A Modified e–p Curve Model for Red Clay Considering Nonlinear Rebound

The soil pore ratio-pressure curve is an important factor in the calculation of foundation settlement by layer wise summation method. In order to establish the pore ratio-pressure curve analysis model of red clay in the whole process of lateral confined compression accurately, it is necessary to make a nonlinear correction to the analytical model of unloading rebound of red clay. Firstly, in the initial compression process of red clay, the stress-strain relationship of soil was assumed to obey the hyperbolic equation, and the analysis model of initial compression pore ratio and pressure curve of red clay was established. Secondly, according to the results of laboratory consolidation tests, the pore-pressure curve of red clay unloading rebound changes linearly when the unloading ratio is less than 0.5, and parabola changes when the unloading ratio is between 0.5 and 1.0. The piecewise function is used to characterize the unloading rebound process of red clay, and the second half of the unloading rebound curve of red clay is nonlinearly modified. Finally, the tangent modulus of the initial compressive stress-strain curve of red clay at the preconsolidation pressure was approximately equal to the secant modulus of the unloading rebound curve to calculate the initial pore ratio of recompressed soil, and then the analysis model of pore ratio and pressure curve of recompression of red clay was established. Through the comparison and analysis of theoretical calculation and measured results, the rationality of the pore ratio and pressure curve analysis model established in this paper is verified.