An Investigation of Non-Linear Strength Characteristics of Solidified Saline Soils in Cold Regions

Abstract

To date, the modelling of constitutive equations of solidified frozen saline soil have seldom been studied. This paper presented the formulation of a damage constitutive model for solidified saline frozen soil considering both freeze thaw cycles (FTCs) and salinities. To model the solidified frozen saline soil, the unconfined compression strength test (UCST) and consolidated undrained (CU) triaxial shear test were conducted under three ambient temperatures (20, –10, and –20 °C), five ages (3, 7, 14, 28, and 90 d), six salinities (0, 1, 2, 3, 4, and 5%), and four FTCs (0, 5, 10, and 14 times) in this research. The UCST results showed that the unconfined compressive strength (UCS) of the solidified saline soils at an age of 14 days can reach 75% of the maximum UCS, which basically meets the engineering construction requirements. The range of the rate of strength loss as affected by salinity was 16.2% to 75.65%, while the coupling effect of salt and frozen conditions amplified the rate of strength loss. Affected by increasing salinity, the rate of strength loss of frozen soils was magnified by a factor of 1.2 to 3.7 compared to thawing soils. Likewise, the CU triaxial shear test showed that the rate of strength loss of shear strength was amplified by the coupling effect of FTCs and salt erosion. With increased FTCs, the strain threshold of Young’s modulus was gradually pushed backward, which was similar to the effect of salinity. Remarkably, the damage constitutive model performed better than conventional constitutive models for the solidified saline soil under the salt–freezing coupling effect.

Influence of soil salinity on the bearing capacity of the frozen wall

“…In general, the determination of mechanical and strength properties of frozen soils containing dissolved salt has been addressed in numerous studies within the field of permafrost science [6][7][8][9][10][11][12][13][14][15][16][17]. Previous studies have explored the influence of temperature and unfrozen water content on soil strength properties [6], investigated the time dynamics of frozen soil strength properties [7], and examined changes in mechanical and strength properties under high-cycle temperature loading conditions [8,9]. A number of studies on the impact of dissolved salt on the strength criterion of frozen soil are presented in the literature [13].…”

Fiber Solidification Treatment of River and Lake Wastewater and Sediments: Deformation Characteristics and Microscopic Mechanism Research

“…Common solidifying agents for solidified soil include cement, quicklime, and fly ash. Numerous scholars have conducted experiments employing various methods, with a primary emphasis on saline soil [3][4][5][6][7][8], loess [9][10][11][12][13][14], and other typical soil types [15][16][17]. The existing studies show a comparatively limited focus on the solidification of dredged sediment from rivers and lakes.…”