Stress response of a tension leg platform （TLP） in extreme environments was investigated in this paper. A location on one of the gussets was selected as the object point, where directional stresses were numerically ...Stress response of a tension leg platform （TLP） in extreme environments was investigated in this paper. A location on one of the gussets was selected as the object point, where directional stresses were numerically simulated and also experimentally verified by a strain gage. Environmental loading and the platform＇s structural strength were analyzed in accordance with industrial standards, utilizing linear wave theory and the finite element method （FEM）. The fast Fourier transform technique was used to calculate the stress response amplitude operators （RAO） from the records of measurements. A comparison was performed between the stress RAO of the numerical simulation and that of the actual measurements. The results indicated that the stress RAO of the numerical simulation fitted well with measured data at specified wave headings with different periods.展开更多
We consider rock burst to be a dynamic disaster similar to earthquakes,rapid land sliding,or coal mine gas dynamic disasters.Multi-scale mechanical principles imply the same mechanism of damage evolution proceeds the ...We consider rock burst to be a dynamic disaster similar to earthquakes,rapid land sliding,or coal mine gas dynamic disasters.Multi-scale mechanical principles imply the same mechanism of damage evolution proceeds the catastrophe.Damage may occur at various scales from a meso-scopic scale to a macroscopic,or engineering scale.Rock burst is a catastrophe at the scale of the engineering structure,such as a tunnel cross section or the work face of a long wall mine.It results from dynamic fracture of the structure where microscopic damage nucleates,expands,and finally propagates into a macroscopic sized fracture band.Rock burst must,therefore,undergo a relatively long development,or gestation,time before its final appearance.In this paper,a study of rock burst within a deeply buried tunnel by numerical methods is described.The results show that during rock burst gestation the distributed microscopic damage in the rock surrounding the tunnel localizes,intersects,and then evolves into a set of concentrated ''V'' shaped damage bands.These concentrated damage bands propagate in the direction of maximum shear as shearing slide bands take shape.Rock burst happens within the wedge separated by the shear bands from the native tunnel rock.An analysis of the wedge fracture shows that the unloading effects result in rock burst and rapid release of the strain energy.The implications for rock burst prediction in tunnels are that:(1) rock burst develops in the upper arch corners of in the tunnel cross section prior to developing in other zones,so good attention must be paid there;(2) all monitoring,prevention,and treatment of rock burst should be done during the gestation phase;(3) the shear bands contain abundant information concerning the physics and mechanics of the process and they are the foundation of physical and mechanical monitoring of acoustic emission,micro seismic events,stress,and the like.Thus a special study of the shearing mechanism is required.展开更多
基金supported by the Fund of "111 Project" (Grant No.B07019) from the State Administration of Foreign Experts Affairs and the Ministry of Education of China
文摘Stress response of a tension leg platform （TLP） in extreme environments was investigated in this paper. A location on one of the gussets was selected as the object point, where directional stresses were numerically simulated and also experimentally verified by a strain gage. Environmental loading and the platform＇s structural strength were analyzed in accordance with industrial standards, utilizing linear wave theory and the finite element method （FEM）. The fast Fourier transform technique was used to calculate the stress response amplitude operators （RAO） from the records of measurements. A comparison was performed between the stress RAO of the numerical simulation and that of the actual measurements. The results indicated that the stress RAO of the numerical simulation fitted well with measured data at specified wave headings with different periods.
基金supports are from the National High Technology Research and Development Program of China (No.2008Aa062104)he Key Discipline of Engineering Mechanics of Henan Province and the Key Discipline of Solid Mechanics of Henan Polytechnic University
文摘We consider rock burst to be a dynamic disaster similar to earthquakes,rapid land sliding,or coal mine gas dynamic disasters.Multi-scale mechanical principles imply the same mechanism of damage evolution proceeds the catastrophe.Damage may occur at various scales from a meso-scopic scale to a macroscopic,or engineering scale.Rock burst is a catastrophe at the scale of the engineering structure,such as a tunnel cross section or the work face of a long wall mine.It results from dynamic fracture of the structure where microscopic damage nucleates,expands,and finally propagates into a macroscopic sized fracture band.Rock burst must,therefore,undergo a relatively long development,or gestation,time before its final appearance.In this paper,a study of rock burst within a deeply buried tunnel by numerical methods is described.The results show that during rock burst gestation the distributed microscopic damage in the rock surrounding the tunnel localizes,intersects,and then evolves into a set of concentrated ''V'' shaped damage bands.These concentrated damage bands propagate in the direction of maximum shear as shearing slide bands take shape.Rock burst happens within the wedge separated by the shear bands from the native tunnel rock.An analysis of the wedge fracture shows that the unloading effects result in rock burst and rapid release of the strain energy.The implications for rock burst prediction in tunnels are that:(1) rock burst develops in the upper arch corners of in the tunnel cross section prior to developing in other zones,so good attention must be paid there;(2) all monitoring,prevention,and treatment of rock burst should be done during the gestation phase;(3) the shear bands contain abundant information concerning the physics and mechanics of the process and they are the foundation of physical and mechanical monitoring of acoustic emission,micro seismic events,stress,and the like.Thus a special study of the shearing mechanism is required.
