Study On The Mechanical Properties And Dissipation Capacity Of Ring Net In Passive Flexible Protection

The geological structure of our country with high to the west and low to the east is diversity.With the climate change in recent years,the geological disasters are more frequent.Moreover,because of the sudden,high frequency and high impact kinetic energy,the landfall and rock-fall is a serious threat to the traffic trunk and towns.According to the actual characteristics of landfall and rock-fall and the geological conditions,a large number of technicians accumulated a lot of practical experience.Among them,the passive flexible protection structure is widely used in practical engineering because of its many advantages such as convenient construction,rapid,small interference,standardized production,low cast,strong practicability,beautiful appearance,environmental protection and so on.Ring net is one of the most important parts of the passive flexible protection,but the damage of the ring net is often occurred in practical engineering application.In this paper,the ring net component is taken as the research object and the basic research is carried out by means of theoretical derivation,numerical simulation and comparative analysis of experimental data.The following work is mainly completed in this paper.(1)Based on the theory of energy absorption of materials and structures,the theoretical formula for the energy dissipation of a single ring under the action of two,four and six forces is derived.Compared with the existing results,the correctness of the theoretical derivation is proved which provides a basis for the study of the energy consumption of the ring net.(2)The ring net that has the same size,boundary conditions and impact process in the literature is built by ANSYS/LS-DYNA software.Then the impacts of rock-fall were analyzed under 24kJ and 45kJ.The experimental data in the literature and the results derived under these circumstances were compared in order to prove the correctness of the numerical simulation model.And it provides a reasonable modeling method for the numerical analysis of the dynamic response and the energy consumption of the ring net.(3)By using the modeling method verified by the experimental data,the ring net is established which is 3.3m X 6.6m.First,three kinds of constraints are analyzed respectively and the dynamic response and the maximum energy consumption under different constraints are analyzed and compared.Then,the influence of falling rock gravity on the energy dissipation performance of the ring net that is divided into three kinds is analyzed.Finally,the dynamic response and energy dissipation of the ring net under different impact angles of rock-fall is analyzed.According to the different impact angles,the study can be divided into five cases.(4)By changing the number of transverse and longitudinal rings,different sizes of ring net are established.According to the distribution law of the loading area of the ring net with different sizes under the vertical impact of falling rock,the formula for calculating the energy consumption of ring net is given quantitatively.It provides a theoretical basis based on the energy for the design of energy integrated protection structure system.