| Passive passive protection system technology is often used to prevent slopes from falling,falling rocks and natural disasters.The occurrence of natural disasters has been frequent on slopes at home and abroad.Steel columns in passive flexible protection systems are often distorted or bent by large external forces.The steel column is directly damaged by the impact of rockfall,which leads to the direct destruction of the passive protection system.For this reason,the mechanical properties and impact resistance of the steel column directly determine whether the slope passive flexible protection system can play a role.This paper mainly uses the finite element software ABAQUS/CAE to establish the static model of different section steel columns and uses ABAQUS/Explicit to establish nonlinear dynamical models for rocks impacted by rockfalls with different sections.In this paper,the optimal section form selected by numerical simulation is used to establish the standard of anti-collision energy level.The main research results are as follows:(1)The static model of steel columns with different sections was established by using ABAQUS / Standard module.The maximum displacement and the maximum stress are higher than those of hollow square steel column,hollow octagonal column,hollow hexagonal column and hollow circular column.The common I-beam has the largest torsional shear stress under the influence of a pair of couple in the five kinds of cross-section steel columns.As the number of regular polygons increases,the torsional shear stress decreases.The maximum value of the torsional shear stress is minimized when the section is a hollow circular steel column.Hollow round steel column cross-section is the best among five sections in terms of torsional deformation resistance.(2)There are five main types of rock falling movements: rockfall,rockfall,bounce,roll and rockfall.The calculation method of rockfall movement will be five different types of sports rockfall into three methods.The relationship between the drop height H0 of the rockfall and the pre-collision velocity V0 of the steel column in the model is deduced.(3)In the nonlinear dynamic model established by ABAQUS/Explicit:Among the three types of steel columns,hollow square steel column reaches the limit strength assoon as possible at different speeds of falling rock.Hollow square steel column is not suitable as a slope protection system column.Through the analysis of stress,displacement,and energy conditions,the general I-shaped steel column,hollow square steel column and hollow circular steel column are obtained.Among the three steel columns,the hollow circular steel column is more resistant to deformation than the ordinary I-beam and hollow square.The steel column is more capable.(4)In the nonlinear dynamic model established by ABAQUS/Explicit:Under the different qualities of rockfall,the maximum stress value of the hollow round steel column increases with the increase of the falling rock radius.The ability of the hollow round steel column to maintain the original shape is higher than that of the ordinary I-shaped steel column and hollow square after being impacted by the falling rock.Hollow round steel column is always bent in the positive axis.Hollow round steel column is not lateral buckling instability of the hollow round steel column.Through the analysis of stress,displacement and energy conditions,it is concluded that the hollow circular steel column has better resistance to external collisions than ordinary I-pillar and hollow square steel columns.Hollow round steel column is more suitable as a slope protection system column.(5)According to relevant specifications of steel structure and round steel column,six types of hollow circular steel column anti-collision energy levels have been developed. |
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