Reinforcement Method And Numerical Simulation Of Guardrails On Both Sides Of Existing Railways

The railway project has developed rapidly and usually has guardrails on both sides However,with the increase of working hours and environmental factors,the concrete that constitutes the guardrail is aging,and the bearing capacity of the guardrail will be greatly reduced,posing serious safety hazards.In order to improve the bearing capacity of the guardrail,relevant scholars have proposed a number of reinforcement methods,and carried out a large number of experimental studies,but there are still many technical deficiencies in engineering applications,and some reinforcement techniques can not meet the actual needs of the reinforcement effect of the guardrail.Therefore,on the basis of inheriting the existing research results,it is urgent to explore more effective reinforcement methods.The high-toughness cement board is used as a factory-prefabricated board with good toughness and high strength.The use of high-toughness cement slabs for reinforcement of the guardrail is simple,economical and has little impact on the environment.Therefore,this paper focuses on the use of high-toughness cement slabs to reinforce the guardrail,and has carried out the following research:First of all,the beam similar to the upper structure of the guardrail was first strengthened,because the structure of the guardrail was more complicated.The finite element model of the reinforced beam was established by using ABAQUS.The simulation results were compared with the experimental results,and the accuracy and effectiveness of the finite element simulation method were verified.The variation law of concrete stress during the failure process was explored.Secondly,the numerical model of the reinforced guardrail was established,using the same material constitutive model and contact relationship.The damage process of the reinforced guardrail was numerically simulated,and the simulation results and test results were compared to verify the correctness of the numerical model.At the same time,the variation law of the maximum principal stress of concrete,the Mises stress of steel bars and the stress of high toughness cement slabs during the loading process were analyzed.Thirdly,a finite element model of the unreinforced guardrail was established,based on the above numerical simulation method.The load-displacement curve,the special moment load and the crack diagram of the unreinforced guardrail and the reinforced guardrail were compared.The improvement effect of the reinforcement method on the mechanical properties of the guardrail was analyzed,and the mechanism of reinforcement was explored.Finally,the parametric analysis of high toughness cement board thickness,high toughness cement board length and cement mortar thickness was carried out.The influence of these factors on the performance of the guardrail after reinforcement was further analyzed.In summary,the finite element model of the reinforced rear beam and the reinforced guardrail was established,and the parametric analysis of the reinforced guardrail was carried out.Studies have shown that when the thickness of the high-toughness cement board is less than 48 mm,the increase of the thickness of the board has a significant improvement on the mechanical properties.When the thickness is greater than 48 mm,the thickness of the board is not improved for the mechanical properties;when the length of the high-toughness cement board is 600 mm,It can effectively improve the mechanical properties of the guardrail and meet the economic requirements.Changing the thickness of the cement mortar has no obvious influence on the mechanical properties of the guardrail.