| Our country,with its vast territory,many mountains,complicated natural environment.Under the action of frequent earthquake in recent years,natural geological disasters such as rock falling,mountain collapse and debris flow occur frequently.The common methods for the prevention and control of rock falling,collapse and debris flow including: clear,active interception,passive interception,occlusion and so on.Among them,the flexible protection structure has obvious advantages in applicability,safety,economy and environmental protection,so in recent years,the flexible protection structure is widely used in slope protection,railway and highway.In engineering practice,ring net of flexible protection structure is configured by experience,which could lead to safety problem or economic waste.Therefore,it is necessary to carry out related experiments on the ring net,to provide some reference for configuration of the ring net in flexible protection structure.This dissertation mainly includes the following work:(1)On the basis of the “YJ-IID-W” structural mechanical test device,according to the requirements of layout,test load,deformation of ring net in flexible protection structure,four H-beams are designed by ANSYS finite element calculation.The web of H-beams is pierced to a certain distance,and then four boundaries are fixed by the fastening action of the hook screw.Bolts are designed to guarantee the connection of columns of “YJ-IID-W” structural mechanical test device and four H-beams.In addition,the test groups,test loading and data measurement scheme are made.In addition,relevant instruments that meet the requirements of test loading,data acquisition and video shooting are proposed.(2)The monotonic loading experiments are carried out on the ring nets with 5 circles,7 circles and 9 circles.The force and deformation characteristics of different circles ring nets are analyzed and compared.Under the concentrated load,the overall stiffness varies with the load is studied by measured load-displacement curve and the relationship between overall stiffness and load is proposed,which can provide basis for the test load control.In addition,the overall stiffness of ring net in the three kinds of circles is compared by the load-normalized curve.(3)The reloading experiment is carried out on the ring net with 9 circles to study the residual deformation and the change of the overall stiffness,which provide basis for the repeated use of ring net in actual engineering.(4)The numerical simulations of ring nets with different size,boundary constraints,ring diameters and different socket type are given by ANSYS.The deformation characteristics,energy dissipation performance are analyzed and compared,which can provide reference value for selecting different types of ring nets in practical engineering. |
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