Abstract
To study the mechanical properties of frozen soil, it is necessary to understand the damage characteristics of frozen soil. Four types of three‐dimensional indoor tests of frozen sand were carried out at −5°C, −10°C, and −15°C to study the mechanical damage properties. These include different stress path tests with the principal stress coefficients of 0, 0.25, 0.5, and 0.75 while analyzing the entire failure process. First, the three‐dimensional compression test of frozen sand was studied to analyze the influence of temperature and intermediate principal stress coefficient on the large principal stress of frozen soil. The damage cost of frozen sand under the influence of different temperatures and intermediate principal stress coefficients was also established. Second, using the characteristics of discreteness and randomness of the distribution of the microelements inside the frozen soil and assuming that the failure of the microelement of the frozen soil obeys the Weibull distribution, the Drucker–Prager strength criterion was used as the statistical distribution variable of the microelement of the frozen soil based on the strain equivalence hypothesis, statistical theory, and continuous damage mechanics. This allows for a constitutive model of frozen sand damage under the three‐dimensional stress state to be established. Finally, the model parameter values through low‐temperature three‐dimensional test data were able to be determined. This model allows for the physical meaning of Weibull distribution parameters F0 and m to be analyzed, and the distribution parameters with temperature and intermediate principal stress coefficient can be modified to obtain a modified frozen sand damage constitutive model. The results show that the modified damage constitutive model can simulate the entire process curve of the large principal stress‐strain of frozen sand. It shows that the large principal stress of frozen sand increases with the increase of temperature and intermediate principal stress coefficient. Concurrently, the frozen sand damage constitutive model proposed in this paper can describe the deformation behavior of frozen soil under different temperature and stress paths and can be adapted to various other sediment types.
Highlights
Frozen soil is a relatively complex four-phase system composed of solid mineral particles, ice, liquid water, and gas [1]
Due to the existence of ice, frozen soil melts at high temperatures and freezes at low temperatures, which causes frost heave and thawing of the soil. e frost heave and thawing settlement of the soil will cause the accelerated development of randomly distributed pores, interfaces, and other defects in the interior, resulting in the formation of cracks, local shear bands, and overall damage to the soil structure. is, in turn, can cause irreversible plastic deformation
Based on previous studies [36], this paper assumes that the microelement strength distribution of frozen sand obeys the Weibull distribution [33,34,35]. is model uses the Drucker–Prager strength criterion as the microelement strength distribution variable, damage mechanics theory, and probability statistics and introduces the Weibull random distribution parameter m and the relationship between F0 and temperature and the medium principal stress coefficient
Summary
Frozen soil is a relatively complex four-phase system composed of solid mineral particles, ice, liquid water, and gas [1]. Due to the existence of ice, frozen soil melts at high temperatures and freezes at low temperatures, which causes frost heave and thawing of the soil. E frost heave and thawing settlement of the soil will cause the accelerated development of randomly distributed pores, interfaces, and other defects in the interior, resulting in the formation of cracks, local shear bands, and overall damage to the soil structure. Settlement due to frost heaving and thawing of the soil accelerates the damage of the soil structure. The damage mechanics of frozen sand is an important research subject within frozen soil mechanics
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