Experimental Study and a 3D Compression Model on the Compressibility of Saline Clayey Sand

Abstract

The compressibility of saline soil is crucial to infrastructure construction in saline areas. In the present study, oedometer tests were conducted on samples of artificial saline clayey sand with varying salt content to study the compressibility of saline soil in northwest China. The initial void ratio formula for saline clayey sand was proposed to account for changes in salt concentration and the condition of the salt phase by theoretical analysis of the three-phase sketch. To validate the proposed formula, nuclear magnetic resonance was employed to evaluate the pore size distribution for three distinct salt concentrations, both quantitatively and qualitatively. An elastoplastic compression model was utilized to analyze the evolution rules of the compression parameters based on the oedometer test results. It was discovered that the compression parameters increase linearly with the increase of salt content when the salt content is below the saturated salt content but remain constant once the saturated salt content is exceeded; in contrast, swelling parameters are independent of salt content. A three-dimensional (3D) compression model was developed based on the elastoplastic model by introducing the concept of osmotic suction (π) for salt content below the saturated salt content. The experimental results obtained from samples with 0.0%, 2.0%, and 4.0% salt contents were used to determine the parameters of the fitted equations, while those with 0.5%, 1.0%, and 1.5% salt contents were utilized to validate the model. The fitted curves of the 3D compression model exhibited good concordance with the experimental results, demonstrating the correctness and effectiveness of the proposed model.