落石冲击作用下不同连接方式被动防护网的受力分析

Force Analysis of Passive Protection Nets with Different Connection Modes under Rockfall Impact

以常用的RX-025型被动防护网为原型,考虑材料非线性、几何非线性及摩擦接触等因素,运用ANSYS软件,建立钢柱与钢丝绳网及钢柱与基础采用不同连接方式的被动防护网结构模型,进行不同落石冲击能量作用下不同连接方式被动防护网的受力性能研究。结果表明:上下支撑绳对钢丝绳网的垂直变形影响很大;在相同落石冲击能量作用下,钢柱与钢丝绳网仅在柱顶和柱脚处连接(两点连接)时,结构的变形比多点连接明显,结构受到的最大冲击荷载、拉锚绳及支撑绳的受力更小,耗能能力更好;钢柱与基础间铰接连接时可显著降低钢柱轴力,提高被动防护网结构的防护能级;建议被动防护网的钢柱与钢丝绳网间优先采用两点连接,钢柱与基础间优先采用铰接连接。

The common RX-025 type passive protection net was used as prototype.Considering such factors as material nonlinearity,geometric nonlinearity and frictional contact,the structure model of passive protection net with different connection forms of the main components between steel column and steel wire net,steel column and foundation was constructed by ANASYS software to study the mechanical behaviors of the passive protection net with different connection forms under different rockfall impact energy.The results indicated that the top and bottom supporting rope had great influence on the vertical deformation of steel wire net.Under the same rockfall impact energy,when the steel column and steel wire net was connected only at the top and the base of column（two-point connection）,the structure deformation was more obvious than that of multi-point connection,the maximum impact load imposed on the structure was smaller.The force on anchor rope and supporting rope was smaller too,and the energy dissipation capacity was better.When hinge joint was used to connect steel column and foundation,the axial force of steel column could be significantly reduced and the protection level of passive protection net structure was improved.It is suggested that two-point connection should be preferentially adopted for the steel column and steel wire net of passive protection net,and hinge joint for connecting steel column and foundation.