Analysis Of Working Mechanism Of CFG Pile Composite Foundation

CFG pile composite foundation technology is a popular research direction in geotechnical engineering now. Though this technique developed a lot in recent years and has been diffusely applied in engineering, its theoretical study is lagged far behind engineering practices. Thus, there is no doubt that research implemented for working mechanism of CFG pile composite foundation possesses significant practical implications.At first, in this paper, materials of CFG pile composite foundation were elaborated. Those main factors may effect the strength of the CFG pile are the content of cement and fly-ash. water cement ratio, pumping agent content, curing condition, curing age and so forth. The strength and modulus of CFG pile can be hardly affected by ambient pressure, because the CFG pile possesses the characteristics of the rigid pile, and the pile body plays a replacement or compacting role in composite foundation. Next, the importance of cushion was introduced, and the scopes of materials and thickness was concluded and classified. Stress concentration of the bases was reduced through the adjustment of pile-soil load share ratio by cushion settings, for the purpose of full use of bearing capacity. Research concerning deformation mechanism of CFG pile composite foundation has been conducted from the perspective of bearing capacity and displacement, and some calculation methods of bearing capacity and settlement were enumerated, advantages, disadvantages and application range of each method were analyzed as well. At last, numerical simulation of CFG pile composite foundation was performed with reference to practical engineering by using finite element analysis software ANSYS, the results indicate that:(1) Calculated results of the three-dimensional finite element model based on practical engineering were in consistence with measured values, and the variation trend of numerical value in each stage is similar, which means the results calculated in this model is definitely reliable and can be applied to practical engineering. (2) The fact that settlement displacement of composite foundation can be affected by the adjustment of parameters such as pile length, pile spacing and pile diameter, was validated, and a set of more optimized parameters were concluded by performed simulations, i.e.a pile length of 11 m, a pile diameter of 400mm and a pile spacing of 2000mm. (3) The numerical simulation optimization method provides an idea for similar problems in future projects.