岩石温度对盘形滚刀掘进参数破岩特性的影响

为了研究在岩石温度变化条件下盘形滚刀掘进参数对破岩特性的影响,以颗粒流理论为平台,从细观角度上建立了基于岩石温度变化的盘形滚刀热力学破岩数学模型,模拟了不同工况下岩石裂纹生成、扩展和岩渣形成的全过程,并对掘进参数对破岩特性的影响规律进行了研究,从细观角度解释了不同岩石温度下滚刀的破岩机制.利用直线式TBM滚刀破岩实验台,通过实验验证在岩石温度变化条件下掘进参数对滚刀破岩的影响规律是否与数值模拟有较好的一致性.研究结果表明:1)岩石温度升高,降低了岩石硬度、强度等力学性质,破岩时裂纹数增多且微裂纹迅速扩展,降低了滚刀破岩载荷,提高了破岩效率;2)低贯入度时,岩石不容易被侵入破碎;随着岩石温度的升高,岩石越来越容易挤压破裂;随着贯入度增加,失效区域进一步扩大,破岩效率提高;3)滚刀之间的协同作用随刀间距的增加而减弱,最优刀间距随岩石温度的升高而增加,随贯入度的增大而增加;4)提高岩石温度能增强滚刀之间的协同作用,提高破岩效率.

Influence of Different Rock Temperatures on Rock Breaking Characteristics of Disc Cutter Tunneling Parameters

In order to study the influence of different rock temperatures on the rock breaking characteristics of TBM disc cutter tunneling parameters, and on the basis of particle flow theory, the thermodynamic mathematical model of rock breaking by TBM disc cutter based on rock temperature changes was established from the microscopic view. The whole process of rock crack formation, crack propagation and rock slag formation was simulated. Then, the influence laws of different tunneling parameters on rock breaking characteristics were studied, which explained the rock breaking mechanism of TBM disc cutter under different rock temperatures from micro view. Finally, by using the linear experiment platform of rock breaking by TBM disc cutter, experimental verification was accomplished to find out whether the influence laws of rock breaking characteristics by TBM disc cutter tunneling parameters under different rock temperatures conditions were kept well with numerical simulation results. The research results show that: (1) the increase of rock temperature decreases some mechanical properties of rock such as hardness, strength and so on, which leads to the crack number increase and rapid expansion of micro crack when rock breaking rock, hence reducing the rock breaking load of TBM disc cutter and improving the rock breaking efficiency; (2) the higher the temperature, the lower the rock stress. The stress distribution obeys the Buzin Neske stress circle rules, where the stress value below the region of the cutting edge was the maximum and gradually decreases radiation around. The stress is basically symmetrical distribution and total rock stress becomes smaller as temperature increases; (3) when the penetration depth is low, the rock is not easy to be broken and intruded. With the increase of rock temperature, the rock is easier to be extruded and ruptured. With the increase of the penetration depth, the failure zone is further expanded, which improves the rock breaking efficiency; (4) the synergistic action between TBM disc cutters decreases with the increase of the cutter space, and the optimal cutter space increases with the increase of rock temperature and penetration depth; and (5) the synergistic action between TBM disc cutters can be enhanced by increasing rock temperature to improve the efficiency of rock breaking.