Abstract:

Jet grouting soil-cement-Pile strengthened Pile (JPP) is a new kind of composite pile composed of high pressure jet grouting pile and prestressed concrete core pile. In order to make a further research on load transfer mechanism of JPP under vertical loads, the full-scale model test of JPP, cast-in-place pile and jet grouting soil-cement pile have been done in the test room which is developed for this test. With the pre-arranged instrument in JPP, the axial stress, dip resistance and settlement of pile have been measured; and distribution of axial force and friction resistance are also analyzed. Experimental results show that: bearing capacity of JPP is thirty percent higher than that of cast-in-place pile which has the same length and diameter with JPP. The deformation of JPP is controlled by core pile; axial force distribution of PHC is different with soil-cement; and their axial force ratio in same section is their elastic modulus ratio. Distribution of inner and outer friction resistance is similar; and the inner friction is about 1.62 times of the outer one; it is about the ratio of JPP diameter and PHC diameter. Furthermore, the relation between friction resistance and relative displacement is similarly hyperbolic; and the relation between dip resistance and displacement is also hyperbolic.

Key words: JPP, full-scale model test, load transfer mechanism, friction resistance