Research On Damage Mechanism And Block Structure Design Of Debris Flow Subgrade

Debris flow disaster is an important factor in the destruction of highway subgrade and its structure in the western mountainous area.Along with the acceleration and deepening of the "Silk Road Economic Belt" national strategy and the great development of the western region,debris flow disasters often occur in the western mountainous areas due to the increase of human activities and the unique environment and geological conditions in the western mountainous areas.The debris flow disaster damage on the subgrade and its blocking structure is to solve the problem of mountainous highway.By analyzing the development of debris flow and the characteristics of debris flow and dynamic characteristics in Dongchuan project area,the failure mechanism of debris flow subgrade,the stress and deformation characteristics of debris flow subgrade and block structure are studied in order to carry out the optimization design of the roadbed and block structure of debris flow,and to compare the size and form and mining of the roadbed side of the retaining structure.With the optimized design of the discarded tire buffer layer,the stress and deformation of the subgrade and block structure are analyzed,and the design and technical reference for the debris flow subgrade protection are provided.Based on the analysis of the temporal and spatial distribution characteristics of typical debris flow development and the dynamic characteristics of debris flow,based on the principle of fluid solid coupling of debris flow subgrade,the k-epsilon turbulence model of debris fluid is used to simulate the two-dimensional numerical simulation with the finite element software ADINA,and the failure mechanism of the debris flow subgrade is analyzed and the roadbed-blocking under the impact of debris flow is discussed.The stress and strain characteristics of the retaining structure and the optimization of the roadbed block structure are studied.The results show that the subgrade is rapidly deformed by the direct impact of the debris flow,and the stress and displacement of the subgrade will increase with the impact of the debris flow.In view of the characteristics of debris flow subgrade failure,the subgrade is protected.The stress of the subgrade block structure reaches the peak with the impact of the debris flow faucet.The maximum stress is found at the left and right side of the retaining structure and the contact surface from 0 to 2.5m,and the maximum stress is 0.19497 MPa.The displacement is in a certain range from the beginning of the rapid increase to a certain extent of repeated fluctuations.In view of the change law of subgrade protection with general gravity retaining structure,the size and form of the roadbed side of the increasing block structure and the buffer layer of abandoned tires are used to protect the roadbed block structure.The maximum stress and the peak value of the vertical and horizontal displacement of the subgrade and block structure are obviously reduced,and the economy is considered.It is recommended that the side slope of the retaining structure roadbed is 15 degrees,and the thickness of the buffer layer of the scrap tire is d 1.0m.Considering the use of the discarded tire buffer layer can effectively reduce the impact force of debris flow to the roadbed block structure,and the size and form of the roadbed side of the retaining structure is more prominent to reduce the displacement of the roadbed and block structure.It is suggested that two protective measures be adopted at the same time to double protection of the roadbed block structure.