This paper analyzed the characteristics of welding solidification crack of stainless steels,and clearly re- vealed the the of the deformation in the molten - the pool and the solidification shrinkage on the stress -...This paper analyzed the characteristics of welding solidification crack of stainless steels,and clearly re- vealed the the of the deformation in the molten - the pool and the solidification shrinkage on the stress - strain fields in the trail of molten - weld pool.Moreover, rheologic properties of the alloys in solid - liquid zone were also obtained by measuring the hading and unloading deform curves of the steels.As a result, a numerical model for simulation of stress - strain distributions of welding solidifi- cation crack was developed. On the basis of the model,the thesis simulated the driving force of solidifi- cation crack of stainless steels, that is, stress - strain fields in the trail of molten-weld pool with fi- nite element method.展开更多
刀盘作为全断面岩石隧道掘进机(Full Face Rock Tunnel Boring Machine,TBM)的直接开挖部件,承受刀具破岩的全部载荷,其强度可靠性是评价TBM刀盘性能的重要指标。受复杂地质条件及刀岩相互作用机制的影响,刀盘在掘进过程中承受的载荷具...刀盘作为全断面岩石隧道掘进机(Full Face Rock Tunnel Boring Machine,TBM)的直接开挖部件,承受刀具破岩的全部载荷,其强度可靠性是评价TBM刀盘性能的重要指标。受复杂地质条件及刀岩相互作用机制的影响,刀盘在掘进过程中承受的载荷具有很强的随机性,故在单一特定工况下研究刀盘的强度性能已无法满足工程需求。鉴于此,本文建立一套随机载荷作用下TBM刀盘强度可靠性的分析方法。基于刀盘-岩石耦合计算模型获取掘进过程中刀具的破岩载荷;对破岩载荷进行统计分析,得到其分布特性及对应参数,并以此为依据构造刀具破岩的随机载荷,采用蒙特卡罗法对刀盘强度的可靠性进行分析。结果表明:安装半径最大的两把正滚刀的破岩载荷对刀盘强度失效的影响最为显著,其权重可达2/3;在常规岩层下高速施工或在硬岩地层维持正常开挖速度,都将显著降低刀盘的强度可靠性。研究结果可为刀盘的地质适应性设计及TBM施工参数控制提供参考。展开更多
A 3D-finite element model is illustrated that allows for the iterative simulation of the shield drive with its face and grouting pressures by shifting the determined stresses and displacements after each calculation s...A 3D-finite element model is illustrated that allows for the iterative simulation of the shield drive with its face and grouting pressures by shifting the determined stresses and displacements after each calculation step.Analyses are performed for the tunneling of Rio de Janeiro’s Line 4 and compared to the results of analytical limit equilibrium analyses and monitoring results of the actual TBM-drive.展开更多
文摘This paper analyzed the characteristics of welding solidification crack of stainless steels,and clearly re- vealed the the of the deformation in the molten - the pool and the solidification shrinkage on the stress - strain fields in the trail of molten - weld pool.Moreover, rheologic properties of the alloys in solid - liquid zone were also obtained by measuring the hading and unloading deform curves of the steels.As a result, a numerical model for simulation of stress - strain distributions of welding solidifi- cation crack was developed. On the basis of the model,the thesis simulated the driving force of solidifi- cation crack of stainless steels, that is, stress - strain fields in the trail of molten-weld pool with fi- nite element method.
文摘刀盘作为全断面岩石隧道掘进机(Full Face Rock Tunnel Boring Machine,TBM)的直接开挖部件,承受刀具破岩的全部载荷,其强度可靠性是评价TBM刀盘性能的重要指标。受复杂地质条件及刀岩相互作用机制的影响,刀盘在掘进过程中承受的载荷具有很强的随机性,故在单一特定工况下研究刀盘的强度性能已无法满足工程需求。鉴于此,本文建立一套随机载荷作用下TBM刀盘强度可靠性的分析方法。基于刀盘-岩石耦合计算模型获取掘进过程中刀具的破岩载荷;对破岩载荷进行统计分析,得到其分布特性及对应参数,并以此为依据构造刀具破岩的随机载荷,采用蒙特卡罗法对刀盘强度的可靠性进行分析。结果表明:安装半径最大的两把正滚刀的破岩载荷对刀盘强度失效的影响最为显著,其权重可达2/3;在常规岩层下高速施工或在硬岩地层维持正常开挖速度,都将显著降低刀盘的强度可靠性。研究结果可为刀盘的地质适应性设计及TBM施工参数控制提供参考。
文摘A 3D-finite element model is illustrated that allows for the iterative simulation of the shield drive with its face and grouting pressures by shifting the determined stresses and displacements after each calculation step.Analyses are performed for the tunneling of Rio de Janeiro’s Line 4 and compared to the results of analytical limit equilibrium analyses and monitoring results of the actual TBM-drive.
