Experimental Study On The Model Of Post Grouting Anti-drawing Support Plate Pile

Squeezing and expanding the pile is a kind of variable section pile that has emerged in recent years.Compared with ordinary equal section straight piles,its branch plate will be compacted in advance due to the soil around the branch plate when it is formed.The compression strength of the soil and the friction resistance between the support plate and the soil body are enhanced.Therefore,the whole pile body shows higher tensile strength and smaller upper pull displacement,which has good social and economic benefits.When traditional extruded support plate pile is subjected to vertical upward pull load,the soil in the upper part of the support plate will often undergo large plastic deformation and produce plastic damage,so the end bearing effect of the support plate can not be fully exerted.Based on this,this paper improves the traditional extruded and extended plate pile,applies the innovation of post-grouting construction to the reinforcement of soil above the plate,and adopts the analysis method of indoor model test and numerical simulation.This paper systematically and deeply studies the vertical tensile resistance of the extruded extended plate pile.The details are as follows:(1)According to the relevant documents at home and abroad,the pile formation mechanism,bearing capacity calculation theory and other contents of the traditional extruding support plate piles are analyzed,and the post-grouting construction process,grouting tube layout,grouting pressure are also analyzed.The size of grouting quantity and grouting theory were studied,and the reinforcement mechanism of extruded and expanded pile was analyzed.(2)Through indoor model tests,the normal cross-sectional straight piles,the traditional extruded support plate piles,and the improved extruded support plate piles are respectively added with pull loads,and the load-upper drawing curve charts are drawn.Comparison and analysis of the three upper pull characteristics and bearing capacity of the size.The analysis shows that the bearing capacity of the post grouting support pile has been improved obviously,the bearing capacity of the single pile is about 140% of the pile,and the pulling capacity is small under the same load,which shows a good economic benefit.(3)Using ABAQUS finite element software,a model of traditional extruded andmodified extruded plate piles is established,and the axial force values under each load are extracted by applying a graded pull load on the top of the pile.The load transfer laws of the pile after improvement are studied,and the displacement and stress of the soil around the pile are analyzed and compared.The analysis shows that the load transfer curve of the post grouting support plate pile is in the position of the support plate,and with the increase of the load,the support plate shows better end support performance.