CFG Pile Composite Foundation On Key Technical Problems

In recent years, urban development, the proposed height of growing natural soil strength and deformation can not meet the requirements of CFG pile (cement.flyash.gravel pile, cement fly ash gravel pile acronym) is widely used in multi.storey buildings, the high.rise building foundation treatment through a large number of pilot studies and theoretical analysis has been made more abundant practical experience. Engineering, how CFG pile selected geotechnical parameters, how to accurately determine CFG pile composite foundation bearing capacity, how to prepare for the construction plan is directly related to safety, investment and progress.This paper summarizes recent years CFG pile composite foundation theory, engineering experience and its current condition.CFG pile on more projects composite foundation load test data, P～S curve characteristics of research, experiment on the use of load bearing capacity of composite foundation that the eigenvalue method has been systematically studied, summarized; Proposed pile soil stress ratio, the piles of soil compression modulus ratio simple formula.CFG pile construction, soil around the pile, the pile.a great deal of soil standard penetration test or heavy dynamic penetration test; Construction of proof, to a stratified layer and identification; After construction, the soil around the pile to standard penetration test. After provide pre.construction and construction after the pile soil bearing capacity, a statistical analysis of CFG pile foundation bearing capacity eigenvalue parameter estimation formula coefficient alpha f_sk increasing the value recommendations (αfoundation for the reinforcement of CFG pile after pile of soil bearing capacity eigenvalue natural foundation bearing capacity and the ratio of eigenvalues); Then according to Load test information to draw the composite pile foundation bearing capacity CFG eigenvalues, Calculation Pile Capacity,A statistical calculation CFG pile Limit lateral friction standard value Increasing coefficientλ₁, Limit . resistance standard value Increasing coefficientλ₂(λ₁,λ₂ were CFG pile limit lateral resistance standard value, the limit value.resistance standards bored piles and artificial limit lateral resistance standard value, the limit value of the standard tip resistance ratio). Treatment of CFG pile foundation part of the process of compiling the program difficult to solve the problem, not part of the construction process in the operation, easy to stay hidden safety problems, links, made a systematic analysis, and the corresponding solutions;Through this research, test methods to determine load bearing capacity of composite foundation CFG pile with the characteristic values coincide more closely with the actual estimate of CFG pile foundation bearing capacity eigenvalue parameter values in the formula more accurately, dealing with the establishment of more stringent program improved construction quality can be guaranteed.