Dynamic Response And Performance Impact Analysis Of The Flexible Shed-tunnel In Rockfall

The topography and geological conditions of our country are very complicated,two-thirds of the land is mountain land,but the mountain land is the main area of rockfall disaster.Therefore,the study of rockfall disaster protection is very important.The protection measures in actual engineering are mainly divided into active and passive protection.All kinds of protective measures have their own characteristics and scope of use.It is generally believed that using shed-tunnel structure or stone cut off wall is the most effective engineering measure for the prevention and control of rockfall.In this context,it is necessary to study the shed-tunnel structure.This not only has theoretical significance,but also has great economic value.The traditional reinforced concrete structure,due to its own weight and big basic size,long working period in construction and maintenance,is not suitable for the development trend.Therefore,this paper mainly focuses on the analysis and research of the flexible tunnel shed.First of all,we have expounded the traditional reinforced concrete tunnel shed and flexible tunnel shed respectively,compared the stress characteristics and research status of them in detail,and put forward that flexible tunnel shed has great prospects for development.Secondly,we give an overview of the basic components,structure and transfer mechanism of the flexible tunnel shed,and summarize the main methods of the rockfall motion trajectory calculation.Then,through an engineering example,we set up the ANSYS/LS-DYNA numerical model of partial flexible shed-tunnel structure,studied the dynamic response characteristics in the process of rockfall impact,and through the establishment of different working condition,starting from four aspects of energy,deformation,axial force and reaction force,to study and analyse rock fall initial velocity,radius and the influence of strut spring rigidity on structure performance.Finally,through the field test,we compared the theoretical value with the experimental value to prove the accuracy of the numerical simulation process,and further test the performance of the flexible shed-tunnel structure energy dissipation system.