Analysis of factors influencing bearing characteristics of jet grouting soil-cement-pile strengthened pile

Jet grouting soil-cement-pile strengthened pile (JPP pile) is a new kind of composite pile composed of high pressure jet grouting pile and prestressed core pile. JPP pile has different combination forms depending on soil conditions as well as the bearing capacity requirements. Based on the simplified calculation method presented, the main factors of JPP pile bearing mechanism, different combinations, different soil-cement thicknesses, different elastic moduli of soil-cement, and different stiffness coefficient ratios, are analyzed comparably. The axial force of core pile, soil-cement axial force, first interface resistance and second interface resistance, are discussed respectively. The research results show that: (1) The sub-combination JPP pile has better carrying effect and should be adopted in actual construction. (2) Increasing soil-cement thickness can effectively improve the bearing capacity of JPP pile, but should not be too thick, and should not be greater than the radius of the core pile. (3) Soil-cement elastic modulus has small effect on axial bearing properties of JPP, but should meet structural requirements. (4) The stiffness coefficients should not be too small and not less than 100, so as to achieve deformation coordination for soil-cement and core pile, and improve bearing capacity and reduce settlement of JPP pile.