关键词: 径向固结, 变固结系数, 三维强度, 剪切模量

Abstract: Taking the stress state of soil around jacked pile as the initial condition, a Terzaghi's consolidation equation is modified under the axisymmetric conditions considering that the consolidation coefficient varies with time regarding the correlation between void ratio, permeability coefficient and effective stress. Subsequently, a semi-analytical and semi-numerical solution of excess pore water pressure dissipation is derived by using separation of variables and discrete analysis and compared and verified with the measured data. On this basis, the soil 3D undrained shear strength is defined by using SMP criterion-based Cam-clay model. The strength of soil around jacked piles and the variation of shear modulus with consolidation time are researched. The results show that the theoretic solution is well consistent with the measured data because of considering the change of the consolidation coefficient. And the ratio of the compressibility index and the permeability index has significant effects on the variations of consolidation coefficient and the consolidation rate. When the ratio equals to 1, the consolidation coefficient will be constant, the solution is degenerated into the conventional Terzaghi’s axisymmetric consolidation equation. Also the soil strength and the shear modulus gradually increase along with the consolidation time. In the long-term stage of consolidation, their values exceed in-situ strength and in-situ shear modulus.

Key words: radial consolidation, variable consolidation coefficient, three-dimensional strength, shear modulus