Simulation Research On The Safety Of The Guardrail Of The Tunnel Entrance Based On Finite Element

In recent years,with the continuous development of highway tunnel construction,my country has made remarkable achievements in tunnel construction,which has further improved the efficiency of road transportation.Due to the particularity of the geographical environment at the entrance of the tunnel,vehicle accidents occur frequently,and such accidents will cause serious losses once they occur.The guardrail is an important facility to ensure the safety of vehicles at the entrance of the tunnel.Therefore,it is of great significance to carry out research on the safety of the guardrail at the entrance of the tunnel.The thesis studies the safety of guardrails at the entrance of highway tunnels by finite element simulation.First,analyze the types of guardrails at the entrance of common highway tunnels,and determine the safety assessment requirements for guardrails at the entrance of tunnels in combination with relevant domestic and foreign standards.Second,according to the crash test standards,18 t flat-top large trucks are used as collision vehicles,relying on actual tunnels and guardrails Build three types of finite element models of tunnel entrance guardrails;control collision and calculation parameters,establish a vehicle-guardrail collision finite element system at tunnel entrance,submit the finite element model to the solver LS-DYNA for collision calculation;finally,through Hyperview Post-processing the output data,combined with the safety evaluation requirements of the guardrail,evaluates the safety of the guardrails of the three types of tunnel entrance sections,and conducts variableparameter studies on the guardrails to analyze the impact of the collision speed and collision angle on the guardrails.The research results show that due to the poor barrier performance of the corrugated beam guardrail at the entrance of the tunnel,the vehicle collides with the tunnel wall after a collision with it,which makes the vehicle and occupants face greater risks and should not be placed directly at the entrance of the tunnel;the corrugated beam transitions to The safety of the concrete wing wall guardrail and the double layer beam guardrail meets the safety assessment requirements of the tunnel entrance section guardrail,and is more suitable for installation at the tunnel entrance.Among them,the double layer beam guardrail has better cushioning performance.The transition from corrugated beams to concrete wing wall guardrails shows better blocking and guiding performance.At the same time,the smaller the collision speed and collision angle of the vehicle,the more stable the state of the vehicle after the collision,and the lower the risk to the vehicle and occupants.The results can provide some theoretical support for the setting of guardrails at the entrance of highway tunnels.