Gravel Pile-CFG Pile Double Pile Composite Foundation Theory And Engineering Characteristics Research

As our country's development and urbanization pick up speed,the heights and loads of buildings grow accordingly,thus ground formation becomes a sensitive element to building foundation.In order to meet the building load and settlement requirements and achieve cost-saving purposes,the composite foundation technology has been well studied and applied,forming a relatively complete system of theory and practice and accomplishing good results in foundation treatment project.Because of the complex geological conditions in our country,soft foundation is not rare in urban constructions,upon which composite foundation is commonly applied to solve corresponding problems.In foundation treatment project,engineering geological conditions are not the same in different venues,different buildings have different requirements in terms of foundation.So,it is difficult to meet the requirement of load and deformation of buildings when we use a single composite foundation treatment method.In order to make full use of the advantages of a single composite foundation approach,we make two and more pile types composite foundation treatment methods to form multiple pile type composite foundation.Given that the gravel pile-CFG pile double pile composite foundation has been applied in the project,its mechanism of action and engineering properties are less researched.Therefore,this paper initiates a study on action mechanism and engineering properties of gravel pile-CFG pile double pile composite foundation.The layout of the paper is as follows:(1)Compare composite foundation with natural foundation and pile foundation,elaborate the advantage of composite foundation in terms of engineering characteristics and cost,and analyzes reinforcement mechanism and engineering characteristics of the single gravel pile composite foundation and the single CFG pile composite foundation;(2)Analyze several commonly used settlement calculation methods and calculation methods of double pile type composite foundation.While consider the load,cushion thickness and construction order changes,we study the double pile composite foundation reinforcement mechanism and engineering characteristics by indoor model test and analyze the load-settlement law,transfer law of pile soil stress,the stress variation of the pile,the pile soil load sharing ratio and it influences the treatment effect of the foundation when the construction order be changed;(3)Use gravel pile-CFG double pile type composite foundation to specific project,analyze the field test data and Draw load-settlement curve,pile-soil stress ratio curve,compare load-settlement curve with pile soil stress ratio curve of indoor laboratory simulation experiment,verify indoor simulation experiment analysis and its correctness.