Abstract:Jet grouting(JG) soil-cement-pile strengthened pile(JPP) is a new kind of composite pile composed of high-pressure jet grouting pile and prestressed core pile. In order to make a further research on load transfer mechanism of single JPP with cap,the large-scale model test has been done on the self-developed foundation model slot. With the prearranged instrument in JPP and soil under cap,the following main characteristics of load transfer are drawn. (1) Compared with single JPP,JPP with cap has larger bearing capacity,and the ratio of load carried by cap is higher. (2) The relative displacement between JPP and soil is controlled by cap,which leads to the fact that the friction resistance does not exert sufficiently. (3) Pile-soil stress ratio of JPP with cap is between 20 and 100,and the ratio on the pile top is around 22,about twice the ratio of cap area and pile area. (4) The cap of JPP makes friction resistance decrease and tip resistance increase;and the displacement of the ultimate resistance is larger than that of JPP without cap. These results are beneficial for cap-JPP-soil interaction research.