Research On Mechanism And Calculating Method Of Settlement Of Composite Foundation With CFG Piles

It's known that composite ground has been widely used in constructions, because it can enhance bearing capacity of natural ground with relative small cost. However, further research is necessary, as theoretical study is far behind practice, moreover, precise theory and design method are still not available. The following questions are discussed in this paper:1. The vertical loading on CFG pile composite foundation is borne by co-action of pile cushion, piles and the earth. There are so many influential factors to composite foundation bearing mechanism that further study is necessary. With ANSYS FEM program, the characteristics of single pile are studied with pile axis stress, pile-soil stress ratio and settlement changed by factors such as load, thickness of the pile cushion, length of pile, etc, moreover, the effect to axis stress of the CFG by negative friction resistance due to the soil among piles, and negative friction resistance due to above factors are analyzed. With the analysis above-mentioned, we can direct further engineering practice better.2. This paper optimizes one calculating method considering the mutual action of pile cushion, pile and the earth. By compared with engineering sample, it shows that the calculating results are well consistent with the practice. Then, advantages and disadvantages of both methods are compared, it's founded that although the improved method isn't as accurate as the composite-modulus method, it can working-out pile-soil stress ratio and position parameters of the settlement contour flat, so can be considered as a new way to settlement calculating of CFG composite foundation.3. Finally, the paper educes some conclusions and puts forward some prospect about the work should be do of CFG pile composite foundation.