| With the development of the current project,the types of buildings are becoming wider and wider,and more and more large-scale buildings and super-tall buildings are being built.Super-long piles are widely used due to their large bearing capacity.When the super-long pile is used,it may be applied to different foundations,and when the same foundation is used,the constraints may be different,and the pile itself may have defects,resulting in more and more long The pile is used under different working conditions.The super-long piles under different working conditions are prone to buckling damage when they are subjected to a large vertical direction force due to the relatively large length.Therefore,it is important to know the factors affecting the buckling stability of piles under different working conditions,and to prevent the buckling damage of super-long piles under different working conditions.Based on the achievements of scholars,this paper will carry out the work and research in the following aspects:(1)Summarize the significance and research status of the study of buckling stability of super-long piles under different working conditions;(2)The stress of super-long piles in soft soil foundation is analyzed,and the calculation model of buckling critical load of super-long piles in soft soil area is established.Using the energy method,the combined soil resistance model of C method and constant method is used to free the pile top.The buckling critical load under the three constraints of the pile top and the top of the pile is calculated.The actual engineering example is used to analyze the pile length,pile diameter,pile body weight,pile side friction force and pile under three constraints.The effects of elastic modulus,resistance coefficient of foundation soil,flexural function and constant soil resistance coefficient on buckling stability of super-long piles,and relevant conclusions are obtained,which provides some theoretical references for reducing buckling damage of super-long piles in soft soil foundation;(3)The stress of the super-long piles on the slope foundation is analyzed.The calculation model of the buckling critical load of the super-long piles on the slope foundation is established.Using the energy method,the combined soil resistance model of the C method is used for the pile top free,the pile top joint and the pile.The buckling critical loads under three kinds of constraints are calculated.The actual engineering examples are used to analyze the pile diameter,the length of the free section,the length of the landslide section,the length of the embedded end,and the slope.foundation soil proportional coefficient and pile elastic modulus on the buckling stability of super-long piles are obtained.Relevant conclusions are provided to provide some theoretical reference for reducing the buckling damage of super-long piles in slope foundation.(4)Analyzed the stress of super-long piles in karst foundation,and established the calculation model of buckling critical load of super-long piles in karst foundation.Using the energy method,the combined soil resistance model of m method and constant method is used to pile the super-long piles.The buckling critical loads under three boundary conditions: top free,pile top articulation and pile top embedding were calculated.A practical engineering example was selected to analyze the karst height,the number of karst and the karst caves under three constraints.The influence of position on the buckling critical load of super-long piles;the relevant conclusions are obtained,which provides some theoretical reference for reducing the buckling damage of super-long piles in karst foundation;(5)The stress condition of the super-long pile with defects is analyzed,and the calculation model of the buckling critical load of the super-long pile with defects is established.The combined soil resistance model of the m method and the constant method is used for the super-long pile.The buckling critical loads of super-long piles under the three boundary conditions of pile top free,pile top articulation and pile top embedding were calculated.A practical engineering example was selected to analyze the faulty superlong piles under three constraints.The influence of factors such as defect height,defect width and defect location on the buckling critical load of super-long piles;relevant conclusions are obtained,which provide some theoretical reference for reducing buckling damage of super-long piles with defects;... |
