Abstract:The paper studies some problems existing in CFG pile composite ground treating deep soft foundation in express way construction. Two new methods to design and calculate composite ground pile distance are put forward according to post-construction settlement and effect of driving pile in CFG pile composite ground by use of the theory of cavity expansion base on criterion and experience. The effect of driving pile in CFG pile composite ground is calculated and analyzed. The paper has carried on mathematics to derive to the soil around the pile modular according to effort balance analysis and taking into account compaction effect. The radius of compaction zone is derived based on the theory of cavity expansion.