# Study on Damage Constitutive Model of Rock under Freeze-Thaw-Confining Pressure-Acid Erosion
###### Abstract  
Aiming at the acid-etched freeze-thaw rock for geotechnical engineering in cold regions, chemical damage variables, freeze-thaw damage variables, and force damage variables were introduced to define the degree of degradation of rock materials, the law of damage evolution, the total damage variable of acid-corroded rock under the coupling action of freeze-thaw and confining pressure was deduced. The continuous damage mechanics theory was adopted to derive the damage evolution equation and constitutive model of acid-eroded rock under the coupling action of freeze-thaw and confining pressure. The theoretical derivation method was used to obtain the required model parameter expressions. Finally, the model's rationality and accuracy were verified by the triaxial compression test data of frozen-thawed rocks. Comparing the test curve's peak point with the peak point of the model theoretical curve, the results show that the two are in suitable agreement. The damage constitutive model can better reflect the stress-strain peak characteristics of rock during triaxial compression, verifying the rationality and reliability of the model and the method for determining the model parameters. The model extends the damage model of rock under the coupling action of freeze-thaw and confining pressure in the chemical environment and further reveals the damage mechanism and failure law of acid-corroded rock under the coupling action of freeze-thaw and confining pressure. rock mechanics; acid corrosion; freeze-thaw and confining pressure; coupling effect; damage evolution; constitutive model +
Footnote †: journal: Applied Sciences  
0021  
Study on Damage Constitutive Model of Rock under Freeze-Thaw-Confining Pressure-Acid Erosion  
[PERSON], Y., Xiao, P., Xu, S., S., S., S., S., S., S., S., S., S., S., S., S. [PERSON], S.  
infrastructure construction such as the Sichuan-Tibet Railway and border railways, the \"14 th Five-Year Plan's\" key projects, ensuring the safety of projects in cold regions has become the primary issue. The degradation law and damage mechanism of acid-etched rock under the coupling action of freeze-thaw and confining pressure have important practical significance for constructing these critical projects. In recent years, research on the influence of acidic environment and freeze-thaw cycles on the physical and mechanical properties of rocks has attracted many scholars' attention, which has made great progress and fruitful results. Several scholars have carried out related studies on the effects of chemical solutions on different aspects of rocks, such as rock mineral composition, rock strength, Young's modulus, porosity, etc., and determined the effects of chemical solutions on the physical and mechanical properties of rock materials [2; 3; 4; 5; 6; 7; 8; 9]. Some scholars have also studied the effects of freeze-thaw cycles on various aspects of rock, such as the effects of freeze-thaw cycle temperature, freeze-thaw cycles, initial water content, etc., on different aspects of rock damage [10; 11; 12; 13; 14; 15; 16; 17; 18; 19]. However, the effect of rock on its mechanical properties under the action of freeze-thaw cycles and chemical solutions alone and the actual interaction results between the two are very different. In recent years, some scholars have also conducted research on rocks' physical and mechanical properties under the coupling effect of chemical solutions and freeze-thaw [20; 21; 22; 23; 24; 25; 26; 27]. Using the theory of continuous damage mechanics and introducing freeze-thaw damage variables, the damage evolution equation and constitutive model of rock under freeze-thaw action are derived and established [28; 29; 30; 31; 32; 33]. A uniaxial compression test was carried out for the rock immersed in the chemical solution, the chemical damage mechanism was analyzed, and the damage constitutive model was established [4; 34]. The damage evolution model of rock under the coupled chemical-freeze-thaw action is constructed [35; 36].