Research On The Behavior Of CFG Pile-soil Interaction In Soft Soil Area In Shanghai

In recent years,with the economic development of the Yangtze River Delta,a large amount of construction work needs to be carried out in the soft soil area.Therefore,higher requirements have been put forward for the treatment of soft soils.Cement Fly-ash Gravel Pile means a cement fly ash gravel pile,which is mixed with gravel,stone chips,sand,fly ash,and water.It is made of various pile forming machines and has a certain strength.Variable strength piles.At present,the design theory and treatment methods of CFG pile composite foundation present diversity and uncertainty.The factors such as the length and diameter of the pile have different degrees of influence on the bearing capacity of CFG pile composite foundation.Therefore,more in-depth research work on the influencing factors of CFG pile-soil interaction is needed.The paper summarizes the factors affecting the pile material properties,applicability,reinforcement mechanism,stress characteristics and bearing capacity of CFG pile composite foundation,taking the Shanghai Fengcheng project as an example,and calculating it through theoretical and numerical simulation methods.The relationship between CFG pile length,pile diameter,pile spacing and foundation bearing capacity and settlement amount,and monitoring of ground settlement for a period of 45 days,in order to provide reference for design and construction of CFG pile foundation engineering in Shanghai soft soil area.The theoretical calculation results show that when the pile length is 18m,22m,26m,and 30m,respectively,the corresponding composite foundation settlements are 56.3mm,52.9mm,49.6mm,and 47.5mm,respectively,indicating that as the pile length increases,the composite The settlement of the foundation decreases,and the bearing capacity of the foundation increases.When the pile diameter is 0.5m,0.7m,0.9m,and 1.1m respectively,the corresponding settlements of the composite foundation are 56.3mm,53.2mm,50.3mm,and 48.1mm,respectively.It shows that with the increase of pile diameter,the settlement of composite foundation decreases,and the bearing capacity of foundation increases.When the pile spacing is 1.6m,1.8m,2.0m,and 2.2m respectively,the corresponding settlement of composite foundation is 56.3mm.57.9mm,59.0mm,and 61.8mm,indicating that with the increase of pile spacing,the settlement of composite foundation increases,and the bearing capacity of foundation decreases.Through 45 days of real-time monitoring,when the pile length is 18m,22m,26m,and 30m,respectively,the corresponding settlement of composite foundation is 22.3mm,19.2mm,17.4mm,15.1mm;when the pile diameter is 0.5m,0.7 respectively.For m,0.9m,and 1.1m,the corresponding composite foundation settlemnts are 22.3mm,18.6mm,16.4mm,and 15.6mm,respectively;when the pile spacing is 1.6m,1.8m,2.0m,and 2.2m,respectively,the corresponding composite The fomdation settlements were 22.3mm,22.9mm,24.1mm,and 25.2mm,respectively.The results are calculated by numerical simulation software:When the pile lengths are 18m,22m,26m,and 30m,respectively,the corresponding composite foundation settlements are 23.7mm,21.5mm,18.3mm,and 15.9mm,respectively,which indicates that the pile length increases.The settlement of composite foundation decreases,and the bearing capacity of foundation increases.When the pile diameter is 0.5m,0.7m,0.9m,and 1.1m respectively,the corresponding settlement of composite foundation is 15.9mm,15.5mm,14.7mm,14.4mm,respectively,indicating that as the pile diameter increases,the settlement of the composite foundation decreases,and the bearing capacity of the foundation increases.When the pile spacing is 1.6m,1.8m,2.0m,and 2.2m,respectively,the corresponding composite foundation settlement is 12.7mm,13.9mm,14.4mm,and 15.9mm,indicating that as the distance between piles increases,the settlement of the composite foundation increases,and the bearing capacity of the foundation decreases.