Abstract：The data of load tests on deep jetting mixing(DJM)piles of 10 building sites in Handan city show that the skin friction of DJM pile has strengthening effect. The mechanism of strengthening effect of skin friction of DJM pile is studied by using the Meyerhof theory and the constitutive model of soil. Based on the data of load tests at 3 building sites in Handan city，the relationships of strengthening effect of skin friction with pile strength，bearing capacity of the pile-tip soil，and load level are analyzed. It shows that it is important to improve bearing capacity of foundation and reduce building settlement by choosing soil layer with better bearing capacity as the sustaining soil layer. The conclusion is also useful for designing other types of composite foundations.
