Calculation Of Bearing Capacity Of Geosynthetic-encased Gravel Pile Based On Column Caivty Expansion Theorem

Owing to its good engineering performances, stone columns composite foundation has been widely used in the reinforcement processing of road embankment, bridges, ports and civil buildings. When stone column be used in soft soil,the perofrmances of it’s bearing capacity usually limited by lateral confinemet from the soil. And setting geosynthetics at the top of stone column or using reinforced concrete sleeves are being applied in projects, through which technology bearing capacity of stone column is greatly improved. In this paper,the cavity expansion theoren was considering,and on the basis of which it also completes other main work as follows:⑴In order to analyse the geosynthetic-encased stone column,based on the column cavity expansion theorem and considering the influence of the soil gravidity stress,the ultimate bearing capacity calculation formula of single pile was deduced when Mohr-Coulomb yield criterion was adpoted.⑵The bearing capacity calculation method of geosynthetic-encased gravel piles was established in the premise of considering expansion overlap.And the bearing capacity calculation formula of pile groups also given in this paper.It was further pointed out that this method was very different from the traditional cavity expansion theory.⑶On the basis of the unified strength theory, the bearing capacity formula for both single pile and pile groups was proposed.Under the further study of effects by different strength criteria,the infulence to the ultimate bearing capacity was also analyzed in this paper.⑷In order to validate the proposed method,a case history was illustrated. the result demonstrates that the calculation models of single pile and pile groups was practicability. And the further analyses indicates that in the calculation of bearing capacity of geosynthetic-encased stone columns considering the effects between pile groups were very necessary.