RESEARCH ON THE DEFORMATION MECHANISM OF CUTTING SLOPE UNDER THE COUPLING ACTION OF FREEZE-THAW AND DYNAMIC LOAD

The geological, climate, and environmental conditions of the Sichuan-Tibet Railway crossing area are complex, and there will be a large number of unresolved scientific and technological problems during its construction and operation. Aiming at the long-term freeze-thaw cycle of the rock mass in the alpine mountainous area, coupled with the long-term dynamic train load, the damage evolution law of the rock mass, and its influence on the stress state and deformation trend of the cutting slope, it will be the Sichuan-Tibet Railway disaster reduction and prevention, which is one of the key issues that needs to be solved urgently. Based on this, this article analyzes the measured data to obtain the law of traffic vibration propagation, that is, the farther the track is, the smaller the peak speed, and the vertical speed is greater than the horizontal direction. Based on this, the Z-direction equivalent load model is established; through indoor rock freezing and thawing cyclic test found that as the number of freeze-thaw cycles increases, the peak strength and elastic modulus of the rock are significantly weakened. For example, the peak strength and elastic model decrease, and the compaction section becomes longer. Compared with the PFC^2D numerical simulation analysis, it can be seen that in the early freeze-thaw stage, the slope deformation is mainly vertical displacement. With the increase in the number of freeze-thaw cycles, the increase in the horizontal displacement of the slope is greater than the vertical; freeze-thaw and dynamic load coupling conditions Under this condition, the horizontal deformation of the slope will be accelerated, and slope failure and instability will easily occur. The research results can provide a certain scientific basis and theoretical support for slope risk prevention and control during the operation period of the Sichuan-Tibet Railway and similar projects.