An analytical method of pile-soil stress ratio for pile-net composite foundation in consideration with the influence of pile-soil differential settlement

The pile-soil stress ratio is an important control parameter for pile-net composite foundation design, which is affected by soil arching effect, membrane effect and pile soil interaction as well as their coupling action, therefore, a concentric arch model is firstly introduced to establish a new analysis model for soil arch effect of pile-net composite foundation considering the relationship between pile-soil differential settlement and the mobilized degree of soil arch effect, and the deformed surface of horizontal reinforcements is regarded as the combination of sphere and cylinder according to its deformation characteristics, a membrane effect analysis model which reflects the influence of pile-soil differential settlement is developed. Secondly, considering the pile-soil interaction and their differential settlement, a load-transfer analysis model of pile-net composite foundation is developed with consideration of the coupling effect among fillings, net and pile-soil reinforcement area, and then a new analysis method of pile-soil stress ratio is put forward. This method can reflect not only the influence of soil arching effect, membrane effect and pile soil interaction on pile-soil stress ratio but also the influence of pile-soil differential settlement on mobilized degree of soil arching effect and membrane effect as well as pile soil interaction. Finally, the feasibility and rationality of the analysis method in this paper are verified through calculation of practical engineering examples and comparison with other existing similar methods.