Study On The Failure Mechanism And Control Technology Of Deep Cutting Slope Located On High-cold Area

The complex engineering nature of expansive soils often causes serious damages to the structures built in this area.There is "every cut must slide" argument when building railway subgrade slope in the expansive soil area in China.In high latitude cold area,the expansive soil has significant freezing and thawing properties besides the general expansive soil properties.The deep cutting slope in the high latitude cold area has always been the weak link of the railway engineering.Therefore,it is of great theoretical and engineering significance to study the failure mechanism and control technology of the deep cutting slope in the high latitude cold area.In this paper,a series of research on the failure mechanism and prevention and control technology of deep cutting slope of expansive soil in JiTuHun high-speed railway were carried out by using the indoor experiment of expansive soil mechanical properties,field measurement and finite element numerical simulation.Firstly,the expansive soil samples were collected and the internal mechanics experiment of expansive soil was carried out.The experiment of drying and wetting of expansive soil and the experiment of freeze-thaw cycle were studied systematically.The changes of expansive soil structure caused by freeze-thaw cycle and wet and dry cycle were analyzed in detail.The relationship between the shear strength index and the number of freeze-thaw cycles of expansive soil was given by the direct shear test.Next,the finite element method was used to analyze the failure mechanism of deep cutting slope in the high latitude cold area,and it was concluded that the engineering property is the root cause of the deep cutting slope,and that engineering activities and the external environment are key inducing factors.The failure mechanism of the expansive cutting slope caused by rainfall,dry and wet circulation and freezing and thawing was mainly studied.It was pointed out that the fracture is the root cause of the shallow landslide when it is exposed to rainfall.Finally,the finite element model of expansive soil deep cutting slope was established,and the reason of the first failure of deep cutting slope was analyzed emphatically by finite element numerical simulation.At the same time,in the slope protection scheme the results calculated by the finite element software were compared with the results of the field monitoring data.A feasible control technology for the deep cutting slope of the expansive soil in the high latitude cold area was given.