Formula of pile-soil stress ratio in pile-net composite ground

Pile-net composite ground is a new method for ground improvement which comprises both vertical piles and horizontal net-geosynthetic. In this kind of composite ground, net and piles as well as soil work together and perform compatibly, thus many advantages such as small settlement deformation, good stability and short construction period have been found in practical engineering and theoretical research. And it has been concluded that the pile-soil stress ratio is an important parameter for design and research of pile-net composite ground, therefore based on the field research and measurement data, combined with previous research, a calculation formula of pile-soil stress ratio in the pile-net composite ground which were composed of sand piles and sand cushions reinforced with one-layer of geogrid was proposed taking the effect of the reinforcement. The comparison between calculated and observed field results showed the formula is applicable and much better than the formula without taking into account the influences of the reinforcing net. Through the analysis sensitivity, the main parameters which have influence on the pile-soil stress ratio were found out and the relations between these parameters and the pile-soil stress ratio were given. This formula can be the reference in design and the basis of further research in the future.