Prediction Method of Saturated and Unsaturated Permeability Coefficient of Deformed Soil Based on Fractal Theory

Abstract

The invention discloses a prediction method for saturated and unsaturated permeability coefficients of deformed soil based on a fractal theory. The prediction method comprises the following steps: taking a soil-water characteristic curve of soil samples before deformation as a reference state, using a fractal model of the oil-water characteristic curve and fitting to obtain a fractal dimension D0 and an air entry value Psi a0 before the deformation, making the fractal dimension unchanged before and after the deformation, combining with a prediction model of the deformed air entry value to obtain a deformed air entry value Psi a, combining the deformed fractal dimension D0 and air entry value Psi a through a saturated / unsaturated relative permeability coefficient model, predicting the saturated permeability coefficient and an unsaturated relative permeability coefficient of the deformed soil, and multiplying the saturated permeability coefficient and the unsaturated relative permeability coefficient to obtain the unsaturated permeability coefficient. The prediction method for the saturated and unsaturated permeability coefficients of the deformed soil based on the fractal theory disclosed by the invention overcomes the defects that the prediction of the permeability coefficients is empirically based, thereby lacking theoretical support and having complicated calculation, and has the advantages of having extremely important values in seepage theories and fluid-solid coupling research and engineering application of saturated / unsaturated soil.

Description

technical field [0001] The invention relates to the technical field of saturated / unsaturated soil seepage analysis and hydraulic coupling research in geotechnical engineering, and more specifically relates to a method for predicting saturated and unsaturated permeability coefficients of deformed soil based on fractal theory. Background technique [0002] The research shows that quantitatively describing the influence of soil deformation on the saturated / unsaturated permeability coefficient is the basis for establishing a soil constitutive model considering the interaction of hydraulic and mechanical properties, and conducting research on fluid-solid coupling analysis of unsaturated soil. It is of great significance to establish a prediction method for saturated / unsaturated permeability coefficient of soil under deformation conditions. [0003] For the saturated permeability coefficient under deformation conditions, it is generally predicted by establishing an empirical relat...

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Problems solved by technology

[0003] For the saturated permeability coefficient under deformation conditions, it is generally predicted by establishing an empirical relationship with the void ratio. This method does not study the relevant mechanism deeply enough, and the prediction accuracy needs to be improved.

[0004] For the unsaturated permeability coefficient under deformation conditions, the empirical method or semi-empirical and semi-theoretical prediction is currently the main method, and the calculation is quite cumbersome and lacks theoretical support.

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