| Tower cranes are one of the most widely used lifting machines on construction sites today.The safety and stability of tower cranes are greatly affected by geological conditions.Generally,under weak geological conditions,the foundation type of tower cranes often adopts a pile-cap foundation.However,the pile-cap foundation design fails to make full use of the pile-soil interaction,which leads to an increase in engineering costs.However,the tower crane's integrated foundation not only has low construction cost,but also has the characteristics of simple structure,small footprint,low construction difficulty,and fast progress.However,this foundation is directly applied to weak geology,which can neither reflect its advantages nor be economical.CFG pile composite foundation is one of the more commonly used foundation treatment technologies in current engineering practice.It not only has the advantages of high construction efficiency,fast progress,controllable construction quality,but also relatively low construction costs.In order to realize the application of the monolithic foundation of the tower crane on the weak foundation while effectively reducing the engineering cost,facilitating the construction and ensuring the construction quality,the characteristics of the monolithic foundation of the tower crane and the composite foundation of the CFG pile are comprehensively considered.The combination of foundation and CFG pile composite foundation technology makes full use of the advantages of both.At the same time,to some extent,it makes up for the shortcomings of tower crane pile-cap foundation,and also broadens the scope of use of CFG pile composite foundation.In this paper,the CFG pile composite foundation design theory calculation method is first used to design the CFG pile composite foundation under the monolithic foundation of the tower crane,and the most reasonable design scheme is determined through comparison of multiple sets of schemes;The actual foundation-pile-soil model of the project;Finally,ABAQUS was used to carry out a finite element simulation analysis of the model to verify the validity of the scheme design and analyze the stress distribution and displacement of the composite foundation by the pile length,diameter,and cushion thickness Impact of change.The main research contents and conclusions are as follows:(1)By summarizing the existing theoretical research results of CFG pile composite foundation,the reinforcement mechanism of CFG pile composite foundation and the calculation method of its bearing capacity and settlement under themonolithic foundation of tower crane are explained and analyzed;(2)Based on the existing actual engineering geological conditions,the CFG pile composite foundation bearing capacity and settlement calculation method is used to design the composite foundation under the tower crane foundation,and a more optimal design is determined through comparison of multiple groups of schemes Program;(3)Establish a foundation-pile-soil model based on the dimensional parameters determined by the CFG pile composite foundation design scheme under the monolithic foundation of the tower crane,and use ABAQUS to analyze the tower crane foundation under horizontal load,vertical load,overturning moment and horizontal torque.When it acts,the soil and pile stress distribution and displacement of the lower CFG pile composite foundation,and the effects of different pile lengths,pile diameters,and cushion thicknesses on the stress distribution and settlement deformation of the composite foundation;(4)By comparing the simulation value of the finite element analysis with the theoretical calculation value of the CFG pile composite foundation scheme design under the tower crane foundation and obtaining:1)The CFG pile composite foundation design theory is not only applicable to the design calculation of CFG pile composite foundation in high-rise buildings and other fields,but also applicable to the design calculation of CFG pile composite foundation under the tower crane foundation with small acting area and complex forces;2)The stress distribution and settlement deformation of CFG pile composite foundation under the combined action of vertical load,horizontal load,overturning bending moment and horizontal torque are similar to those of a single vertical load,and only due to the influence of the overturning bending moment on the bending moment.There are differences in stress distribution and uneven settlement in the action direction.3)In addition,although the pile length,pile diameter,and cushion thickness help reduce the settlement of the composite foundation,they are all limited by effective size.For the foundation-pile-soil model in this paper,when the pile length exceeds 8m,the pile diameter exceeds 550 mm,and the cushion layer exceeds 250 mm,the effect on the stress distribution and settlement of the composite foundation is no longer significant.The above research content and conclusions are complementary to theapplication method of tower crane monolithic foundation on weak foundation,and also have certain reference significance for the application of CFG pile composite foundation treatment in other areas in small areas of weak soil.Figure[39] table[16] reference[57]... |
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