Study on the Unified Mechanical Properties of Ili Undisturbed Loess under the Influence of Soluble Salt

Abstract

Through three stress path tests of unsaturated Ili undisturbed loess, the effect of soluble salt content on the deformation of net mean stress, suction, and deviated stress were investigated. The mechanical properties of the normalized compression curve, soil water characteristic curve and critical state line were revealed. The test results indicate that: in the isotropic compression test, the normal compression curves controlling different suctions can be characterized by using the initial void ratio and the yield net mean stress, and can be described as a two-parameter exponential function. In the triaxial shrinkage test, the soil water characteristic curves controlling vary net mean stresses are dimensionless by using saturated moisture and air entry value, and the normalization formula can be characterized by a single parameter exponential function. In the consolidation shear test, the corresponding effective net mean stress is calculated by suction and saturation. The critical state lines under the unsaturated condition controlling vary suctions can be described as the critical state line under the saturated condition on the plane of effective net mean stress and deviator stress. When the effective net mean stress is constant, the critical state lines under the unsaturated condition can be characterized by the degree of gas saturation and the ratio of unsaturated void ratio to saturated void ratio. The research will offer reference pointing at the regulation and utilization of water and salt in the loess region of Central Asia, so as to better guarantee the sustainable development of saline-alkali land project construction.

Deformation and Strength of Unsaturated Loess—Hydraulic Coupling Effects under Loads

“…Volume change is one of the most basic characteristics of soil [8]. Through isotropic compression tests with constant suction, the normal compression curve of unsaturated loess flattens and moves downward as the suction decreases [9,10], indicating that the suction level has a significant impact on the compressibility of unsaturated loess [11]. Triaxial tests are widely regarded as the most appropriate approach for researching the mechanical properties of rocks and soils in laboratory settings.…”