Work

Coupled Effects of Confining Pressure and Freeze–Thaw Cycles on Shear Strength and Deformation Characteristics of Moraine Soil

Year: 2026

Type: article

Abstract: The mechanical properties of moraine soil in cold regions are significantly influenced by freeze–thaw cycles (FTCs). However, current understanding of the quantitative characteristics of its shear behavior under the coupled effect of FTCs and confining pressure is still insufficient. To address this, a series of triaxial unconsolidated-undrained shear tests were conducted on saturated moraine soil, with different numbers of FTCs (N = 0, 1, 4, 8, 10, 12, 15, 20) and various confining pressures (σ3 = 100, 200, 300, 400 kPa). The experimental results reveal that: (1) With an increase in the number of FTCs, the stress–strain curves gradually change from strain-softening to strain-hardening types. Correspondingly, the pore water pressure development shifts gradually from a peak-decay pattern to a growth-stabilization pattern. The peak pore water pressure rises linearly with increasing confining pressure, whereas it decays linearly with an increasing number of FTCs. (2) Both the secant modulus E50 and the shear strength increase with higher confining pressure and decrease with more FTCs. Confining pressure exerts a significant inhibitory and compensatory effect on freeze–thaw-induced damage, markedly reducing the deterioration rate under high confining pressure. (3) Quantitative prediction models for E50 and qmax were established, effectively capturing the coupled effect of confining pressure and FTCs. It can be inferred that confining pressure mitigates structural damage by compressing frost-induced cracks and enhancing interparticle contacts, while FTCs exacerbate the degradation of soil mechanical properties because of ice crystal expansion or contraction and weakening of cementation. This study quantifies the coupled effect of confining pressure and FTCs, and the proposed prediction model provides a useful reference or preliminary estimation for relevant geotechnical engineering designs.

Source: Geotechnics

DOI: 10.3390/geotechnics6030087

Authors: Yuanyong Zeng, Xiewen Hu

Institution: Southwest Jiaotong University

Language: English

Topic: Geotechnical Engineering and Soil Mechanics

Subfield: Civil and Structural Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $1,207

Funder: National Natural Science Foundation of China