and energy dissipation of rock mass are analyzed,and the load characteristics of hob rock breaking and the infrared radiation temperature characteristics of rock mass failure under different joint inclination Angle are studied.From the perspective of hob rock breaking energy utilization,the changes of hob rock breaking efficiency and energy utilization rate under different joint angles are studied,and the evolution law of hob rock breaking energy is revealed.(3)using the discrete element software to different joint conditions and rock mass under confining pressure to numerical simulation process of the invasion of the hob,analyzing damage characteristics of rock mass under hob and gear hob,etc.,the change rule of rock than to explore the influence of different rock mass conditions on the hob broken rock mechanism,prediction for construction for TBM engineering provides important reference value. |
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