Research On Settlement Calcul Ation Method Of CFG Pile Compos Ite Foundation

With the development of the national economy,the scale of the national infrastructure is getting larger and larger.In actual projects,many bad foundations will be encountered,which cannot meet the requirements of the bearing capacity and deformation of the proposed building,and the bad foundations need to be dealt with.In recent years,with the increasingly mature foundation treatment technology,CFG pile composite foundation has better bearing capacity and resistance to deformation.CFG pile composite foundation is used in engineering more,but it is not difficult to find in actual engineering,CFG pile composite foundation The settlement calculated using the existing codes is larger than the actual settlement,that is,the safety factor is larger,and the calculation process is more complicated.Therefore,a simple method for calculating the settlement of the CFG pile composite foundation is proposed to facilitate the practical application of the project.easy to understand.First,the numerical simulation analysis of the composite foundation of single pile and CFG pile is carried out to understand the stress and displacement of the composite foundation of single pile and CFG pile,the stress and displacement of the soil around the pile,the stress state performance of the underlying soil,and then the foundation settlement is calculated according to the code On the basis of the method,a simple method for calculating the settlement of CFG pile composite foundation is proposed.Finally,the feasibility of the formula is verified in conjunction with the actual engineering case,which provides reference value for future engineering design and construction.The main conclusions are:(1)Using FLAC numerical simulation software to analyze the simulation results of CFG single pile and CFG pile composite foundation.The working behavior of CFG single pile is very consistent with the actual situation.Due to the combined action of pile and soil,the CFG pile composite foundation has different working characteristics.Great.(2)The genetic load of the composite ground is shared by the pile and soil.The vertical displacement and stress state of the pile and soil are much more complicated than that of the single pile.It is divided into negative friction resistance,zero and positive friction resistance and changes with the change of the upper load.(3)The final settlement of the CFG pile composite foundation is obtained by the settlement of the reinforcement area and the settlement of the underlying layer.The settlement of the lower layer mainly includes the settlement caused by the earth pressure between the piles,the settlement of the lower layer of the pile end caused by the friction resistance of the pile layer and the end resistance.Calculated by the layer sum method.(4)The compression modulus of the composite foundation is greater than that of the natural foundation of this layer.When the composite foundation modulus correction factor is 2.6,it is more in line with the actual engineering needs.(5)Calculate the foundation settlement based on the average stress of the soil between the piles as the settlement of the composite foundation,and obtain the verification of the measured data of the 15 CFG pile composite foundation.The calculation results of the simple method are in good agreement with the measured data.