Flexible Multi-body Dynamics Simulation Of Cable-supported Structure For Rockfall Protection

The tunnel portal of the mountain traffic trunk line often encounters rockfall invasion.In order to ensure the safety of operations,the rockfall protection at the portal is extremely important.The shelter tunnel structure is usually set at the portal of traffic trunks.However,there is currently a general lack of research reports on shed structure subjected to rockfall and the structural dynamic behavior at home and abroad.Therefore,research on the protection of tunnel portal has important engineering and theoretical values for improving the safety of rockfall protection.Therefore,this paper proposed a new type of cable-supported buffer structure,which can be integrated with any existing shed structure to form a “flexible buffer shed system”.In this dissertation,nonlinear flexible multi-body dynamics simulations are performed for cablesupported flexible buffer structures.The main research contents are as follows:Based on the research background of rockfall disaster prevention and control,the research status of commonly used shed structures in traffic trunk portal is studied(Chapter 1).The current status of research on shed structure and buffer layer(structure)were analyzed,and the existing problems of sheds in flexible shed are summarized.Finally,the content of this paper is given.The cable-supported flexible buffer structures system was designed and established(Chapter 2).This paper analyzed the composition of the structural system,the structure force,transmission force,and buffer characteristics.The integration method with the existing typical shed structure.was put forward.The mechanical behavior of the structural members were investigated,including the deformation characteristics of the ring nets,the principle of the energy dissipation devices,and contact-slip characteristics of support ropes(Chapter 3).The research showed that the internal force and deformation of ring nets,support ropes,flexible supports and cablesupported columns in the impact zone were relatively large,and the non-impact zone was less affected by the impact.The system mainly relied on the energy dissipation devices and ring nets to absorb energy,while steel wire ropes and supporting steel structures consume very little energy.The supporting steel structure was basically in elastic.The integrated application of Cable-supported buffer structure and steel sheds was studied(Chapter 5).The integrated design of the Cable-supported buffer structure and the steel structure shed was realized,and the nonlinear impact dynamic analysis was carried out to study the dynamic response of the flexible shed.The results showed that: under the condition of initial rockfall energy of 1000 kJ,the flexible shed could still achieve self-cleaning function without structural damage.The flexible shed had the feature of “partition force”,and the nonimpact contact area is less affected by the impact of the rockfall.Flexible shed could rely on the energy dissipation devices and ring nets to absorb the impact energy of the rockfall,avoiding the damage and energy consumption of the structure.Reasonable setting ensured that the steel structure was in a elastic working state and can be reused.