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Stress wave propagation and incompatible deformation mechanisms in rock discontinuity interfaces in deep-buried tunnels
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作者 Cong Zhang Zhende Zhu +2 位作者 Shanyong Wang Xuhua Ren Chong Shi 《Deep Underground Science and Engineering》 2022年第1期25-39,共15页
Complex weak structural planes and fault zones induce significant heterogeneity,discontinuity,and nonlinear characteristics of a rock mass.When an earthquake occurs,these characteristics lead to extremely complex seis... Complex weak structural planes and fault zones induce significant heterogeneity,discontinuity,and nonlinear characteristics of a rock mass.When an earthquake occurs,these characteristics lead to extremely complex seismic wave propagation and vibrational behaviors and thus pose a huge threat to the safety and stability of deep buried tunnels.To investigate the wave propagation in a rock mass with different structural planes and fault zones,this study first introduced the theory of elastic wave propagation and elastodynamic principles and used the Zoeppritz equation to describe wave field decomposition and develop a seismic wave response model accordingly.Then,a physical wave propagation model was constructed to investigate seismic waves passing through a fault,and dynamic damage was analyzed by using shaking table tests.Finally,stress wave attenuation and dynamic incompatible deformation mechanisms in a rock mass with fault zones were explored.The results indicate that under the action of weak structural planes,stress waves appear as a complex wave field decomposition phenomenon.When a stress wave spreads to a weak structural plane,its scattering may transform into a tensile wave,generating tensile stress and destabilizing the rock mass;wave dynamic energy is absorbed by a low-strength rock through wave scattering,which significantly weakens the seismic load.Wave propagation accelerates the initiation and expansion of internal defects in the rock mass and leads to a dynamic incompatible deformation.This is one of the main causes for large deformation and even instability within rock masses.These findings provide an important reference and guide with respect to stability analysis of rock mass with weak structural planes and fault zones. 展开更多
关键词 deep-buried tunnels fractured rock mass incompatible deformation mechanism rock interfaces stress wave propagation model
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Incompatible thermal deformation of interlayers and corresponding damage mechanism of high-speed railway track structure 被引量:1
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作者 Guotang Zhao Lei Zhao Yu Liu 《High-Speed Railway》 2023年第1期37-46,共10页
In the service period,the instability of ballastless track bed are mostly related to the damage of interlayers which are mainly resulted from the incompatible thermal deformation of interlayers.The temperature field w... In the service period,the instability of ballastless track bed are mostly related to the damage of interlayers which are mainly resulted from the incompatible thermal deformation of interlayers.The temperature field within the ballastless track bed shows significant non-uniformity due to the large difference in the materials of various structure layers,leading to a considerable difference in the force bearing of different structure layers.Unit Ballastless Track Bed(UBTB)is most significantly affected by temperature gradient.The thermal deformation of interlayers within UBTB follows the trend of ellipsoid-shape buckling under the effect of the temperature gradient,resulting in a variation of the contact relationship between structure layers and a significant periodic irregularity on the rail.When the train travels on the periodically irregular rail,the structure layers are locally contacted,and the contact zone moves with the variation of the wheel position.This wheel-followed local contact greatly magnifies the interlayer stress,causes interlayer damage,and leads to a considerable increase in the bending moment of the track slab.Continuous Ballastless Track Bed(CBTB)is most significantly affected by the overall temperature variation,which may cause damage to the joint in CBTB.Under the combined action of the overall temperature rise and the temperature gradient,the interlayer damage continuously expands,resulting in bonding failure between structural layers.The thermal force in the continuous track slabs will cause the up-heave buckling and the sudden large deformation of the track slab,and the loss of constraint boundary of the horizontal stability.For the design of a ballastless track structure,the change of bearing status and structural damage related to the incompatible thermal deformation of interlayers should be considered. 展开更多
关键词 High-speed railway Ballastless track bed incompatible thermal deformation Damage mechanism
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Diagnosis of the Thermal Bow of a Shaft in a Three Stage Centrifugal Compressor 被引量:3
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作者 LIAOMing-fu LUYa-Juan 《International Journal of Plant Engineering and Management》 2003年第1期1-8,共8页
In practice many turbo-machines driven by motors are started up tooperational speed within a very short time, i. e. in less than 20 seconds. For this type of machinesthe compatibility of thermal deformation of the rot... In practice many turbo-machines driven by motors are started up tooperational speed within a very short time, i. e. in less than 20 seconds. For this type of machinesthe compatibility of thermal deformation of the rotor structure must be taken into account in themachine design, or the thermal deformation will be constrained and a huge resultant force can causethe shaft bending and consequently resulting in violent vibrations. In this paper, detection ofthermal bow of a shaft in a three stage centrifugal compressor in a petrochemical plant ispresented. The diagnostic results show that the thermal bow was induced by the incompatibility ofaxial thermal deformation of the rotor structure. A remedial action allowing free axial thermalexpansion of the outer parts of the rotor is suggested. 展开更多
关键词 thermal bow compressor incompatibility of thermal deformation vibration DIAGNOSIS
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