Research On Engineering Characteristics And Analysis Of Rammer Carrier CFG Pile Composite Foundation

Rammer carrier Cement Fly-ash Gravel (CFG) pile composite foundation is a new type of pile composite fouandation, which has the prominent advantages of both rammer pile and CFG pile composite foundation. This technique was put forward and popularized in the Southwest by Southwest Construction Survey Insitute of China. The engineering practice proved that the technique is successful, but the theory research is limited. It is necessary to do some research on bearing capability and deformation characteristics of the composite foundation to develop the theories related to the technique and to promote the practical application.The thesis is based on rammer carrier CFG pile composite foundation of the dormitory buildings of Chuanbei Medical College subsidiary hospital in Nanchong city Sichuan province. The change laws of pile axial force, soil stress between piles and pile-soil stress ratio following with load are observed and analyzed through static load test on site, buried steel strain gauge on the piles and buried soil presure cell on and under cushion layer. The characteristics of co-operation of pile and soil, reinforce mechanism, failure mode and engineering characteristics of rammer carrier CFG pile composite foundation are also researched.A more reasonable and practical computing method of bearing capability for rammer carrier CFG pile composite foundation is proposed according to analysis and contrast between field experimental data and various computing methods, design parameters are also discussed, computing theories of carrying capability for rammer carrier CFG pile composite foundation are developed. The computing theories of deformation are also discussed.Numerical simulation is made to make further research, since field experimental means, conditions and data are limited. Finite-difference softeware FLAC is applied to discuss the factors which affect the bearing capability and deformation of rammer carrier CFG pile composite foundation, that is, different load, single pile carrying capability, cushion layer depth, pile and soil modulus, pile length and space between piles. The sensitivity of the new compositefoundation to those parameters is investigated to provide evidence and reference for design and construction.