新型地锚张弦梁式泥石流格栅坝稳定性分析

Stability analysis of novel ground anchor and beam string debris flow grid dam

为防止新型地锚张弦梁式泥石流格栅坝在强度破坏前发生稳定性破坏,导致整个结构失效,基于新结构构件受力的简化计算方法对其局部稳定性和整体稳定性进行了分析。采用能量法推导了局部失稳时张弦梁结构平面内屈曲荷载公式,避免了直接求解张弦梁结构的内力,极大地提高了求解效率;分析了矢跨比和垂跨比对屈曲荷载的影响;提出了空库、半库和满库工况下新结构整体失稳破坏的安全稳定性系数计算方法。结合理论分析,升级了新结构设计计算软件,优化了算法,开发了稳定性计算模块。利用SAP2000建立了有限元模型对理论分析进行验证,结果表明:得到的张弦梁结构平面内的屈曲荷载计算值与有限元计算值吻合较好,可作为张弦梁结构平面内稳定性设计的依据;矢跨比和垂跨比的增大均有利于提高张弦梁结构的平面内稳定性;新结构工程应用时,张弦梁结构参数的选取可参考两铰拱给出,其空库和半库工况下整体失稳破坏要早于强度破坏,应着重考虑其整体失稳破坏,特别是空库工况下中柱的倾覆。

In order to prevent the stability failure of the novel ground anchor and beam string debris flow grid dam before the strength failure,resulting the whole structure fails.Based on the simplified calculation method of novel structural components,this paper analyzes the local stability and overall stability.The energy method is used to derive the in-plane buckling load formula of the beam string structure under local instability.This method avoids directly solving the internal force of the beam string structure and greatly improves the solving efficiency.The influence of rise-span ratio and sag-span ratio on buckling load are analyzed.The calculation method of the safety stability factor of the overall instability failure of the novel structure under empty,half and full storage conditions is proposed.Combined with theoretical analysis,the new structural design calculation software is upgraded,the algorithm is optimized and the stability calculation module is developed.The finite element model is established by SAP2000 to verify the theory,the results show that:the calculated value of in-plane buckling load of beam string structure is in good agreement with that of finite element method,which can be used as the basis for stability design of beam string structure in-plane;the increase of rise-span ratio and vertical-span ratio is beneficial to improve the in-plane stability of beam string structure;In the application of novel structure engineering,the selection of beam string structure parameters can be given by referring to the two-hinged arch.The overall instability failure under empty and half storage conditions are earlier than that under the strength failure,and the overall instability failure should be emphatically considered,especially the overturning of the middle column under empty storage conditions.