地面超载作用下软土隧道双对数非线性固结研究OACHSSCD

This paper establishes a two-dimensional nonlinear consolidation model for soft soil around tunnel,based on a double-logarithmic nonlinear compression and permeability constitutive relation.The governing equations are solved using the finite element method,and the influence mechanisms of the compression index,permeability index,initial self-weight stress,and external load on consolida-tion characteristics are systematically analyzed.The results show that a larger compression index leads to a greater reduction in void ratio under the same increment of effective stress,which in turn causes a more significant decrease in permeability coefficient,thereby slowing the consolidation process.Hence,accurate measurement of the compression index is essential in engineering practice.A larger permeability index results in a weaker reduction of the permeability coefficient for the same change in void ratio,which relatively enhances soil permeability and accelerates consolidation.An increase in initial self-weight stress helps promote consolidation,and its beneficial effect should be considered in deep-buried soft soil tunnel engineering.The external load primarily affects the initial pore water pres-sure distribution,with a relatively minor impact on the consolidation rate.The sensitivity of each factor to the consolidation rate,in descending order is compression index,initial self-weight stress,permeability index,external load.