Evolution Mechanism of Railway Subgrade Deformation Induced by Reverse Fault Dislocation
In response to the problem of uneven deformation and cracks in railway subgrade crossing active fault zones caused by inter seismic creep and co-seismic viscous slip dislocation in fault zones,a self-developed multi angle and controllable rate L-shaped boundary fault dislocation indoor model test device and numerical simulation calculation were used.The combined damage factor of cohesive force and tensile strength loss of rock and soil was analyzed and considered,revealing the mechanism of deformation evolution of subgrade and foundation induced by reverse fault dislocation under different inclination angles of fault zones and angles between fault zones and line directions.The results show that under the influence of reverse fault dislocation,an S-shaped uplift appears vertically on the top surface of the subgrade,and in the horizontal direction,the subgrade shows overthrust deformation towards the fixed fault plane direction.According to the deformation characteristics of the subgrade slope,the slope can be divided into overthrust deformation zone,overthrust bulging deformation zone,and potential unstable zone.Under reverse fault dislocation,the fracture above the fault dislocation plane belongs to tensile fracture,while the large-scale fracture above the fixed fault plane is caused by both tensile deformation and shear deformation,belonging to a mixed tensile shear fracture.For the arc-shaped fracture between the deep static zone and the wedge-shaped shear zone of the foundation,as the fracture gradually extends towards the surface,the fracture properties gradually transform from shear fracture to tensile shear mixed fracture.
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