Study on radial soil pressure at interface of jacked pile between silty soil and silty clay

In order to study the variation law of total radial earth pressure at pile-soil interface during the jacking penetration of jacked pile, a full-scale in-situ test was conducted in Dongying, Shandong Province. The variation of the total radial earth pressure on the pile side with the penetration depth during the jacking penetration was obtained. Combined with the limit equilibrium theory of soil and considering the dissipation of pore water in silty soil and the degradation of soil pressure at the pile-soil interface caused by cyclic shear at the pile-soil interface during penetration, a theoretical correction formula for the limit equilibrium of total radial soil pressure on the pile-soil interface along the depth direction was established. The distribution characteristics of total radial earth pressure at pile-soil interface during penetration were discussed. The results show that the total radial earth pressure on the pile-soil interface is closely related to the soil properties. At the same penetration depth, the radial earth pressure on the pile-soil interface is degraded with the pile-soil interface (H/D), the degree of degradation in the silt is greater than the extent of degradation in silty clay, and the maximum extent of degradation is 14.22%. When using the limit equilibrium theory to calculate the total radial earth pressure on the pile-soil interface in saturated silt, the dissipation characteristics of pore water should be considered, and the excess pore pressure dissipation coefficient is 0.7-0.8. The total radial soil pressure degradation amplitude of pile-soil interface in different soil layers is related to H/D, which can be expressed as a power function. The shear degradation coefficient in silt and silty clay are 0.19 and 0.12, respectively. When the limit equilibrium theory is used to calculate the total radial earth pressure at the pile-soil interface at different pile body position (H/D) during jacking, the pile length effect, which is shear degradation effect, needs to be considered. The theoretical calculation results of the proposed limit equilibrium theory formula considering pore water dissipation and shear degradation correction, are in good agreement with the measured values. © 2021, Central South University Press. All right reserved.